Contents
MEDICAL RADIOLOGY
Diagnostic Imaging
Editors:
A. L. Baert, Leuven
M. Knauth, Göttingen
K. Sartor, Heidelberg
I
Contents
Stefano Bianchi · Carlo Martinoli
Ultrasound
of the
Musculoskeletal
System
With Contributions by
L. E. Derchi · G. Rizzatto · M. Valle · M. P. Zamorani
Foreword by
A. L. Baert
Introduction by
I. F. Abdelwahab
With 1111 Figures in 3669 Separate Illustrations, 286 in Color
123
III
IV
Contents
Stefano Bianchi, MD
Privat-docent
Université de Genève
Consultant Radiologist
Fondation et Clinique des Grangettes
7, ch. des Grangettes
1224 Genève
Switzerland
Carlo Martinoli, MD
Associate Professor of Radiology
Cattedra “R” di Radiologia - DICMI
Università di Genova
Largo Rosanna Benzi, 8
16132 Genova
Italy
Medical Radiology · Diagnostic Imaging and Radiation Oncology
Series Editors:
A. L. Baert · L. W. Brady · H.-P. Heilmann · M. Knauth · M. Molls · C. Nieder · K. Sartor
Continuation of Handbuch der medizinischen Radiologie
Encyclopedia of Medical Radiology
Library of Congress Control Number: 2003057335
ISBN 978-3-540-42267-9 Springer Berlin Heidelberg New York
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Contents
D e dicat ion
To Maria Pia, Elena and Eugenio,
the loves of my life – S.B.
To Maura and Roberto,
for their love, support and forbearance – C.M.
V
Contents
Series Editor’s Foreword
Modern ultrasound has now acquired a very important role in the spectrum of imaging
modalities available for the study of the musculoskeletal system.
This technique has become an indispensable tool in the clinical management of
sports injuries, degenerative and traumatic lesions of the articulations and periarticular soft tissues, as well as – in certain circumstances – clinical management of the
bones.
Stefano Bianchi and Carlo Martinoli are internationally renowned leaders in their
field who, as a long-standing and remarkable team, have acquired an exceptional expertise. This is amply demonstrated by their numerous and outstanding contributions
to the literature, as well as by their worldwide lecturing and participation in teaching
seminars on musculoskeletal ultrasound.
Although some additional chapters have been authored by other well-known ultrasound specialists, most of the chapters have been prepared and written by Stefano Bianchi and Carlo Martinoli. This feature is a guarantee for uniformity and homogeneity of style, concept and presentation throughout the whole volume. An update of our
knowledge and the latest insights into this subject are provided for each anatomic area
of the musculoskeletal system.
I would like to congratulate the authors most sincerely for their superb efforts in
preparing this remarkable volume, which comprehensively covers the extensive and
varied spectrum of musculoskeletal diseases, in the management of which ultrasound
can make an important, if not essential, contribution to better clinical diagnosis and
better guidance of therapy.
Moreover, this work is superbly and abundantly illustrated by numerous anatomical
drawings, photographs and ultrasound images, all realized with state-of-the-art and
high-end equipment. These well chosen illustrations strongly enhance the didactic and
educational value of this book.
Without doubt, this outstanding volume will be of great value to certified general
and musculoskeletal radiologists, radiologists in training, as well as orthopedic surgeons and rheumatologists in their daily clinical practice. I am confident that it will
meet with the same success among readers as the previous volumes published in this
series.
Leuven
Albert L. Baert
VII
Contents
Foreword
Over the last 15 years, musculoskeletal ultrasonography has become an important imaging modality used in sports medicine, joint disorders, and rheumatology. With the
rapid development and sophistication of this modality, essential information for a better understanding of the pathophysiologic assessment of many disorders has been established. This, in turn, has aided both in making crucial decisions regarding surgical
intervention and in monitoring the effects of therapy. Equally important is the ready
availability, affordability, speed, and diagnostic accuracy of ultrasonography.
Ultrasound of the Musculoskeletal System is an invaluable text comprising 19 chapters and approximately one thousand pages and figures. The authors have designed
unique schematic drawings which aid in better understanding the anatomy of the body
part in terms of its sonographic characteristics discussed in each chapter. Correlations
of ultrasonography with CT and MRI findings are applied throughout the text, demonstrating not only the exact indications for its use, but also highlighting its limitations.
Technical advances continue to improve the utility of ultrasonography as a diagnostic technique in musculoskeletal imaging. Drs. Bianchi and Martinoli have successfully
capitalized on the collaboration between radiologists, orthopedists, and rheumatologists as exemplified by their representative images and correlative discussions. Many
of the techniques described in the text have been pioneered or improved by Dr. Bianchi
and Dr. Martinoli. This text should become a key library reference source for radiologists, orthopedists, and rheumatologists. It is extremely readable and its illustrations
help in the clarification of points made in the text. Ultrasound of the Musculoskeletal
System is the most comprehensive work of its kind to date. It establishes a higher standard in musculoskeletal imaging and should remain a classic for years to come.
Ibrahim Fikry Abdelwahab, MD
Formerly Professor of Radiology
The Mount Sinai School of Medicine,
Weill Medical College, Cornell University,
and New York Medical College
IX
Contents
Preface
The use of ultrasound in the assessment of the musculoskeletal system started many
years ago. Nevertheless, the continuing innovations in instrumentation and the
advances in clinical applications suggest that we have only just started to “peel the
onion” in this field. This fact has also been reflected in the length of time needed to
prepare this book. The project started some five years ago, with an approximate estimation of 300 pages to cover the whole field. As our personal experience and the literature expanded as a result of new technological improvements, more and more information was added, resulting in a final book size of over 1000 pages. This textbook
can be considered the result of a continuing cooperation of two friends and colleagues
who started their common practice many years ago publishing scientific papers and
teaching at courses and congresses, and then decided to put their experience into a
monograph with the aim of sharing their own knowledge and, most importantly, their
enthusiasm for this wonderful imaging technique.
Given these considerations, this book aims to cover the whole of this field, thus providing both help to those who are already expert in ultrasound and want to acquire further knowledge and skills in this special area, as well as an introduction to beginners,
irrespective of whether they are musculoskeletal radiologists, rheumatologists, orthopaedic surgeons, or in-training residents, among others. Since many of the difficulties
encountered while learning musculoskeletal ultrasound result from an inability to correctly interpret the images, many figure captions, references for probe placement, oneto-one correlations with clinical photographs, anatomical and operative specimens, as
well as images obtained with other modalities were systematically added to the ultrasound illustrations. Schematic drawings have also been extensively used throughout
the chapters to emphasize depiction of anatomy, pathomechanisms and biomechanics
underlying the disease processes. It was our deliberate intention to compile the book
with a uniform style throughout. This is the reason why most of the chapters have
been written by the two editors and by a relatively small numbers of authors who have
worked or continue to work with the editors.
The book begins with an introductory section on the instrumentation and general
aspects of musculoskeletal ultrasound, followed by a systematic overview of the applications of this technique in the different areas of the upper and lower extremities. An
additional final section devoted to both interventional and pediatric applications has
been included. With regard to certain clinical applications, there is still considerable
difference of opinion on the role of musculoskeletal ultrasound as compared to that of
other imaging modalities, such as magnetic resonance imaging. Obviously, there is a
“bias” towards the use of ultrasound in this text. However, every effort has been made
to provide accurate accounts of present knowledge and experience, as well as to indicate the most advanced references of emerging applications.
XI
XII
Preface
A new textbook of this size inevitably contains errors and weaknesses -- we welcome
corrections and suggestions for future editions.
Meanwhile, happy reading!
“Nulla res me delectabit, licet sit eximia et salutaris, quam mihi uni sciturus sum”.
(Seneca, Epist. 6,4)
“I might not be delighted with anything, even eminent and beneficial, if I am the only
one to know it”.
(Seneca, Epist. 6,4)
Genève
Genova
Stefano Bianchi
Carlo Martinoli
Acknowledgments
We are deeply indebted to the many colleagues who have provided information and illustrations of rare pathology, operative and anatomical views, as well as to the models who helped
us to obtain correlative photos of anatomical landmarks. These colleagues are listed below.
Special thanks go to Alberto Tagliafico (Genova, Italy) for the task of checking the entire
book for errors, to the „Subject Index team“, including Enrico Capaccio, Maria Beatrice
Damasio, Nunzia Pignataro, Nicola Stagnaro, Alberto Tagliafico and Simona Tosto, and to
Jane Farrell for copyediting the manuscript and correcting language errors. Finally, it is a
pleasure to acknowledge the skillful help, pleasant cooperation, and patience of the publisher’s staff during the five years of intense work it has taken to prepare this textbook.
Elena and Eugenio Bianchi (Geneva, Switzerland)
Silvio Boero (Genova, Italy)
Gianni Cicio (Genova, Italy)
Giovanni Crespi (Genova, Italy)
Marino Delmi (Geneva, Switzerland)
Jean H Fasel (Geneva, Switzerland)
Sergio Gennaro (Genova, Italy)
Maurizio Giunchedi (Lavagna, Italy)
Claudio Guido Mazzola (Genova, Italy)
Vincenzo Migaleddu (Sassari, Italy)
Roberto Pesce (Genova, Italy)
Nicolò Prato (Genova, Italy)
Fabio Pretolesi (Genova, Italy)
Maurizio Rubino (Genova, Italy)
Federico Santolini (Genova, Italy)
Giovanni Serafini (Pietra Ligure, Italy)
Stefano Simonetti (Genova, Italy)
Enrico Talenti (Padova, Italy)
Paolo Tomà (Genova, Italy)
Bruno Valle (Rapallo, Italy)
Marzia Venturini (Genova, Italy)
The Staff of the Institut de Radiologie, Clinique des Grangettes, (Geneva, Switzerland) and
the Cattedra di Radiologia “R” – DICMI, Università di Genova (Genova, Italy).
Contents
Contents
Intrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
1 Technical Requirements
Lorenzo E. Derchi and Giorgio Rizzatto . . . . . . . . . . . . . . . . . . . . . . .
3
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2 Skin and Subcutaneous Tissue
Maura Valle and Maria Pia Zamorani. . . . . . . . . . . . . . . . . . . . . . . . . 19
3 Muscle and Tendon
Maura Valle and Maria Pia Zamorani. . . . . . . . . . . . . . . . . . . . . . . . . 45
4 Nerve and Blood Vessels
Maura Valle and Maria Pia Zamorani. . . . . . . . . . . . . . . . . . . . . . . . . 97
5 Bone and Joint
Maura Valle and Maria Pia Zamorani. . . . . . . . . . . . . . . . . . . . . . . . . 137
Individual Anatomic Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Upper Limb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
6 Shoulder
Stefano Bianchi and Carlo Martinoli . . . . . . . . . . . . . . . . . . . . . . . . 189
7 Arm
Carlo Martinoli and Stefano Bianchi . . . . . . . . . . . . . . . . . . . . . . . . 333
8 Elbow
Stefano Bianchi and Carlo Martinoli . . . . . . . . . . . . . . . . . . . . . . . . 349
9 Forearm
Carlo Martinoli and Stefano Bianchi . . . . . . . . . . . . . . . . . . . . . . . . 409
10 Wrist
Stefano Bianchi and Carlo Martinoli . . . . . . . . . . . . . . . . . . . . . . . . 425
11 Hand
Carlo Martinoli and Stefano Bianchi . . . . . . . . . . . . . . . . . . . . . . . . 495
XIII
XIV
Contents
Lower Limb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549
12 Hip
Carlo Martinoli and Stefano Bianchi . . . . . . . . . . . . . . . . . . . . . . . . 551
13 Thigh
Stefano Bianchi and Carlo Martinoli) . . . . . . . . . . . . . . . . . . . . . . . . 611
14 Knee
Carlo Martinoli and Stefano Bianchi) . . . . . . . . . . . . . . . . . . . . . . . . 637
15 Leg
Stefano Bianchi and Carlo Martinoli) . . . . . . . . . . . . . . . . . . . . . . . . 745
16 Ankle
Carlo Martinoli and Stefano Bianchi) . . . . . . . . . . . . . . . . . . . . . . . . 773
17 Foot
Stefano Bianchi and Carlo Martinoli) . . . . . . . . . . . . . . . . . . . . . . . . 835
Interventional Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 889
18 US-Guided Interventional Procedures
Stefano BianchI and Maria Pia Zamorani . . . . . . . . . . . . . . . . . . . . . . 891
Pediatric Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 919
19 Pediatric Musculoskeletal Ultrasound
Carlo Martinoli and Maura Valle . . . . . . . . . . . . . . . . . . . . . . . . . . . 921
Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 961
List of Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 975
Technical Requirements
Instrumentation
1
Technical Requirements
Technical Requirements
Lorenzo E. Derchi and Giorgio Rizzatto
1.1.1
Transducers
CONTENTS
1.1
1.1.1
1.1.1.1
1.1.1.2
1.1.1.3
1.1.2
1.1.2.1
1.1.2.2
1.1.2.3
1.1.2.4
1.1.2.5
1.1.2.6
1.1.3
Advances in US Technology 3
Transducers 3
Broadband Transducers 3
Focusing 6
Transducer Selection and Handling 6
Imaging Algorithms 7
Advances in Doppler Imaging 8
Compound Imaging 8
Extended Field-of-View Imaging 9
Steering-Based Imaging 11
Three-Dimensional Imaging 13
Elastographic Imaging 14
Ultrasound Contrast Media 14
References
15
1.1
Advances in US Technology
US technology is rapidly advancing and being
refined, and is aimed at both increasing image
quality and opening new fields of applications. This
chapter will review the main advances in US technology and address the clinical impact they have
had or are likely to have in the future in the field of
the musculoskeletal system. New developments in
transducer technology and advances in the quality
and presentation of US images will be discussed.
L. E. Derchi, MD
Professor of Radiology, Cattedra di Radiologia “R” - DICMI
– Università di Genova, Largo Rosanna Benzi 8, 16132 Genova,
Italy
G. Rizzatto, MD
Head of Department of Radiology, Ospedale di Gorizia, 34170
Gorizia, Italy
The transducer is an essential element of US equipment, responsible for the generation of a US beam
and the detection of returning echoes. It greatly
influences spatial resolution, penetration and
signal-to-noise ratio. In recent years, research in
transducer technology has been focused on the
development of piezoelectric crystals with lower
acoustic impedances and greater electromechanical coupling coefficients, as well as on improving
the characteristics of absorbing backing layers and
quarter-wave impedance matching layers (Claudon
et al. 2002). Currently, transducer arrays formed by
ceramic polymer composite elements of variable
shape and thickness and multilayered technology
are used, leading to a more accurate shaping of US
pulses in terms of frequency, amplitude, phase and
length (Whittingham 1999a; Rizzatto 1999).
These refinements led to the use of very short pulses
and an increased bandwidth (Fig. 1.1).
1.1.1.1
Broadband Transducers
One of the original objectives in designing broadband
transducers was to improve axial resolution without
changing the emission frequency. This is related to
the fact that the shorter transmission pulses used in
a broadband emission generate shorter echo pulses
which can be faithfully converted into electric signals (Whittingham 1999b). Because short pulses
suffer attenuation to a greater extent and are characterized by less penetration than long pulses, some
specific techniques have been introduced by different manufacturers to compensate for these drawbacks, including single-pulse and multi-pulse techniques (Claudon et al. 2002). Among single-pulse
techniques, the emission of a long, peculiarly shaped
transmission pulse, which varies in frequency and
3
1
4
L. E. Derchi and G. Rizzatto
a
c
b
d
Fig. 1.1a–d. Relationship between spatial pulse length and frequency spectrum. a,b Intensity versus time diagrams illustrate
different pulse lengths (λ). Two sine wave pulses are shown lasting 2 µs (four-cycle) and 1 µs (two-cycle) respectively. c,d Corresponding Fourier power (intensity versus frequency) diagrams show the spectrum of frequencies present in the pulses shown
in a and b. The bandwidth is measured between the 6 dB points on each side of the spectrum. The longer pulse in a generates
a narrower bandwidth (1 MHz) than the shorter pulse (2 MHz) in b
amplitude within the duration of the pulse itself,
has been used instead of a simple sinusoidal pulse
(Fig. 1.2). When the signal is received, a filter analyzes the signal frequencies as a short pulse, erasing
the components introduced to make it long (chirp):
the result is increased image penetration with an
improved signal-to-noise ratio, without compromising axial resolution. Other multi-pulse techniques
make use of a coded-emission mode consisting of
transmission of an integrated sequence of many
short, high-frequency transmission pulses which
vary in terms of phase and are modulated in a code
sequence. When the signal is received, the signal
frequencies are compared with the transmission
pulses by a matching decoding filter working at a
high sampling rate. The subtraction process results
in increased image penetration without loss of axial
resolution or an increase in emission peak pulses
(Claudon et al. 2002).
Apart from advances in emission pulse technology, broadband transducers use a spectrum of
frequency distribution (i.e., 12–5 MHz) instead of
a single fundamental frequency (i.e., 10 MHz): the
high-frequency components tend to increase the
intensity maximum in the focal zone but cause a
prompt decrease in intensity with depth, whereas
the low-frequency components extend the penetration depth (Whittingham 1999b). In multiple-frequency imaging, the available broad bandwidth is
subdivided into multiple frequency steps for transmission and reception of sound waves: these transducers enable selection of the optimal frequency
range in a given scanning plane as though two or
more independent transducers – each with a different center frequency – were available (Fig. 1.3).
Other systems use the total transducer bandwidth
for the transmitted pulse and then adjust the receiver
bandwidth to lower frequencies as deeper depths are
Technical Requirements
a
b
Fig. 1.2a,b. US pulse shaping. a Intensity versus time diagram illustrates a short pulse wave (arrow) characterized by a few
oscillations rapidly dampened by the backing material of the transducer. This short-duration pulse is associated with a broad
bandwidth but, when transmitted through tissues, it is rapidly attenuated and absorbed resulting in a poor penetration of the
US beam. b Intensity versus time diagram illustrates a chirp pulse. This pulse has a longer duration to increase the penetration
of the US beam. It is not a simple sine wave: it is modulated in terms of phase and frequency to include a central component
(arrow) – that a receive filter reads as a short pulse to obtain high axial resolution – and two sine queues (arrowheads) on each
side of the central component to give penetration capabilities. Example of Chirped Emission (Siemens)
*
a
b
c
d
Fig. 1.3a–d. Multiple-frequency transducers. a,b Longitudinal US images obtained over the palmar aspect of the hand with a
18–6 MHz multiple frequency transducer by setting the center frequency at a 8 MHz and b 16 MHz respectively. Shifting on
the lower frequencies of the bandwidth, penetration (large open arrows) of the field-of-view is achieved; on the other hand, the
small superficial cyst (arrowheads) overlying metacarpal bone (thin white arrows) does not appear completely anechoic, subcutaneous tissue echoes are coarse and reverberation artifacts (asterisk) appear deep to the bone. Shifting the frequency band
upward, a more defined echotexture is appreciated in the superficial part of the image as a result of an increased resolution. In
contrast, a strong attenuation affects the deep part of the US image, which loses intensity. c,d Corresponding intensity versus
frequency diagrams illustrate how the frequency band is modulated in multiple-frequency transducers. Example of “eXtreme
High-Frequencies imaging” technology (Esaote)
5
6
L. E. Derchi and G. Rizzatto
sampled. These systems give increased flexibility to
the US examination, enabling the same transducer
to change the image acquisition parameters during
scanning based on the desired clinical information.
In musculoskeletal imaging, this is particularly
important when the study focuses on both superficial (i.e., subcutaneous tissue planes) and deep (i.e.,
muscle tissue layers) tissues in the same study and
body area to be explored.
1.1.1.2
Focusing
Reducing the width and thickness of the US beam
has definite advantages in terms of contrast and spatial resolution. In modern linear-array transducers,
focusing is currently not obtained by means of a
fixed lens as in the old mechanical sector probes
in which degrading of the image quality occurred
at a short distance from the focal zone (Fig. 1.4a).
Focusing is now produced electronically by activating a series of elements in the array with appropriate
delays, so that the trigger pulses to the inner elements are delayed with respect to the pulses to the
outer ones. In this way a curved wavefront results
from constructive interference bringing the US
beam toward a focus. By adjusting the values of the
delays applied to the trigger pulses, the curvature
of the wavefront and, therefore, the focal depth can
be changed dynamically. As the resulting wavefront
has the characteristics of a short excitation pulse,
the axial resolution is preserved. When the pulses
are received, the US machine continuously refocuses
them according to the position from which the echoes
come, thus giving real-time focal tracking along the
depth axis: synchronization of the received signals is
essential to minimize out-of-axis echo interference.
An important factor influencing the lateral resolving
power of the system is the dynamic aperture: this is
achieved by activating variable numbers of elements
dynamically to optimize focusing at many depths. As
a rule, the higher the number of channels (electric
pathways) involved in this process to activate the
elements in a combined mode and with appropriate
delays, the higher the complexity and the cost of the
equipment, but the more accurately the beam can be
focused. Recently, the introduction and refinement
of matrix (1.5D probes) transducers led to further
progress. In these transducers, the single row of long
piezoelectric elements found in a conventional probe
is replaced by more layers (three to seven) incorporated into a single thin layer to produce parallel
rows of short elements. The slice thickness of the US
image is improved by performing dynamic focusing
in the elevation plane (Fig. 1.4b). This leads to better
spatial and contrast resolution and reduction of partial-volume averaging artifacts (Rizzatto 1999). A
less expensive alternative to 1.5D probes is the use
of peculiar acoustic lenses –Hanafy lenses –placed in
front of the piezoelectric elements. The Hanafy lens
has non-uniform thickness and resonance properties: it produces a narrow and uniform image slice
thickness and, simultaneously, a very broad bandwidth pulse. The inner portion of the lens is thinner, resonates at higher frequencies and focuses in
the near field, whereas its outer portions resonate at
lower frequency and are focused in both transmission and reception at the deepest part of the image
providing better penetration (Claudon et al. 2002).
1.1.1.3
Transducer Selection and Handling
A variety of linear-array transducers, including large
(>40 mm), medium-sized (<40 mm) and small-FOV
(hockey-stick-shaped) probes, are currently available in the frequency range used for musculoskeletal examinations. Selection of the most appropriate
transducer primarily depends on the frequency but
is also related to other factors. Hockey-stick probes
are the best choice for imaging small superficial
structures at sites in which the skin surface does
not allow adequate contact with larger probes (i.e.,
soft tissues adjacent to bony prominences) or while
performing dynamic maneuvers: they are, however,
characterized by a restricted field-of-view which
often allows only an incomplete evaluation of the
structure of interest and surrounding anatomy.
Compared with small transducers, high-frequency
large-diameter transducers tend to have a large
near-field beam width leading to a poor lateral resolution at shallow depths. Because they maintain
beam shape to greater depths with less divergence of
the US beam, they have the best potential for imaging deep-seated structures. During evaluation of the
musculoskeletal system, probe handling has need
of maximum stability over the region of interest;
compression is never required, and the mobility of
the probe to cover wide body areas is considerably
less than in abdominal studies. Because pathologic
findings may be very small in size and are often
evaluated by placing the probe over curvilinear (i.e.,
humeral head) and irregular surfaces (i.e., cubital
tunnel), stability of the transducer is a main factor
Technical Requirements
Fig. 1.4a,b. Elevation
focusing. a Schematic
drawing shows mechanical focusing of an
electronic linear-array
transducer (in gray) with
a single row of elements
(arrows) by an acoustic
lens (in black). Note
that focusing is applied
uniformly to each crystal
of the array. As shown
on the right, a side
view of the transducer
illustrates the resulting
slice thickness of the US
beam. Using mechanical
focusing, the beam has
non uniform thickness
throughout the scanning
plane: it is narrow at a
given depth but soon
diverges away from the
focal zone. b Schematic
drawing shows a 1.5D
array transducer made
of three rows of elements
(arrows) instead of a
single row. Beam width
reduction is achieved
by electronic focusing
control in the z-plane by
introducing appropriate
delays of crystal activation. The resultant slice
thickness is uniformly
narrow throughout the
scanning plane
a
b
required for high-quality examinations. In our experience, the best grip to obtain probe stability can be
obtained by placing the ulnar fingers (long, ring,
little) directly on the patient’s skin while holding
the probe with the radial fingers (so that the probe
hangs between the thumb and the index finger). This
grip allows easy translation of the probe along its
short axis at a given angle minimizing rotational
changes. When possible, the examiner being in a
lower position than the patient (i.e., the examiner
seated on a chair and the patient supine on the bed
at the level of the examiner’s shoulder) may also help
to achieve probe stability.
1.1.2
Imaging Algorithms
Recent technologic innovations in US have resulted
in improved diagnostic performance for the evaluation of the musculoskeletal system, including wideband Doppler imaging, spatial compound imaging,
extended field-of-view imaging, steering-based
gray-scale imaging, elastography and 3D imaging.
Because these new imaging procedures are many
and characterized by different names depending on
the manufacturer – so that considerable confusion
may exist regarding how they work and how they
7
Technical Requirements
Different from conventional B-mode in which the US
images are obtained from a single angle of insonation
(perpendicular to the transducers array), in compounding mode the digital beam-former steers the
US beam at several (up to nine) steering angles during
real-time acquisition rates (Claudon et al. 2002).
When the signal is received, the lines of sight are rendered according to the rectangular geometry of the
field-of-view of the US image. The advantages of compound mode are many, including reduction of image
artifacts (e.g., speckle, clutter, noise, angle-generated
artifacts), sharper delineation of tissue interfaces and
better discrimination of lesions over the background
as well as improvement in detail resolution and image
contrast. In the musculoskeletal system, compound
imaging leads to an improved delineation of structures composed of specular echoes, such as tendons
and muscles (Lin et al. 2002). This derives from the
fact that, when these structures are imaged, the highest echo amplitude is obtained at the point at which
the US beam is perpendicular to them as a result
of anisotropy (i.e., fibrillar echotexture of tendons,
curved surfaces). With spatial compounding, images
are generated from different view angles: therefore,
the likelihood is greater that one of these angles will
be perpendicular to the tendon or the muscle fibers to
generate a higher echo amplitude even at insonation
angles that cause anisotropy on conventional mode
(Fig. 1.6a) (Lin et al. 2002). Edge shadows resulting
from the boundaries of subcutaneous fat lobules,
tendons, muscles, nerve fascicles, fascial planes and
vessel walls are also erased because they reflect only
weakly at oblique angles (Fig. 1.6b–e) (Claudon et
al. 2002). Another advantage of compound imaging is reduction of speckle noise, a random artifact
causing a grainy appearance of the US images as
a result of scattering from tissue reflectors (Lin et
al. 2002). Speckle reduction obtained by averaging
frames from different angles of insonation leads to
improved image definition and better signal-to-noise
ratio. The resulting image appears smoother with
better tissue-plane definition. Compounding with a
high number of averaged frames worsens temporal
resolution (Lin et al. 2002): this does not seem to be
a problem in musculoskeletal US as the examination
is free from respiratory and cardiac motion and, in
most cases, static. In general, dynamic maneuvers
during passive tendon or joint movement are not
significantly affected by frame averaging. Recently,
some compound mode systems have been developed
using simultaneous emission of two different frequencies instead of one to improve contrast resolution (transmit frequency compound). Adaptive algo-
rithms which perform real-time analysis of patterns
at pixel level and refine the image by emphasizing
patterns within the tissue texture and de-emphasizing artifacts and noise, can be combined with spatial
compound imaging to further sharpen borders and
tissue interfaces. Similarly, color B-mode imaging
systems with contrast optimization (photopic imaging) can be applied to improve overall image contrast
and definition of deep soft-tissue boundaries (Sofka
et al. 2005).
1.1.2.3
Extended Field-of-View Imaging
One of the main drawbacks of linear-array transducers to image the musculoskeletal system is the
limited extension of the field-of-view (often < 4 cm
wide). With these probes, displaying the full extent
of an abnormality and showing its relationship with
adjacent structures on a single image may be problematic: this creates inadequate reproduction of the
full lesion on prints and difficulties for colleagues and
the referring physician when reading the US images.
Somewhat similar to the compound systems produced
in the middle and late 1970s, extended field-of-view
technology uses specific image registration analysis
to track probe motion and reconstruct a large composite image during real-time scanning over long
distances and curved body surfaces without using
external positional devices. After selecting a scanning plane of interest, the examiner slides a standard
probe along the skin surface in the direction of the
scan plane while monitoring the image on the screen.
During lateral probe motion, there is an advancing
real-time portion of the image and a static portion
which displays what has been scanned (Fig. 1.7).
The reconstruction process is based on the fact that
image features of a given frame and the next frame are
very similar, except that the second image is slightly
shifted or rotated relative to the first one (Weng et al.
1997). Successive frames are registered and blended
with the previous ones based on an autocorrelation
algorithm and an advanced parallel processing architecture requiring intense digital work. As determined
on phantoms, geometric measurement of extended
field-of-view US is accurate to within < 5% (Weng
et al. 1997; Fornage et al. 2000). Particularly in the
examination of the musculoskeletal system, this technique seems able to provide accurate data because of
the absence of respiratory movements or pulsatility
of large vessels (Weng et al. 1997; Barberie et al.
1998; Lin et al. 1999). Extended field-of-view imag-
9
10
L. E. Derchi and G. Rizzatto
a
b
c
d
e
Fig. 1.6a–e. Spatial compound imaging. a Schematic drawing illustrates the image acquisition process in compound mode. The
US beam is steered out of axis providing multiple lines of sight at several angles during real-time acquisition. Signal processing
renders the steered frames into a final image in real time as each new frame is acquired. With this system, a clearer delineation of
borders (in black) and interfaces is obtained even when they are oriented at unfavorable angles. The acoustic shadow posterior to
calcifications is usually thinner and less delineated than in the conventional mode. b,c Conventional cross-sectional b 12–5 MHz
and c 17–5 MHz images of the median nerve at the mid-forearm. Deep to the flexor carpi radialis tendon (arrowheads), the
nerve (arrow) appears as a rounded structure composed of many small hypoechoic dots related to the fascicles. Note how the
fascicles are more clearly depicted as the frequency increases. The muscle tissue of the flexor digitorum profundus (dashed
square) appears coarse and grainy. d,e Corresponding d 12–5 MHz and e 17–5 MHz compound images. The fascicles are better
delineated compared with the images acquired in conventional mode. The best result is obtained with the combined use of
spatial compounding and the 17–5 MHz US probe. Muscles (dashed square) exhibit a more homogeneous echotexture as a result
of better suppression of speckle artifact and an increased signal-to-noise ratio. Example of SonoCT Imaging (Philips)
Technical Requirements
Fig. 1.7a–c. Extended field-ofview imaging. a–c Formation
of a panoramic extended fieldof-view image over the gluteus
minimus muscle (arrowheads).
During real-time scanning,
the probe is moved caudally
(arrows). The box indicates
where the current frame is
obtained. Image frames are
translated and rotated according to the estimated probe
motion by means of image
registration. The final panoramic image shows the whole
length of the gluteus minimus
from the iliac crest (Ic) to its
insertion into the great trochanter (Gt). The relationships
of the gluteus medius tendon
(open arrows) with the gluteus
minimus tendon (white arrow)
are shown. The photographs at
the upper left side of the figures indicate probe positioning. Example of Extended-FOV
Imaging (Siemens)
a
b
c
ing can show the abnormality (most often large fluid
collections, muscle injuries, tumors, etc.) in association with the appropriate landmarks, such as joints,
tendons and muscles, which may even be remote
from the structure of interest. Although training is
important to obtain accurate images, the extended
field-of-view technique contributes to an improved
presentation of the US information for the referring
physician (Weng et al. 1997; Barberie et al. 1998;
Lin et al. 1999; Sauerbrei 1999).
1.1.2.4
Steering-Based Imaging
In addition to spatial compound and Doppler
systems, the beam steering function has recently
been applied to B-mode imaging to obtain a parallelogram format with lateral sides parallel but
oblique instead of a rectangular field-of-view. This
function is obtained by activating consecutive ele-
ments in the array with increasing delays so that a
wavefront resulting from constructive interference
sends oblique lines-of-sight along the depth axis.
In musculoskeletal US, this function seems to be
useful when anisotropic structures, such as tendons
or ligaments, are examined with an incidence angle
far from 90° due to their oblique course from surface
to depth (distal biceps tendon, Achilles and supraspinatus tendon insertion, etc.). Beam steering may
optimize depiction of the fibrillar echotexture in
an otherwise hypoechoic tendon area, thus helping to avoid confusion between artifact and disease (Fig. 1.8). Given that many pathologies of the
musculoskeletal system are larger than the small
field-of-view of linear-array transducers, a steering
technology (wide field-of-view) able to increase the
lateral size of the image in the far field has been
developed recently. The resultant trapezoid shape
of the field-of-view leads to reproduction of large
lesions in their full extent without the requirement
for extended field-of-view algorithms (Fig. 1.9).
11
12
L. E. Derchi and G. Rizzatto
Fig. 1.8a–d. Beam steering
for gray-scale imaging. a,b
Long-axis 14–7 MHz US
images over the insertion
of the Achilles tendon
(white arrowheads) on the
calcaneus (Ca) acquired
a on conventional mode
and b by steering the
beam (void arrowheads)
to produce an oblique
wavefront. In b, note suppression (open arrow) of
the artifactual hypoechoic
intratendinous area (white
arrow) due to steering
the beam perpendicularly
to the tendon insertion.
c,d Correlative schematic
drawings. Example of
B-mode steering function
(Toshiba)
Ca
c
a
Ca
d
b
a
c
b
d
VL
VM
e
Fig. 1.9a–e. Wide fieldof-view technology. a,b
Transverse 12–5 MHz US
images over the anterior
thigh with c,d schematic
drawing correlation in a
25-year-old patient who
suffered a strain injury of
the distal aponeurosis of
the rectus femoris muscle
resulting in an extensive
peripheral hematoma
(white arrows). a Using a
conventional rectangular
field-of-view, the hematoma cannot be displayed
in its full extent: part of
it (arrowheads) is out
of the field-of-view of
the US image. b With a
trapezoidal field-of-view,
the full width of the
hematoma is depicted,
including its more lateral
portion (open arrows).
Curved arrow, central
aponeurosis. e Corresponding extended
field-of-view imaging
obtained on a transverse
plane over the anterior
thigh. In the panoramic
view, the relationships
of the muscle injury
with adjacent anatomic
landmarks, including the
vastus lateralis (VL) and
the vastus medialis (VM),
are shown. Example of
Wide-FOV (Philips)
Technical Requirements
1.1.2.5
Three-Dimensional Imaging
The improvement in fast digital computer processing and memory storage capacity has recently
improved the possibility of applying 3D technology to US (Brandl et al. 1999; Wallny et al.
2000; Claudon et al. 2002). Three-dimensional
acquisition can be achieved with US using either
2D conventional transducers equipped with a
small electromagnetic positional sensor or dedicated “3D-volume transducers,” which are larger
than standard probes and more difficult to handle
but have the advantage of providing more exact
assessment of each scanning plane (Fig. 1.10). These
latter transducers sweep the US beam throughout
the tissue volume by tilting the scan-head with a
mechanized drive along the z-axis. During this
procedure, serial slices are recorded resulting in
a pyramid-shaped volume scan: for each slice, the
angle between slices is known, minimizing distortion in the final image. Following volume scan
acquisition, the monitor displays reconstructed
slices according to longitudinal, transverse and
coronal planes. Each plane can be oriented within
the volume block for detailed analysis by parallel or rotational shifting around any of the three
spatial axes (Brandl et al. 1999). Data can also
be displayed as true 3D images using various rendering algorithms, including maximum intensity
projection, transparent, surface and Doppler renderings (Brandl et al. 1999). Recently, volume
transducers in the frequency range suitable for
analysis of the musculoskeletal tissue have been
introduced, opening new interesting perspectives
for evaluation of a variety of disorders, including
rotator cuff tears, infant hip, congenital clubfoot
and bone lesions (Gerscovitch 1997; Wallny et
al. 2000; Hünerbein et al. 2001). As well as dedicated systems, software programs for 3D rendering
of power Doppler images are now available in many
scanners, involving capture of a series of sequential
images while the transducer is translated manually without the necessity for specific hardware.
Although some inaccuracies occur if the motion is
not uniform, the available technology seems able
to produce vascular images of acceptable quality in
the musculoskeletal system (Doria et al. 2000).
M
M
M
*
M
*
a
M
b
c
*
M
*
d
Fig. 1.10a–d. Three-dimensional imaging. a Schematic drawing of a coronal view through the metatarsal bones demonstrates a
conventional 2D scanning plane obtained along the x-axis (coronal) by placing the probe over the dorsal forefoot. b Corresponding drawing shows a reconstructed plane oriented over the z-axis (axial) by means of 3D technology. c,d Three-dimensional
volume acquisitions over the forefoot using a high-frequency dedicated probe. Conventional US scans (upper images) reveal
the metatarsal bones (M) as hyperechoic images with posterior acoustic shadowing. With 3D imaging, two reconstructed axial
planes (lower images) have been obtained at the level of c the subcutaneous tissue and d the metatarsal bones according to the
white bars shown in the upper images as reference. In c, the fat globules appear as confluent hypoechoic areas embedded in a
homogeneous hyperechoic background; in d, the metatarsals (M) and the interosseous muscles (asterisks) are displayed in their
long axis. Example of 3D-Voluson Technology (General Electric)
13
14
L. E. Derchi and G. Rizzatto
1.1.2.6
Elastographic Imaging
In many clinical settings, physical examination provides essential information in detecting abnormalities and monitoring changes related to worsening or
healing of disease. Manual palpation is part of the
physical examination, with the aim of providing
qualitative assessment of changes in tissue softness/
stiffness that often accompany pathologic states.
Generally speaking, findings at palpation depend
on the difference in stiffness between normal and
pathologic tissues based on their histologic composition and supramicroscopic architecture. In many
instances, however, the lesion may lie too deep or be
too small to be detected by palpation despite a large
difference in stiffness with the surrounding tissues.
For these reasons interest is growing in developing
methods for recognizing abnormal tissues based on
shear elastic properties (Bamber 1999). US-based
elastography measures tissue displacement (strains)
responses to an external force on the assumption that
the strain is smaller in harder than in softer tissues.
The method is based on comparison of US radiofrequency waveforms obtained before and after light
tissue compression with a conventional probe using
a free-hand technique (Itoh et al. 2006). Analysis of
strain is based on automated segmentation of continuous US images obtained during tissue compression. Color pixels are assigned to the elastographic
image depending on the magnitude of strain, with a
scale range from red (soft components) to blue (stiff
components). In the musculoskeletal system, preliminary experience indicates that elasticity assessment may be promising to separate structures (i.e.,
degenerated from partially torn tendons) that are
indistinguishable on gray-scale US imaging, as well
as to disclose occult disease in otherwise normalappearing tissue, such as compartment syndromes
(Fig. 1.11). It is obvious that lesions containing fat,
fluid or synovium will be softer than fibrotic and
collagen-containing disease processes. With future
improvements in technology and experience, we
expect that elastography will become an important
tool for the diagnosis of musculoskeletal disorders
in selected clinical settings.
1.1.3
Ultrasound Contrast Media
The ability of US to enhance detection of blood flow
with echo reflectors after the injection of a vari-
ety of fluids was first described approximately 40
years ago (Gramiak and Shah 1968). Once it was
found that the source of the additional intravascular echoes was related to microbubbles developing
during the injection process, the pharmaceutical
industry started to develop stabilized microbubble
preparations to be injected into the venous system
in a safe way that would cross the pulmonary capillary bed and provide vascular enhancement for the
whole duration of the clinical study. The technology used has been that of encapsulated bubbles of
gas, smaller in size than the red blood cells: several
gases have been used, ranging from air to less diffusible drugs, such as sulfur hexafluoride or perfluorocarbons. The gas was appropriately encapsulated
in phospholipid shells of different thickness and
stiffness to obtain stability and duration over scanning. US contrast agents serve as an active source
of sound reflectors creating an echogenic pattern in
the flowing blood. In pharmacologic terms, microbubble-based contrast agents are considered “blood
pool agents” until metabolized, as they are neither
filtered by the kidney nor able to enter the interstitial
spaces: some have recently been shown to exhibit
specific uptake in the liver and spleen after their loss
from the blood pool. When microbubbles are contacted by a high-intensity high-pressure US beam,
they collapse producing a transient strong broadband signal; on the other hand, when the intensity
of the US beam is low, microbubbles oscillate in the
US field and undergo a process of resonation, rapidly
contracting and expanding in response to pressure
changes of the US wave, emitting a spectrum of harmonic signals.
Specific US techniques have been developed to
detect signals from microbubbles, including multipulse coded-emission modes and the so-called pulse
or phase inversion in which consecutive pulses of
opposite phase are transmitted along the same line:
the signal subtraction leads to a relative increase
in the nonlinear response from tissues by deleting
the response from static structures which intrinsically have minor nonlinear components. In practice,
two main imaging strategies are followed to optimize the microbubble response. With “destructive
modes” (high mechanical index imaging), the signal
derives from microbubble destruction produced by
high-intensity US peaks: time intervals are needed
for contrast replenishment between scans; with
“non-destructive modes” (low mechanical index
imaging), the harmonic response is collected from
microbubble insonation at low-intensity US emission providing continuous imaging of microvessel
15
Technical Requirements
Gt
Gt
a
b
Gt
Gt
c
d
Fig. 1.11a–d. Elastographic imaging. Two different patients with shoulder impingement syndrome presenting with a,b cuff tendinosis and c,d supraspinatus tendon tear. a Long-axis gray-scale 13–6 MHz US image over the supraspinatus demonstrates a
slightly swollen but intact tendon (arrows) associated with thickened bursal walls (arrowheads). Both structures are hypoechoic
and cannot be clearly separated. Gt, greater tuberosity. b Corresponding elastographic image helps to distinguish the bursa
from the underlying tendon on the basis of its greater compressibility. c Long-axis gray-scale 13–6 MHz US image over a torn
and retracted supraspinatus shows residual hypoechoic bursal tissue and fluid (arrowheads) over the humeral head. d On the
elasticity image, this tissue is compressible (imaged in red): this finding may help to distinguish it from residual intact tendon
fibers. Gt, greater tuberosity. Example of Real-time Tissue Elastography (Hitachi)
perfusion (Claudon et al. 2002). Based on the latest
advances, both techniques make use of gray-scale
(and not Doppler) imaging to optimize detection of
contrast enhancement. At present, the clinical use of
US contrast agents is expanding but the experience
is referred, in most cases, to abdominal applications.
This is related to the fact that imaging of superficial
tissues requires too high a transducer frequency
band to induce a discrete harmonic response from
the microbubbles. Recently, dedicated probes for
use in contrast studies in superficial tissues and
organs have overcome this limitation, leading to
encouraging results in imaging arthritis and other
rheumatologic conditions (see Chapter 5) (Klauser
et al. 2005).
References
Bamber JC (1999) Ultrasound elasticity imaging: definition
and technology. Eur Radiol 9:327–330
Barberie JE, Wong ADW, Cooperberg PL et al (1998) Extended
field-of-view sonography in musculoskeletal disorders. AJR
Am J Roentgenol 171:751–757
Brandl H, Gritzky A, Haizinger M (1999) 3D ultrasound: a
dedicated system. Eur Radiol 9:331–333
Claudon M, Tranquart F, Evans DH et al (2002) Advances in
ultrasound. Eur Radiol 12:7–18
Doria AS, Guarniero R, Molnar LJ et al (2000) Three-dimensional (3D) contrast-enhanced power Doppler imaging in
Legg-Calvè-Perthes disease. Pediatr Radiol 30:871–874
Entrekin RR, Porter BA, Sillesen HH et al (2001) Real-time
spatial compound imaging: application to breast, vascular
and musculoskeletal ultrasound. Semin Ultrasound CT MR
22:50–64
16
L. E. Derchi and G. Rizzatto
Fornage BD, Atkinson EN, Nock LF et al (2000) US with
extended field of view: phantom-tested accuracy of distance measurements. Radiology 214:579–584
Gerscovich EO (1997) A radiologist’s guide to the imaging in
the diagnosis and treatment of developmental dysplasia of
the hip. II. Ultrasonography: anatomy, technique, acetabular angle measurements, acetabular coverage of femoral
head, acetabular cartilage thickness, three-dimensional
technique, screening of newborns, study of older children.
Skeletal Radiol 26:447–456
Gramiak R, Shah PM (1968) Echocardiography of the aortic
root. Invest Radiol 3:356–366
Hünerbein M, Raschke M, Khodadayan C et al (2001) Threedimensional ultrasonography of bone and soft-tissue
lesions. Eur J Ultrasound 13:17–23
Itoh A, Ueno E, Tohno E et al (2006) Breast disease: clinical
application of US elastography for diagnosis. Radiology
239:341–350
Klauser A, Demharter J, De Marchi A et al (2005) Contrast
enhanced gray-scale sonography in assessment of joint
vascularity in rheumatoid arthritis: results from the IACUS
study group. Eur Radiol 15:2404–2410
Lin CD, Nazarian LN, O’Kane PL et al (2002) Advantages of
real-time spatial compound sonography of the musculoskeletal system versus conventional sonography. AJR Am J
Roentgenol 171:1629–1631
Lin EC, Middleton WD, Teefey SA (1999) Extended field of
view sonography in musculoskeletal imaging. J Ultrasound
Med 18:147–152
Rizzatto G (1999) Evolution of US transducers: 1.5 and 2D
arrays. Eur Radiol 9:304–306
Sauerbrei EE (1999) Extended field-of-view sonography: utility in clinical practice. J Ultrasound Med 18:335–341
Sofka CM, Lin D, Adler RS (2005) Advantages of color B-mode
imaging with contrast optimization in sonography of lowcontrast musculoskeletal lesions and structures in the foot
and ankle. J Ultrasound Med 24:215–218
Wallny TA, Theuerkauf I, Schild RL et al (2000) The threedimensional ultrasound evaluation of the rotator cuff: an
experimental study. Eur J Ultrasound 11:135–141
Weng L, Tirumalai AP, Lowery CM et al (1997) US extendedfield-of-view imaging technology. Radiology 203:877–880
Whittingham TA (1999a) An overview of digital technology in
ultrasonic imaging. Eur Radiol 9:307–311
Whittingham TA (1999b) Broadband transducers. Eur Radiol
9:298–303
Skin and Subcutaneous Tissue
General
17
Skin and Subcutaneous Tissue
Skin and Subcutaneous Tissue
Maura Valle and Maria Pia Zamorani
CONTENTS
2.1
Histologic Considerations 19
2.2
Normal US Findings
20
2.3
2.3.1
2.3.2
2.3.2.1
2.3.2.2
2.3.2.3
2.3.2.4
2.3.2.5
2.3.3
2.3.3.1
2.3.3.2
Pathologic Findings 21
Skin Abnormalities 21
Subcutaneous Tissue Abnormalities 22
Edema 22
Cellulitis, Abscess and Necrotizing Fasciitis 23
Fatty Atrophyy 25
Traumatic Injuries 25
Foreign Bodies 27
Tumors and Tumor-Like Conditions 31
Lipomas 33
Pilomatricoma and Epidermal
Inclusion (Sebaceous) Cysts 35
2.3.3.3 Hemangiomas and Vascular Malformations 36
2.3.3.4 Metastases and Lymphomas 38
References
41
2.1
Histologic Considerations
From the histologic point of view, the skin varies in
thickness from 1.5 to 4.0 mm and is composed of a
superficial layer and a deep layer – the epidermis
and the dermis, respectively (Fig. 2.1a). The epidermis is made of stratified epithelium, and can be
divided into two main layers: the superficial stratum
corneum, which is made of closely packed flattened
dead cells, and the deep germinative zone (consisting of the stratum basale, stratum spinosum and
stratum granulosum). In regions that are not subject
to pressure, the epidermis is thin and hairy, whereas
M. Valle, MD
Staff Radiologist, Reparto di Radiologia, Istituto Scientifico
fi
“Giannina Gaslini”, Largo Gaslini 5, 16148 Genova, Italy
M. P. Zamorani, MD
Unité de Recherche et Dévelopement, Clinique des Grangettes,
7, ch. des Grangettes, 1224 Genève, Switzerland
in areas undergoing attrition and local shocks (i.e.,
palms of the hands and soles of the feet), the skin is
hairless and may thicken to an even greater extent
as a result of a hypertrophied stratum corneum.
Deep to the epidermis, the dermis is a thick layer
containing large amounts of collagen and a rich network of vessels, lymphatics and nerve endings. It
can be divided into a deep reticular layer, which is
composed of bulky connective tissue, and a superficial papillary layer, which interdigitates with the
base of the epidermis and provides an important
mechanical and metabolic support to the overlying
epidermis. Additional structures housed within the
dermis are sebaceous and sweat glands, hair follicles
and erector pili muscles.
Deep to the dermis, the subcutaneous tissue lies
between the skin and the fascia (Fig. 2.1a). It acts as
a gliding plane between these structures, thus protecting deeper areas from acute and chronic trauma;
it also stores fat and participates in temperature control. The subcutaneous tissue is formed by a network
of connective tissue septa and fat lobules. The overall
size and extent of these septa vary at different sites
of the body: they may be tiny in “loose” skin or compact when the skin is firmly attached to the underlying fascia. In normal conditions, the thickness of the
subcutaneous tissue varies greatly depending on the
amount of fat contained within. In some areas of the
body, such as the dorsal aspect of the hand, the fat
is sparse, while in other regions, such as the thighs
and the buttocks, it is abundant. The amount and
distribution of subcutaneous fat is also related to the
individual body habitus, sex and the meteorologic
environment. Discrete vessels, lymphatics, sensory
nerve endings and hair follicles are contained in the
subcutaneous tissue.
In areas where moving structures are tightly
apposed, superficial “attritional” bursae separate
the skin from the underlying tissues, and especially
from the bone. These bursae are synovial-lined sacs
tethered by dermis and periosteum. In the fingers
and toes, the nails include the nail plate, the nail
folds, the epidermis, the germinative matrix and the
19
2
20
M. Valle and M. P. Zamorani
a
*
*
c
b
Fig. 2.1a–c. Normal skin and subcutaneous tissue. a Photograph of a cadaveric cross-section of the anterior thigh demonstrates
a superficial
fi
layer refl
flecting the epidermis and dermis (black arrow), an intermediate thick layer representing fat contained
fi
to the quadriceps muscle, due to the
in the subcutaneous tissue (double arrow) and a deep thin layer, located just superficial
juxtaposed superficial
fi
and deep fascia (white arrow). b Corresponding transverse 17–5 MHz US image obtained in a healthy subject demonstrates the three tissue layers shown in a: the epidermis and dermis (black arrow) are homogeneously hyperechoic;
flecting fat lobules (asterisks) and hyperechoic
the subcutaneous tissue (double arrow) includes a hypoechoic background refl
strands (arrowheads) due to connective septa; the apposed superfi
ficial and quadriceps fasciae appear hyperechoic (white arrow).
ficial tissues. From surface downward, note the epidermis and
c Schematic drawing shows the normal architecture of the superfi
dermis (1, 2); the subcutaneous tissue (3) containing fat lobules (asterisks) separated by connective tissue strands (arrowheads);
the superficial
fi
and deep (muscle) fascia (4-5); and the muscles (6)
dermis. The nail plate is similar to the stratum corneum of the skin. The proximal nail plate and the
lateral folds overlie its sides. The undersurface of the
nail plate is lined by squamous epithelium, which is
continuous with that of the proximal nail fold and
thickens at the nail root to form the germinative
matrix.
2.2
Normal US Findings
US of the skin is almost exclusively performed by
dermatologists, who make use of dedicated equipment with ultra-high-frequency transducers working at 20–100 MHz. Although the in-plane resolution
of these transducer is as high as <50 μm, the depth
of field is markedly limited at such high frequencies,
and is reported to be 1 mm or less (Erickson 1997).
Therefore, these transducers are not suitable for a
combined evaluation of the subcutaneous tissue in
its full thickness. At 20 MHz, the echogenic dermis
can be distinguished from the hypoechoic subcuta-
neous fat and pilosebaceous units are recognizable
(Fornage et al. 1993). The thick epidermis of the
palm and sole can be recognized as well. In sites
covered by thin hairy skin, the epidermis can be
appreciated as an individual structure by means
of 40 MHz frequency transducers. In aged skin, a
subepidermal low-echogenic band is often appreciated as a result of increased water content. Normal
skin thickness ranges have been established with
US at different body sites (Fornage and Deshayes,
1986; Fornage et al. 1993). Further details on the
US examination of the skin are beyond the scope
of this chapter.
An adequate assessment of the subcutaneous
tissue can be efficiently performed be means of “less
specialized” high-resolution transducers characterized by the same frequency range (5–15 MHz) appropriate for other musculoskeletal examinations. The
type and frequency of the selected transducer vary
depending on the region of the body to be examined.
For the thin subcutaneous tissue of the dorsum of the
hand and wrist, linear-array transducers working at
a center frequency >7.5–10 MHz are the most appropriate. Superficial focusing capabilities and a thin
21
Skin and Subcutaneous Tissue
stand-off pad are additional requirements. On the
other hand, if the thick subcutaneous fat of the lateral part of the proximal thigh is the target of examination, US should be performed at lower frequencies,
even as low as 5 MHz if needed, to obtain sufficient
penetration for a reliable assessment. A large amount
of gel that produces a homogeneous, uniform contact between probe and skin may be required to
avoid formation of small air bubbles. Examination
of certain body areas, such as the plantar aspect of
the calcaneus, can be difficult to perform because
the thickened stratum corneum can cause considerable US beam attenuation, leading to a decreased
signal-to-noise ratio of the US image. The subcutaneous tissue appears at US as a discrete hypoechoic
layer characterized by a hypoechoic background of
fat and hyperechoic linear echoes corresponding
to a web of connective septa (Fig. 2.1b). These septa
run, for the most part, parallel or slightly obliquely
to the skin surface. Subcutaneous veins are displayed as elongated or rounded echo-free structures
that run inside the larger septa. Owing to their low
blood pressure, normal veins collapse if pressure is
applied over them with the probe. In selected cases,
color Doppler imaging can be used to demonstrate
blood flow signals within the vessels. Small sensory
nerves can be appreciated as very tiny fascicular
structures coursing alongside the largest superficial
veins (Fig. 2.2). Both veins and sensitive nerves usually run in the deep part of the subcutaneous tissue.
Knowledge of the close relationship of nerves with
adjacent veins makes their detection easier: the sural
nerve, for instance, can be easily detected at the posterior distal leg because it is satellite to the adjacent
small saphenous vein. Lymphatics housed within
the connective septa cannot be visualized with US,
unless distended by fluid as in the case of subcutaneous edema. Dynamic US examination while applying
either different degrees of pressure with the probe or
finger palpation or manual mobilization of the skin
is essential for evaluating masses, fluid collections
and fibrosis of the subcutaneous tissue.
2.3
Pathologic Findings
2.3.1
Skin Abnormalities
A detailed description of the US findings observed
in the wide range of pathologic conditions affecting
the skin is beyond the scope of this chapter. Briefly,
the use of specialized 20–50 MHz transducers has
been mainly proposed in the following settings:
measurement of the thickness and depth of skin
tumors prior to cryosurgery, laser surgery or radiotherapy; and monitoring the effects of therapy in
chronic inflammatory processes, such as psoriasis
(Schmid-Wendtner and Burgdorf 2005).
Skin tumors appear as focal hypoechoic nodules, clearly distinguishable from the surrounding
normal dermis because of the higher echogenicity
of the latter. In most cases, including melanomas,
the lateral boundaries of the tumor are ill defined,
whereas there is a clear-cut basal demarcation. It has
been reported that in the assessment of melanoma
thickness the accuracy of US is comparable to that
of histology. In tumor staging, the main limitations
of US are related to overestimation of the tumor size
due to either surrounding inflammatory infiltration
Muscle
a
b
Fig. 2.2a,b. Subcutaneous veins and nerves. a Transverse 12–5 MHz US image obtained over the posterior calf demonstrates
the small saphenous vein (white arrowhead) and the adjacent sural nerve (black arrowhead) running in the deep subcutaneous
tissue. Detection of the larger vein is a useful landmark for recognition of the smaller nerve. Arrows indicate the fascial plane.
b Schematic drawing correlation shows subcutaneous veins (white arrowheads) and the nerve (black arrowhead) coursing in
the connective spaces which separate fat lobules
22
M. Valle and M. P. Zamorani
which, being hypoechoic, cannot be discriminated
from neoplastic tissue, or inclusion of other structures (i.e., hair follicles and sweat glands) as part
of the lesion itself. These errors are less frequent
in the evaluation of advanced-stage tumors, when
peritumoral inflammatory infiltration is generally
less conspicuous (Fig. 2.3a). In addition, a precise
demarcation of the tumor from the subcutaneous
fat is often unfeasible in tumors extending deep
to the dermis-subcutaneous separation plane due
to their similar hypoechoic echotextures. Overall,
the diagnostic value of US for staging skin tumors
has been significantly downgraded in recent years
and relegated to restricted use in a few specialized
dermatologic centers. In contrast, in the postoperative follow-up of patients with melanoma, US has
proved helpful in guiding the management strategy
of the referring physician by facilitating detection
of nonpalpable metastases occurring in the area of
the original scar or skin graft or along the pathway
of lymphatic drainage. In addition, US may add as
well as in differentiating benign from malignant
palpable masses by guiding definitive biopsy, and
in the assessment of pharmacodynamic response to
chemotherapy (Nazarian et al. 1996).
Among non-neoplastic conditions, cutaneous
scars appear as ill-defined focal hypoechoic bands
with posterior acoustic shadowing usually extending
into the subcutaneous tissue with a definite straight
course (Fig. 2.3b). The examiner should be aware
of the appearance of superficial scars because they
*
*
may indicate the site and path of previous surgery
or penetrating wounds. In scleroderma, the measurement of skin thickness by high-resolution US in
clinically involved and non-involved areas can support an early diagnosis. In this setting, US may allow
detection of the different stages of disease (Akesson
et al. 1986; Scheja and Akesson 1997; Brocks et al.
2000; Clements et al. 2000).
2.3.2
Subcutaneous Tissue Abnormalities
2.3.2.1
Edema
US demonstrates subcutaneous edema as a hyperechoic appearance of fat lobules. In the early stages,
oedematous changes tend to involve the deep layer of
the subcutaneous tissue, which becomes hypoanechoic due to fluid accumulation related to dilation
of lymphatics, whereas the most superficial layers of
the subcutaneous tissue retain a normal appearance
(Fig. 2.4a,b). With progressive accumulation of fluid,
the connective septa enlarge and become anechoic
strands as a result of distension of the superficial
network of lymphatic channels, until the fat lobules
become individualized structures separated from
one another by anechoic fluid (Fig. 2.4c-e). One should
realize that the fluid that surrounds the lobules is
not free but contained within dilated lymphatic
*
*
Muscle
a
b
Fig. 2.3a,b. Skin abnormalities. a Mycosis fungoides/Sézary syndrome. A 15-10-MHz US image over a skin papula in the anterior
abdominal wall demonstrates a superfi
ficial ill-defi
fined hypoechoic tumor (asterisks) with signs of infiltration
fi
of the subcutaneous fat (arrowheads). Arrows, fascial plane. b Postoperative scar. Transverse 12–5 MHz US image over the lateral thigh in a
patient who underwent previous resection for a liposarcoma shows a hypoechoic straight band (black arrow) extending with
flecting a postoperative scar. Note that the hypoechoic band is surrounded by a
a vertical course from the skin downward, refl
peripheral hyperechoic halo (arrowheads) refl
flecting fibrotic changes in the adjacent subcutaneous (asterisks) and underlying
muscle (white arrow)
Skin and Subcutaneous Tissue
*
*
b
*
*
d
*
c
*
e
Fig. 2.4a–e. Subcutaneous tissue edema. a Schematic drawing illustrates the arrangement of fl
fluid-fi
filled dilated lymphatic channels (in black) within the subcutaneous tissue in cases of noninfl
flammatory edema. Lymphatic vessels travel in the hyperechoic
connective tissue septa (arrowhead) among fat lobules (asterisks). Once these vessels are distended, they make these septa
thickened and hypoechoic. b Mild subcutaneous edema. Transverse 12-5-MHz US image over the pretibial region shows an increased echogenicity of fat lobules (asterisks) and fluid distention of the lymphatics running in the deep connective septa (black
arrowhead). Note the normal appearance of the more superfi
ficial connective septa (white arrowhead). c Transverse 17-5-MHz
US extended-fi
field-of-view image of the anteromedial knee with correlative d T1-weighted and e T2-weighted MR images in a
patient with severe local subcutaneous tissue edema demonstrates striking enlargement and fluid distension of all septa (open
arrowheads) of the subcutaneous tissue, reflecting
fl
overt dilation of lymphatic channels. Note the fat lobules (asterisks), which
appear as individual structures separated by the intervening fl
fluid. Arrow
w indicates a patent superfi
ficial vein
channels. These findings are typically encountered
in deep venous thrombosis or in local fluid collections. Graded pressure applied with the probe
does not cause collapse of the anechoic strands.
In selected cases, Doppler imaging can differentiate edema within the lymphatics from the adjacent
enlarged subcutaneous veins.
2.3.2.2
Cellulitis, Abscess and Necrotizing Fasciitis
Subcutaneous infections, which are referred to as
cellulitis or panniculitis, are commonly encountered in clinical practice and properly assessed at
physical examination. In most instances, the causative agents of cellulitis are group A Streptococcus
pyogenes or Staphylococcus aureus. In these cases,
US may have an important diagnostic value, especially for differentiating cellulitis from an abscess
and distinguishing the latter from other softtissue masses (Chau and Griffith 2005). US can
stage local spread of infection to deep tissue layers
(involvement of muscles, bursae, tendon sheaths
and joints), and can identify possible causative factors (e.g., foreign bodies, retained gauzes). In addition, it provides accurate guidance for diagnostic
or therapeutic aspiration procedures (Chau and
Griffith 2005). In cellulitis, US demonstrates an
irregular ill-defined hyperechoic appearance of fat
with blurring of tissue planes, progressing to hypoechoic strands reflecting edema (Nessi et al. 1990;
Robben 2004). This appearance is nonspecific and
cannot be distinguished from noninfectious causes
of soft-tissue edema on the basis of echotextural
findings alone (Struk et al. 2001; Robben 2004).
23
24
M. Valle and M. P. Zamorani
Color and power Doppler imaging may help the
clinical diagnosis by depicting a hypervascular pattern in cellulitis (Cardinal et al. 2001) (Fig. 2.5a,b).
Phlebitis and occlusion of superficial veins may also
be observed as associated findings. If untreated,
infectious cellulitis can progress to abscess formation (Fig. 2.5c,d).
In most cases, a subcutaneous abscess is demonstrated as an irregular fluid-filled hypoechoic area
with posterior acoustic enhancement, containing variable amount of echogenic debris (pus) (Fig. 2.5c,d).
Fluid-fluid levels within the collection with dependent layering of the more echogenic particulate material can be noted. In highly echogenic collections,
a slight pressure with the probe or the fingers may
help to confirm the liquid nature of the mass by causing fluctuation of the particles (Loyer et al. 1996).
Doppler imaging modalities typically show hyperemic blood flow within the abscess wall and the surrounding tissues (Arslan et al. 1998). Cellulitis being
essentially a clinical diagnosis, the main diagnostic
role of US is to rule out deep venous thrombosis and
*
*
*
a
*
b
*
*
*
*
*
c
d
Fig. 2.5a–d. Subcutaneous tissue infection. a,b Cellulitis and c,d abscess. Images are from different patients. a Color Doppler
fi
12–5 MHz US image reveals a diffusely increased echogenicity of the subcutaneous fat (asterisks) with blurring of the definition
of connective septa and fatty lobules, and an increased vasculature. b Color Doppler 12–5 MHz US image shows signs of initial
progression of cellulitis into abscess. There is diffuse subcutaneous edema with hyperechoic fatty lobules (asterisks) alternating
with irregular hypoechoic areas (arrowhead) filled with Doppler signals. An intense hypervascular pattern is seen. c Gray-scale
12–5 MHz US image over the gluteal region in patient with tuberculosis demonstrates coalescence of hypoechoic serpiginous
areas into a large hypoechoic abscess (asterisk) with loss of Doppler signals. d Power Doppler 12–5 MHz US image of a forearm
abscess in an HIV-positive patient shows a large cavity fi
filled with echogenic particulate material (asterisk) inside the subcutaneous tissue, displacing the fat lobules. Fluctuation of the echogenic material filling the abscess could be obtained on compression.
The abscess dislocates and stretches the connective septa and the small vessels (arrowheads) contained within them.
25
Skin and Subcutaneous Tissue
to identify an underlying abscess. Even if an abscess is
not found but infection-related symptoms persist, US
examination should be repeated because liquefaction
may manifest with time (Robben 2004). In addition,
if the abscess lies in proximity to the bone, US may
reveal the osseous origin of the infection by depicting
hypoechoic subperiosteal fluid (Robben 2004).
Often associated with a previous trauma (e.g.,
open wound, insect bite), necrotizing fasciitis is a
rare, rapidly progressive, life-threatening infection
involving the subcutaneous tissue, fascia and surrounding soft-tissue structures, including muscles.
A variety of aerobic and anaerobic bacteria may be
involved as causative agents of necrotizing fasciitis,
group A Streptococcus being the most common. In
most cases, the patient is diabetic, immunocompromised or severely ill with profound toxicity. Although
US is not rewarding at the early stages of infection
when soft-tissue abnormalities may mimic cellulitis, it may be helpful for demonstrating the extent of
fascial thickening and accumulation of cloudy fluid
along the deep fascial layer (Fig. 2.6a). An amount
of fluid >4 mm in depth has been regarded as highly
sensitive and specific for the diagnosis of necrotizing
fasciitis (Yen et al. 2002). In addition, US can reveal
loculated abscesses in the fascial plane – allowing
US-guided diagnostic aspiration – and gas formation
in soft tissues in advanced disease (Robben 2004;
Wilson 2004). Gas gangrene, which is produced by
organisms of bowel origin or by Clostridium, is an
ominous sign (Fig. 2.6b). Aggressive surgical debridement and a course of broad-spectrum antibiotics
are critical for the patient’s survival.
2.3.2.3
Fatty Atrophy
Focal reabsorption of the subcutaneous tissue and
depigmentation of the overlying skin can be observed
following local inadvertent injection of long-acting
corticosteroids (Canturk et al. 2004). This “sideeffect” is somewhat related to the catabolic effect
of the drug: thinning of the subcutaneous fat is
dose-related, may be appreciated up to complete
reabsorption of the fatty tissue layer and shows a
maximal decrease 4–8 weeks after a single injection of steroids (Gomez et al. 1982). US is a reliable
means to confirm the presence of focal shrinkage of
the subcutaneous fat by comparing the affected side
with either the contralateral healthy side or an adjacent normal area. In clinical practice, focal areas of
subcutaneous atrophy may occur around the radial
head following steroid injection for treatment of
tennis elbow and at the buttock secondary to intramuscular injections. Although the US appearance of
subcutaneous atrophy is rather specific, awareness
of the clinical history is essential to correlate the US
findings with a specific causative factor.
2.3.2.4
Traumatic Injuries
In a traumatic setting, and especially in contusion
traumas, changes of the subcutaneous tissue are
commonly encountered. Depending on the strength
and duration of the insult and the patient’s state
a
b
Fig. 2.6a,b. Necrotizing fasciitis. Transverse 12–5 MHz US images over the lower anterolateral leg in a severely compromised
diabetic patient with necrotizing fasciitis demonstrate accumulation of fluid along fascial planes (arrows) and scattered bright
foci in the soft-tissues refl
flecting initial gas formation (arrowheads)
26
M. Valle and M. P. Zamorani
(anticoagulation therapy, steroids, etc.), soft-tissue
abnormalities may range from simple hemorrhagic
infiltration of fat lobules, to fat necrosis, hematomas
and abscesses. US reveals bloody fat infiltration as
an increased echogenicity of fatty lobules that can
make the separation from the hyperechoic skin and
the connective tissue strands of the subcutaneous
tissue undefined (Fig. 2.7a). Hemorrhagic fat infiltration can be readily distinguished from simple edema
because of the absence of anechoic fluid distending the connective septa. The differential diagnosis
with a superficial hyperechoic lipoma is based on
the clinical history and the oval, well-circumscribed
appearance of the soft-tissue mass. Following a contusion trauma, subcutaneous fat necrosis may arise
with edema, hemorrhage and fibrosis with lack of a
discrete soft-tissue mass and volume loss of the subcutaneous tissue (Tsai et al. 1997; Ehara 1998). Fat
necrosis appears as a hyperechoic focus containing
hypoechoic spaces related to infarcted fat (Fernando
et al. 2003) (Fig. 2.7b). In hematomas, the US appearance of the bloody collection varies over time. Soon
after the blood leakage, fresh fluid may appear highly
reflective up to a pseudosolid appearance because of
fibrin and erythrocytes forming multiple acoustic
interfaces. With time, the hematoma tends to become
completely anechoic as a result of liquefaction of the
clot and increases in size (Fig. 2.8a). A network of
thin strands may often be seen resulting from fibrin
organization (Fig. 2.8b). Fluid levels reflecting separation between serum (anechoic) and cellular com-
a
*
ponents (echogenic) of blood can also be observed.
Over a period of months, the hematoma eventually
resolves, but a residual fibrous scar and focal retraction of the overlying skin may persist (Fig. 2.8c). As
described in Chapter 12, a hematoma that has a peculiar disposition related to the subcutaneous tissue is
the Morel-Lavallée lesion. This condition indicates
a post-traumatic seroma which derives from local
trauma usually located over the lateral aspect of the
proximal thigh. The collection typically intervenes
between the deep layer of the subcutaneous tissue
and the fascia as a result of a shear strain mechanism
causing disruption of the rich vascular plexus that
pierces the fascia lata (Morel-Lavallée 1863). US
depicts a Morel-Lavallée lesion as an elongated fluid
collection overlying the straight echogenic appearance of the fascia (Parra et al. 1997; Mellado
et al. 2004). In cases of an abscess secondary to
trauma, the examiner should attempt to recognize
any possible foreign body within it as the causative factor (Fig. 2.9). This is valid even if the patient
denies previous open wounds, because the presence
of foreign bodies requires surgical removal. In an
effort to exclude a more extensive spread of infection that may deserve different treatment, the examiner should check the status of underlying regional
muscles, tendon sheaths and joint spaces. Finally, a
contusion trauma on the skin by a pointed, sharp
object can be transmitted to the subcutaneous tissue
causing laceration and focal discontinuity of fat lobules. This category of lesions results in “fat fractures”
*
Fig. 2.7a,b. Subcutaneous tissue contusion trauma and fat necrosis. a Transverse extended-fi
field-of-view 12–5 MHz US image of
the trochanteric region in a patient with local contusion trauma after a fall demonstrates an undefi
fined increased echogenicity of
fatty lobules (arrowheads) refl
flecting hemorrhagic fat infi
filtration. Note that the abnormal area is located just superfi
ficial to the osseous prominence of the greater trochanter (asterisk). b Longitudinal 12–5 MHz US image over the anterolateral thigh in another
patient with previous local contusion caused by a sharp object. US shows three well-circumscribed hypoechoic areas (arrows)
surrounded by ill-defi
fined hyperechoic halo (arrowheads) within the subcutaneous tissue (asterisk) representing fat necrosis
b
27
Skin and Subcutaneous Tissue
*
*
a
T
b
c
Fig. 2.8a–c. Superfi
ficial hematoma: spectrum of 12–5 MHz US appearances. a Hematoma of the subcutaneous tissue examined
a few days after blunt trauma. US demonstrates an echo-free fl
fluid collection (asterisks) reflecting
fl
the phase of clot liquefaction. b Pretibial hematoma (arrowheads) examined 15 days after trauma reveals closely packed fibrous stranding within the
collection refl
flecting fibrin organization. T
T, tibia. c Residual fibrous scar following a large hematoma in the buttock. US shows
the scar as a hyperechoic reflection
fl
(arrows) with posterior acoustic shadowing (open arrowheads) causing distorsion of the
adjacent subcutaneous fat (white arrowheads)
that may mimic a tendon gap at physical examination. US can determine whether the discontinuity
is limited to the subcutaneous fat or involves the
deeper structures too (Thomas et al. 2001) (Fig. 2.10).
Subcutaneous scars are easily depicted with US as
vertically -oriented thin linear stripes surrounded
by hyperechoic halo that interrupt the normal tissue
layers. The abnormal tissue can extend deeply across
the fascia into the muscles or the ligaments. Scars
may eventually calcify (see Fig. 2.8c).
*
2.3.2.5
Foreign Bodies
Foreign bodies can be found in the subcutaneous tissues as the result of traumatic injuries or therapeutic procedures. In a post-traumatic setting, foreign
bodies derive from open or penetrating wounds. Most
are composed of plant fragments (wood splinters,
thorns, etc.), metal or glass. In terms of prevalence,
wood fragments are the most frequently found, fol-
*
a
b
Fig. 2.9a,b. Foreign-body-related abscess. a Longitudinal and b transverse 12–5 MHz US images over the dorsum of the hand in
a patient with signs of local inflammation
fl
and a recent open wound. US demonstrates a subcutaneous collection (asterisk) with
posterior acoustic enhancement (black arrowheads) and fl
fluid-debris levels (open arrowheads). A small highly refl
flective foreign
body (white arrowhead) is contained within the collection. Surgery revealed an abscess containing a small wood splinter
28
M. Valle and M. P. Zamorani
* *
*
*
*
a
b
Fig. 2.10a,b. Subcutaneous fat fracture. a Transverse and b longitudinal 12–5 MHz US images of the gluteal region in a patient
with previous local blunt trauma reveal a wide fl
fluid-fi
filled gap (arrowheads) representing a subcutaneous fat fracture. Note the
disrupted appearance of fatty lobules (asterisks) and the alignment of the fracture plane with the edge (white arrow) of the
iliac bone
a
d
b
c
e
Fig. 2.11a–e. Foreign bodies: US appearance in two patients presenting with a–c wood and d,e glass fragments. a Long-axis and
b short-axis 12–5 MHz US images of a carpenter who injured his left hand during manual work show an elongated hyperechoic
foreign-body (arrow) inside the subcutaneous tissue. The fragment is surrounded by a hypoechoic rim (arrowheads) representing reactive edema and granulation tissue. c At surgery, a wood splinter 1 cm long was removed. d Sagittal 12–5 MHz US image
of the distal forearm with e radiographic correlation in a patient who had an accident during which he broke a glass with his
left hand. Initially, physical exploration was negative for foreign bodies and the wound was sutured. At 3 weeks after trauma, US
demonstrated two bright linear images (arrows) with posterior reverberation (arrowheads) refl
flecting retained glass fragments
in the subcutaneous tissue, just superficial
fi
to the ulnar nerve (arrowheads). e Radiographic correlation
Skin and Subcutaneous Tissue
lowed by glass and metal fragments (Anderson et al.
1982). Part of them may remain at the site and unrecognized even after apparent successful removal by
the patient at the time of the injury (Peterson et
al. 2002). If missed, foreign bodies can results in
granuloma formation, secondary soft-tissue infection with formation of an abscess, fistula, purulent
tenosynovitis and septic arthritis. Bone destructive changes and damage to adjacent nerves may
also occur (Choudhari et al. 2001; Peterson et al.
2002). An early diagnosis and prompt removal of
foreign bodies is required to prevent complications.
Physical examination has intrinsic limitations for
detecting and localizing small foreign bodies due to
the associated local soft-tissue swelling and pain. It
has been reported that approximately 38% of foreign
bodies can be overlooked at the initial clinical investigation (Anderson et al. 1982). The deep position of
a fragment makes palpation more difficult and less
successful. Plain radiography is the initial imaging
modality to identify and localize foreign bodies but
it can only show radio-opaque fragments: even if
very small, metallic fragments are readily detected
on plain films. Detection of glass fragments depends
on their size and, less importantly, on their lead
content, as even if lead-free, almost all glass material is radio-opaque to some degree on radiographs
(Felman and Fisher 1969). Radiolucent fragments,
such as wood splinters, plant thorns and plastic fragments, cannot be detected by X-rays. Although radiographs allow an estimate of the fragment’s location
and its relationships with adjacent bones and joints,
in relation with tendons, vessels and nerves cannot
be investigated. In addition, local complications are
not recognized. Xeroradiography and low-kilovoltage radiography have been proposed to increase the
detection rate of foreign bodies, but these techniques
are currently obsolete.
US is an excellent means of detecting and evaluating post-traumatic foreign bodies (Dean et al.
2003; Soudack et al. 2003; Friedman et al. 2005;
Jacobson 2005). In cases of suspected foreign
bodies, the examiner should extend the study to a
larger area than that closely surrounding the skin
wound, as fragments may migrate far away from the
entrance point as a result of repeated muscle contraction (Choudhari et al. 2001). As an example, it
is not unrealistic to hypothesize that a retained fragment entered the soft tissues on the volar aspect of
the wrist may dislocate proximally to reach the anterior distal forearm. As assessed in cadaveric and in
vivo studies, the US appearance of foreign bodies
varies to a great extent depending on the composi-
tion (metal, glass, wood, etc.), shape and site of the
fragment (Blyme et al. 1990; Horton et al. 2001).
Either radio-opaque or radiolucent fragments can
be identified with US as reflective structures with
posterior acoustic shadowing or reverberation artifact, depending on the surface characteristics and
composition of the foreign body (Boyse et al. 2001;
Horton et al. 2001). In general, wood fragments
are characterized by posterior acoustic shadowing,
whereas glass and metal exhibit reverberations and
comet tail artifact (Fig. 2.11). Although these findings lack specificity, they can help to identify foreign bodies as such. Detection of posterior acoustic
artifact is particularly helpful for locating tiny fragments that, because of their small size, can go unnoticed. Similarly, a hypoechoic halo surrounding the
fragments is of the utmost importance to distinguish
them from adjacent soft-tissue structures, such as
fat strands or muscles. As assessed in a comparative
US-pathologic study, the halo correlates with fibrin,
granulation tissue and collagenous capsule formation, whereas the hypervascular pattern seen at color
Doppler imaging reflects neovasculature (Davae et
al. 2003). The examiner should be aware that US is
not accurate for evaluating the fragment’s size, as the
technique is able only to delineate its surface. On the
other hand, the relationship of foreign bodies with
adjacent vessels, tendons, muscles and nerves can
be precisely assessed. US can recognize a variety of
complications, including abscess, granuloma, infectious tenosynovitis and septic arthritis (Fig. 2.12).
Generally speaking, the main limitations of this
technique occur in the acute phases of trauma, when
open wounds or soft-tissue emphysema may make
the examination difficult. In an acute setting, care
should be taken to avoid contamination of the open
wound with gel. In these circumstances, the use of
sterile gel and a lateral approach to the skin wound
can be recommended to image the fragment. If the
foreign body is retained in the distal arm or in the
distal leg, US examination can be better performed
by placing the affected extremity in a water bath
(Blaivas et al. 2004). As determined in an in vitro
study, air bubbling can decrease the visibility of foreign bodies, leading to attenuation of the US beam
deep to the gas (Lyon et al. 2004). In a preoperative
setting, US can identify the foreign body, place a skin
mark over it and measure the depth of the fragment
relative to the skin. As described in Chapter 18, US
can guide the removal of superficial foreign bodies
during real-time scanning (Shiels et al. 1990).
In summary, when a foreign body is suspected
on clinical grounds, the examiner should briefly
29
30
M. Valle and M. P. Zamorani
*
*
a
*
T
T
*
T
b
T
*
T
c
Fig. 2.12a–c. Tenosynovial foreign body. a Short-axis and b long-axis 15–7 MHz US images over the palm show an elongated
wood fragment (curved arrow) that has penetrated within the synovial sheath of the flexor tendons (T). A thin hypoechoic effusion (asterisks) in the tendon sheath allows the fragment to be precisely located in the synovial space. c Short-axis color Doppler
15–7 MHz US image reveals a hypervascular flow
fl pattern in the flexor tendon sheath as an expression of reactive hyperemia
discuss the context of trauma with the patient to
hear about the nature of possible fragments (glass,
wood, metal, etc.). Radiographs should be always
performed before US examination. Then, US scanning should cover a wide tissue area around the
wound, as foreign bodies may migrate far away
from the penetration site. The examiner should seek
for bright echoes in the soft tissues but, even more,
for structures with posterior acoustic attenuation.
Once detected, the fragment should be measured as
regards its size, orientation, distance from the skin,
and relationships with adjacent tendons, nerves and
vessels. Signs of possible infectious complications,
such as fluid collections and tenosynovitis, should be
annotated as well. Instead of writing a long descriptive report, we prefer to mark the skin overlying the
fragment reproducing its size and orientation and
to measure the depth of the foreign body: these are
important pieces of information for the surgeon
before removal. For foreign bodies in deep locations,
we recommend appending a drawing to the written
report in an effort to better explain the relationship
of the foreign body with the adjacent structures.
Orthopaedic implants (screws, pins, etc.) can be
found in the soft tissues as a consequence of loosening of orthopaedic devices. Metallic devices appear
as bright hyperechoic structures with posterior
reverberation artifact (Fig. 2.13). Although they are
easily detected on plain films, US allows an excellent analysis of the relationship of loosened implants
with adjacent structures, thus helping to plan their
removal (Grechenig et al. 1999). Implantable subcutaneous devices are used as long-acting and effective methods of contraception. They consist of a
single rod implanted in the subcutaneous tissue of
the medial aspect of the arm to release levonorgestrol into the systemic circulation. Based of physical findings, identification of the rod can be difficult if it has inadvertently been inserted too deep
or it has migrated away from the insertion point. If
removal is required, US is an efficient modality to
precisely localize nonpalpable rods, thus allowing
their easy removal (Amman et al. 2003; Piessens et
al. 2005). Rods appear as a small, elongated, hyperechoic structures with well-defined definite posterior
acoustic shadowing, an appearance that correlate
well with in vitro findings (Fig. 2.14) (Amman et al.
2003). MR imaging should be used only if US is unrewarding (Merki-Feld et al. 2001). Tissue expanders
are widely used in plastic and reconstructive surgery
(Neumann 1957). US can assess twisting of injection
ports that are surgically inserted into the subcutaneous tissue (Kohler et al. 2005). Twisting is associated with failure of the injection procedure and
fluid accumulation in the subcutaneous tissue. US
easily demonstrates the upside-down position of the
port by showing the linear hyperechoic appearance
of the metallic base tilted toward the skin replacing
the normal concave superior face of the soft silicone
component (Kohler et al. 2005). Suture granulomas
may occur after a surgical intervention in which
nonabsorbable stitches are used. These tumor-like
lesions usually develop slowly and may cause only
vague symptoms or remain asymptomatic for many
years. US is an accurate way to identify and characterize them by depicting suture material within
(Fig. 2.15). As assessed in an in vitro study, the US
appearance of surgical sutures is independent of
their chemical composition. Monofilament sutures
appear as straight bright double lines (like railway
31
Skin and Subcutaneous Tissue
a
b
Cor
c
Fig. 2.13a–c. Loosened surgical screw. a Anteroposterior radiograph of the shoulder with correlative b transverse and c splitscreen sagittal 12–5 MHz US images over the pectoralis region in a patient with a loosened screw (curved arrow) following previous surgery on the shoulder. a Radiograph reveals the loosened screw projecting over the right chest but it does not indicate its
precise location. b At US examination, the screw (curved arrow) appears as a hyperechoic structure with posterior reverberation
artifact (straight arrows) presenting a head (white arrowhead) and multiple hyperechoic teeth (open arrowheads) at its anterior
aspect corresponding to screw spirals. In c, the screw appears as a small hyperechoic dot (curved arrow) surrounded by fluid
collection (arrowhead) due to local inflammatory
fl
reaction. US allows accurate assessment of the relationship of the screw with
the short head of the biceps and the coracobrachialis muscles (open arrows) arising from the coracoid (Cor)
lines) due to high-amplitude reflection of the US
beam at the superficial and deep interface of the
suture with the surrounding tissue; braided sutures
most often produce a single echo (Rettenbacher et
al. 2001). Both patterns show posterior reverberation
artifacts. In general, the surrounding granuloma
appears as an ill-defined hypoechoic mass, containing a liquefied center where the stitch lies. The main
differential diagnoses are granulomas containing
other foreign bodies and inflamed epidermoid cysts
containing a hair.
2.3.3
Tumors and Tumor-Like Conditions
Soft tissue masses of the subcutaneous tissue include
a variety of lesions, such as calcifications, tophaceous gout or rheumatoid nodules, sebaceous cysts
and tumors, ranging from the common lipomas and
hemangiomas to the rare metastasis and primary
malignant masses. Scattered calcifications in the
subcutaneous tissue are observed in scleroderma
and systemic lupus erythematosus. They appear as
mottled hyperechoic lesions with posterior acoustic
shadowing. US has little value in their assessment
as they are manifest on plain films. Subcutaneous
calcifications are often the result of drug injections.
For the most part, they are encountered in the buttock and appear as well-delimited hyperechoic
structures with strong posterior acoustic shadowing
(Fig. 2.16a). In rheumatologic patients, subcutaneous nodules are mainly due to tophaceous gout or
rheumatoid nodules (Tiliakos et al. 1982; Benson
et al. 1983; Nalbant et al. 2003). Tophi are softtissue agglomerates of uric acid crystals that can
develop in different areas of the body: the hand, the
foot and the elbow the most commonly involved.
32
M. Valle and M. P. Zamorani
a
b
c
Fig. 2.14a–c. Subdermal contraceptive device (Implanon). a Short-axis and b long-axis 12–5 MHz US images over a flexible
fl
subdermal plastic implant (arrows) for long-acting release of synthetic hormones. In selected cases, US can assist in the localization
and minimally invasive removal of the implant. c Photograph of an Implanon rod after surgical removal
a
b
Fig. 2.15a,b. Suture granuloma. a Long-axis and b short-axis 12–5 MHz US images show a suture granuloma located in the
lower abdominal wall after inguinal herniorrhaphy. Within the hypoechoic granuloma (arrows), the surgical suture appears
as a hyperechoic rail-like line (arrowheads) when imaged in its long-axis. On the short-axis image, the suture assumes the appearance of a double dot (arrowhead)
At US examination, tophi appear as heterogeneous masses containing hypoechoic areas related to
chalky liquid material surrounded by hyperechoic
tissue (Nalbant et al. 2003). Rarely, calcific deposits can be detected within the tophaceous mass in
the form of hyperechoic spots with or without posterior acoustic attenuation (Fig. 2.16b) (Gerster et
al. 2002). Rheumatoid nodules occur in 20–30% of
rheumatoid patients who have a high serum level
of rheumatoid factor and active articular disease
(McGrath and Fleisher, 1989). They seem to
derive from an immune complex process between
rheumatoid factor and immunoglobulin G initiating small vessel abnormalities and then progressing
to necrosis and granulation tissue. Gross examination of these nodules reveals a semifluid center sur-
33
Skin and Subcutaneous Tissue
*
*
a
b
A
*
A
*
A
c
d
Fig. 2.16a–d. Non-neoplastic subcutaneous masses. a Elaioma. Transverse 12–5 MHz US image demonstrates dystrophic calcification (arrows) in the subcutaneous tissue of the buttock, at the site of previous injection therapy. b Tophaceous gout. Longitudinal 12–5 MHz US image over the forefoot reveals tophi as para-articular ill-defi
fined hypoechoic masses (asterisks) with
posterior acoustic shadowing (open arrowheads) and hyperechoic surrounding halo (arrows), adjacent to the MIP joint. Note
the osteoarthritic changes (white arrowheads) in the underlying joint. c,d Rheumatoid nodules. c Transverse and d longitudinal
12-5 MHz US images over the Achilles tendon (A) in an HIV-positive patient affected by longstanding rheumatoid arthritis show
a rheumatoid nodule as a hypoechoic mass (arrows) arising from the paratenon and growing into the subcutaneous tissue. The
nodule has a mixed echotexture with solid (asterisk) and fl
fluid (arrowheads) components
rounded by dense connective tissue. Rheumatoid
nodules are usually found at pressure sites, such as
the extensor aspect of the elbow, the fingers and the
calcaneus, and correlate with a bad prognosis. US
displays hypoechoic masses with a central sharply
demarcated hypoechoic area reflecting necrosis
(Fig. 2.16c,d) (Nalbant et al. 2003).
2.3.3.1
Lipomas
Superficial lipomas typically appear as compressible, palpable soft-tissue masses in the subcutaneous
tissue not adherent with the overlying skin. Lipomas have a male and familial predominance and
tend to grow in the back, shoulder and upper arms
with a predilection for the extensor surface. They
are more common in the fifth and sixth decades.
Although lipomas most often present as a solitary
oval or rounded mass, they may be multiple (5%–
15%) (Murphey et al. 2004). At US examination,
lipomas have a wide range of appearances. Typically, they present as elliptical compressible masses
containing short linear reflective striations that run
parallel to the skin (Fig. 2.17a). However, their internal echogenicity may vary from hyperechoic to hypoechoic or mixed relative to muscle depending on
the degree of connective tissue and other reflective
interfaces – such as cellularity, fat and water – within
the mass (Fornage and Tassin 1991; Ahuja et al.
1998). At least theoretically, it has been postulated
that lipomas composed of pure fat should be echofree lesions due to a low number of tissue acoustic
interfaces (Behan and Kazam 1978). Based on different series, the incidence of hyperechoic lipomas,
reflecting the so-called fibrolipomas, varies from
20% to 76% (Fornage and Tassin 1991; Ahuja et
al. 1998; Inampudi et al. 2004). In a recent retrospective review of 39 US-diagnosed superficial and
34
M. Valle and M. P. Zamorani
c
b
a
*
Muscle
d
e
Fig. 2.17a–e. Subcutaneous lipoma: spectrum of typical US appearances. a Long-axis extended-fi
field-of-view 12–5 MHz US
image of a lipoma of the back shows an elongated well-defi
fined compressible mass with its greatest diameter parallel to the
skin. The mass has well-defi
fined margins and appears slightly hyperechoic relative to adjacent fat. Its echotexture consists of
short thin linear striations that run parallel to the skin. b Long-axis 12–5 MHz US image at the border of a nonencapsulated
lipoma (arrows) in a patient with a palpable mass at the medial aspect of the left thigh with c correlative contralateral image.
d Long-axis 12–5 MHz US image of an intrafascial lipoma shows a lenticular fatty mass (asterisk) contained in a split of the
muscle fascia (arrows). Note the fascia dividing into two hyperechoic sheets (arrowheads) to envelop the lipoma. e Transverse
12–5 MHz US image of the left forearm in patient with pathologically-proven angiolipoma demonstrates a hyperechoic rounded
mass (arrows) with small internal hypoechoic dots
25 lipomas and 14 nonlipomas, including other
benign and malignant histotypes (Inampudi et al.
2004). This indicates that the variable echotexture
of lipomas may make their differentiation from
other masses subjectively difficult. Although many
lipomas have a well-circumscribed appearance with
an identifiable thin capsule, a significant proportion (12%–60%) have ill-defined borders blending
imperceptibly with the surrounding subcutaneous
fat (Fig. 2.17b,c) (Fornage and Tassin 1991; Ahuja
et al. 1998; Inampudi et al. 2004). This may lead to
difficulties in identifying them with US even if the
mass is apparent clinically. Nonencapsulated lipomas may require comparison with the contralateral
side to detect significant asymmetry of fat tissue.
They should be referred to as “probable lipomas” in
the report as long as there are corroborative clinical
findings of a discrete mass (Roberts et al. 2003).
In daily practice, the occurrence of a superficial
palpable lump suggesting a lipoma in the absence of
a definite nodule detectable with US is not uncommon. Graded compression with the probe or combined imaging and palpation may be helpful for
detecting these “occult” lipomas. Both maneuvers
can increase the detection rate of the mass, which
is less compressible than the adjacent subcutaneous tissue. Most superficial lipomas do not present
substantial internal vasculature at color and power
Doppler imaging, a finding that may enhance the
confidence of the examiner that a benign mass is
present (Ahuja et al. 1998). Some lipomas grow in
the deep subcutaneous tissue, in close contact with
the fascia. Care should be taken when reporting
on these masses not to lead the surgeon to believe
that the lesion can be easily excised, because deep
subcutaneous lipomas may adhere to the fascia. A
well-delimited mass does not always mean an easily
Skin and Subcutaneous Tissue
removable lesion. Lipomas growing inside the deep
fascia may also occur. The clinical diagnosis of these
lesions may be difficult because they are firm and
tethered to the deep plane and may mimic more
aggressive tumors. At US examination, intrafascial
lipomas appear as lenticular lesions growing into
a split of the fascia, which retains a normal hyperechoic appearance (Fig. 2.17d). In these cases, US
can rule out abnormalities of the underlying muscles and aggressive growth patterns suggestive of a
malignant tumor.
Lipomas containing other mesenchymal elements, such as fibrous tissue (fibrous lipomas),
cartilage (chondroid lipomas), mucoid component
(myxolipoma) and vessels (angiolipoma), may be
encountered. In these cases, the presence of nonlipomatous elements may make the US appearance
of the lesion less specific. Among these variants,
angiolipomas account for 5%–17% of all lipomas
(Lin and Lin 1974). They are well-defined hyperechoic subcutaneous masses containing small
patchy hypoechoic areas and sparse internal vasculature (Fig. 2.17e) (Choong 2004). Relative to
lipomas, angiolipomas have a greater angiomatous
component composed of thin-walled capillaries
which account for up to 90% or more of the lesion,
and occur at an earlier age (early adulthood).
Hibernomas (fetal lipomas) are rare benign tumors
composed of brown fat. Brown fat is histologically
distinct from white adipose tissue and plays a role
in nonshivering thermogenesis of hibernating animals and newborn humans. In humans, brown
adipose tissue progressively decreases through
adulthood. Usual locations of tumors arising from
brown fat are the parascapular and interscapular
spaces, the mediastinum, the upper thorax and
the thighs. US demonstrates a solid well-marginated hyperechoic mass somewhat resembling a
lipomatous tumor and Doppler imaging may show
a hypervascular pattern reflecting the presence
of vascular structures and the increased cellular metabolism of hibernomas. Other rare forms
of lipomas, including lipomatosis of nerves (see
Chap. 4) and lipoma arborescens (see Chap. 14) are
described elsewhere.
Other space-occupying nonlipomatous masses
containing fat may mimic the US appearance of lipomas. Among them, hemangiomas contain a variable amount of adipose tissue interspersed between
abnormal vessels. However, in most cases their typical US appearance made of serpentine or tubular
hypoechoic structures contained within the mass,
scattered phleboliths and prominent blood flow at
color and power Doppler imaging, allows the correct
diagnosis to be made.
Lipomatosis represents a diffuse overgrowth
of mature adipose tissue histologically similar to
simple lipomas. The fatty tissue extensively infiltrates the subcutaneous and muscular tissue and
is not associated with nerve involvement. Many
entities of superficial lipomatosis are described
(Murphey et al. 2004). In multiple symmetric
lipomatosis, which is commonly referred to as
Madelung or Launois-Bensaude lipomatosis, multiple symmetric lipomas are found in the neck
and the shoulder in association with alcoholism,
hepatic disease and metabolic disorders (Uglesic
et al. 2004). Dercum disease, which is also referred
to as lipomatosis dolorosa or adiposis dolorosa, is
a rare disorder occurring in middle-aged women,
often obese, in which multiple painful subcutaneous lipomas occur (Wortham and Tomlinson
2005).
2.3.3.2
Pilomatricoma and Epidermal Inclusion
(Sebaceous) Cysts
Pilomatricoma (pilomatrixoma), also called calcifying epithelioma of Malherbe, is a benign superficial tumor of the hair follicle arising from the hair
cortex cells in the deep dermis and extending into
subcutaneous tissue as it grows (Malherbe and
Chemantais, 1880). Most lesions arise in children
less of 10 years of age and appear as small masses
(<3 cm in diameter) with a rock-hard consistency
and an irregular surface, which causes skin stretching over the mass (Hwang et al. 2005). Although the
overall incidence of pilomatricoma is low, it is one
of the most commonly excised superficial masses
in children with epidermoid cysts. Preferential
anatomic sites of pilomatricomas are the neck, the
cheek, the preauricular area and the extremities,
including arm and leg. US demonstrates pilomatricomas as hyperechoic masses relative to the muscle
with posterior acoustic shadowing reflecting internal calcification or ossification (Fig. 2.18a) (Hwang
et al. 2005). The amount and shape of calcification
may vary from few scattered echogenic foci to gross
clumped deposits within the mass or a completely
calcified nodule. In most cases, a peripheral hypoechoic rim surrounding the calcific deposits is
observed (Hwang et al. 2005). Peripheral color Doppler flow is often found in the peripheral region of
the mass.
35
36
M. Valle and M. P. Zamorani
a
b
Fig. 2.18a,b. Epidermal-related masses. a Pilomatricoma. Transverse 10–5 MHz US image in a child with a stiff superficial
fi
lump
in the preauricular area reveals a mass (arrows) characterized by a peripheral hypoechoic rim and a hyperechoic center with
fi foci causing posterior acoustic attenuation. b Epidermal inclusion cyst. US demonstrates a rounded hypoescattered calcified
fi
extension into the dermis
choic mass (arrow) with posterior acoustic enhancement (white arrowheads) and a small superficial
(open arrowhead)
Epidermal inclusion cysts, which are also referred
to as sebaceous, epidermoid, epidermal, infundibular or keratin cysts, derive from the focal proliferation of epidermal cells within the subcutaneous
tissue. The theory that these cysts may develop from
the subcutaneous implantation of keratinizing epithelial elements during embryogenesis or a previous
trauma or surgery is widely accepted. Sebaceous cysts
most often arise from swollen sebaceous glands or
hair follicles and are limited to the skin surfaces in
which sebaceous glands are present (i.e., the dorsal
but not the ventral aspect of the hand). Epidermal
inclusion cysts are lined with epithelial cells and
filled with a white, cheesy material reflecting layers
of keratin and cholesterol-rich debris. Clinically,
epidermal inclusion cysts present as slow-growing, freely movable lumps beneath the skin. They
usually remain asymptomatic unless they become
infected, grow large enough to interfere with normal
function, or rupture into the adjacent soft tissues.
US shows epidermal cysts as ovoid or spherical
sharply bordered hypoechoic masses with scattered
echoes presenting posterior acoustic enhancement
and a small extension into the dermis corresponding to their small opening that communicates with
the skin (Fig. 2.18b) (Lee et al. 2001). However, the
internal echogenicity of epidermoid inclusion cysts
may vary depending on the hydration of the keratin, protein composition and microcalcifications
(Fig. 2.19) (Vincent et al. 1985; Lee et al. 2001).
The typical “onion-ring” (bull’s-eye) appearance
described in the testis as a result of multiple layers
of keratin debris is usually not observed in epider-
mal cysts arising from soft tissues (Brenner et al.
1989; Maxwell and Mamtora 1990). Ruptured
cysts may assume a lobulated or irregular contour
as a result of intense granulomatous reaction and
show color Doppler signals, possibly mimicking a
neoplasm (Lee et al. 2001).
2.3.3.3
Hemangiomas and Vascular
Malformations
Even though the term “hemangioma” is often used
in a general way to encompass both hemangiomas
and vascular malformations, hemangiomas represent endothelial-lined neoplasms that mainly occur
in childhood, growing to reach a maximum volume
and then regress, whereas vascular malformations
are composed of dysplastic vessels which show no cellular proliferation or regression. Hemangiomas can
be categorized into capillary and cavernous types,
whereas vascular malformations may be divided in
high-flow, slow-flow and capillary lesions. Hemangiomas may be hypoechoic or hyperechoic relative
to surrounding tissue and may have a homogeneous
or complex appearance (Fig. 2.20a). High vessel density and high peak arterial Doppler shifts (>2 kHz)
are typically observed and help in distinguishing hemangiomas from other soft-tissue masses
(Fig. 2.20b–f) (Dubois et al. 1998, 2002). High-flow
malformations are typified by an abnormal network
of vascular channels (the nidus), interposed between
a prominent feeding artery and a dilated draining
Skin and Subcutaneous Tissue
T
b
a
c
d
Fig. 2.19a–d. Epidermal inclusion
cyst. a Lateral radiograph of the
middle finger in a patient with a
palpable mass on the ventral aspect
of the proximal phalanx reveals a
superfi
ficcial oval soft-tissue mass
(arrows). b Transverse 12–5 MHz
color Doppler US image of the affected finger demonstrates a wellcircumscribed hypovascular mass
(arrows) characterized by a homogeneous texture of medium-level
echoes in close relationship with
the flexor tendons (T). Correlative c fat-suppressed T2-weighted
and d gadolinium-enhanced fatsuppressed T1-weighted MR images show a homogeneous lesion
(arrow) of high signal intensity
on T2-weighted images, central
non-enhancement and peripheral
thin rim enhancement. Surgery revealed an epidermal inclusion cyst
d
T
T
a
b
e
c
f
Fig. 2.20a–f. Hemangioma. Transverse a gray-scale and b color Doppler 15–7 MHz US images of the index finger
fi
in a patient
with an indolent palpable mass demonstrate a well-circumscribed solid hypoechoic nodule (arrows) located just superficial
fi
to the fl
flexor tendons (T). The mass reveals several intratumoral vessels. c Coronal fat-suppressed T2-weighted and transverse
d T1-weighted, e fat-suppressed T2-weighted and f gadolinium-enhanced T1-weighted MR imaging correlation
37
38
M. Valle and M. P. Zamorani
vein. Spectral Doppler analysis demonstrates high
systolic arterial flow and arterialization of the veins
(Fig. 2.21) (Dubois et al. 1999). Slow-flow (venous)
malformations are characterized by abnormally
dilated venous spaces and a normal arterial component. Often, they may be suspected on the basis of
a subcutaneous bluish or reddish stain. In approximately 15% of cases they contain phleboliths (calcifications in venous thrombosis), which can be seen
as hyperechoic foci with posterior acoustic shadowing (Fig. 2.22). Due to slow blood flow, color Doppler
imaging may detect only sparse monophasic flow or
no blood flow signals at all (Trop et al. 1999). Distinguishing between a slow-flow malformation and
an involuted hemangioma may be problematic. In
general, vascular malformations are distinguished
from hemangiomas owing to the absence of solid
tissue (Paltiel et al. 2000). In addition, hemangiomas have similar vessel density and peak systolic
velocities but lower venous velocity (Paltiel et al.
2000). Finally, there are capillary malformations
limited to the dermis. For the most part, US is unable
to display such superficial abnormalities that typically present with a port-wine like stain. In some
instances, however, an increased thickness of the
subcutaneous tissue and some prominent veins may
be demonstrated.
2.3.3.4
Metastases and Lymphomas
Superficial metastases involving the skin and subcutaneous tissue account for approximately 0.5%–9%
of tumors. They usually result from seeding of deep
tumors during interventional (i.e., needle and surgical biopsy) or surgical procedures or represent a
manifestation of end-stage cancer (Galarza and
Sosa 2003). In some cases, however, skin metastases
can be the first manifestation of an occult cancer,
therefore requiring an accurate and early diagnosis (Giovagnorio et al. 2003). Histopathologically,
metastases of the skin and subcutaneous tissue can
develop from almost any kind of malignancy, but
nearly half of them derive from melanoma, lung
cancer and breast carcinoma (White 1985). In most
cases, metastases appear as well-circumscribed
solid hypoechoic masses (Nazarian et al. 1998).
A lobulated shape and multiple peripheral vascular
pedicles feeding internal irregular vessels seem the
most important gray-scale and color Doppler US
imaging findings for differentiating them from other
benign soft-tissue masses (Fig. 2.23) (Giovagnorio
et al. 1999, 2003). In follow-up studies, color Doppler imaging has been proposed as a mean to assess
the pharmacodynamic response to chemotherapy
a
b
c
Fig. 2.21a–c. Arteriovenous malformation. a Transverse gray-scale 15–7-MHz US image of a 6-month-old infant born with a
markedly swollen cheek and upper lip reveals marked thickening of the subcutaneous tissue of the lip (arrows). b Corresponding color Doppler 15–7 MHz US image demonstrates numerous enlarged vessels coursing through the thickened subcutaneous
tissue. c Spectral Doppler analysis demonstrates high-velocity arterial waveforms within the vessels
39
Skin and Subcutaneous Tissue
a
c
b
Fig. 2.22a–c. Venous malformation. a Longitudinal 12–5 MHz US image of the middle forearm show an ill-defined
fi
sponge-like
subcutaneous mass (arrowheads) containing a network of anechoic channels and a hyperechoic dot (arrow) with posterior
acoustic shadowing, likely reflecting
fl
a phlebolith. b Corresponding 12–5 MHz color Doppler US image reveals only a few, weak
signals of flow within the soft-tissue mass (arrowheads). c Radiographic correlation confi
firms the presence of a few rounded
phleboliths (arrow) within the lesion
*
a
c
*
b
Fig. 2.23a–c. Subcutaneous tissue metastases. a,b Gray-scale and c,d color Doppler 12–5 MHz US images in two patients with
previously diagnosed malignancies demonstrate well-defi
fined homogeneous hypoechoic nodules (asterisk) located within the
subcutaneous tissue. In both nodules, correlative color Doppler imaging shows a hypervascular pattern with peripheral and
internal vessels. Postsurgical histologic examination revealed metastases from a,c gut carcinoma and b,d colon adenocarcinoma
d
40
M. Valle and M. P. Zamorani
by depicting reduction of intratumoral blood flow
(Fig. 2.24) (Nazarian et al. 1996). In patients operated on for melanoma, detection of any nonpalpable
mass in the subcutaneous tissue or any suspected
regional lymphadenopathy should be ascertained by
means of US-guided biopsy (Fornage and Lorigan
1989).
The subcutaneous tissue can be the primary site of
involvement of peripheral T-cell (non-Hodgkin) lymphoma (Lee et al. 2003; Fujii et al. 2004; Giovagnorio
1997). This kind of lymphoma involves the skin and
the subcutaneous tissue in two main forms: the
cutaneous T-cell lymphoma, which is also known as
mycosis fungoides or Sézary syndrome, and the subcutaneous panniculitis-like T-cell lymphoma (Lee et
a
b
al. 2003). Mycosis fungoides is an indolent disorder
presenting with cutaneous patches, plaques or erythroderma. With time, the skin lesions may progress
to cutaneous tumors, peripheral lymphadenopathies
and widespread extracutaneous involvement, with a
corresponding drop in patient survival rate. At the
stage of tumor formation, US is able to demonstrate
diffuse or focal hypoechoic thickening of the skin;
the imaging features of this lymphoma are, however,
nonspecific (see Fig. 2.3a) (Fornage et al. 1993). The
subcutaneous panniculitis-like T-cell lymphoma is a
rare condition which may be a diagnostic challenge
as it mimics inflammatory cellulitis associated with
connective tissue disease (Lee et al. 2003; Sy et al.
2005). This disorder usually presents with multiple
c
Fig. 2.24a–c. Subcutaneous regional metastasis from melanoma. a Gray-scale and b,c color Doppler 15–7 MHz US images in a
patient who had a melanoma in his left foot and some regional relapses reveal a small solid homogeneously hypoechoic nodule
(arrow) with spiculated margins in the subcutaneous tissue of the left lower leg. The nodule is hypervascular at color Doppler
imaging. c After a course of systemic chemotherapy and immunotherapy, the subcutaneous metastasis appears unchanged in
size and echotexture but assumes a hypovascular pattern reflecting
fl
therapy-related change in tumor perfusion
a
b
Fig. 2.25a,b. Subcutaneous panniculitis-like T-cell lymphoma. a Gray-scale and b color Doppler 12–5 MHz US images over an
hardened ill-defi
fined area in the back show diffuse pseudonodular thickening of the subcutaneous tissue (arrows) with a generalized decrease in echogenicity of the fat lobules and a diffuse hypervascular pattern mimicking cellulitis
Skin and Subcutaneous Tissue
palpable subcutaneous nodules, and may undergo
rapid deterioration secondary to the onset of the
hemophagocytic syndrome (marked anemia due to
phagocytosis of red blood cells from monocytes and
macrophages). US reveals marked increased echogenicity with swelling of the fat lobules and blurry
differentiation between the skin and the subcutaneous tissue, an appearance resembling a diffuse
inflammatory infiltrate with edema (Fig. 2.25) (Sy
et al. 2005). Hypoechoic nodules surrounded by a
hyperechoic rim can also be observed (Fujii et al.
2004). Given the similarity with inflammatory cellulitis, regional enlarged lymph nodes could possibly be misinterpreted as reactive in nature (Sy et al.
2005).
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43
Muscle and Tendon
3
Muscle and Tendon
Maria Pia Zamorani and Maura Valle
CONTENTS
3.1
3.1.1
3.1.2
3.1.3
3.1.3.1
3.1.3.2
3.1.4
3.1.4.1
3.1.4.2
3.1.4.3
3.1.5
3.1.5.1
3.1.5.2
3.1.5.3
3.1.6
3.1.6.1
3.1.6.2
3.1.6.3
3.1.6.4
3.1.6.5
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.4.1
3.2.4.2
3.2.5
3.2.5.1
3.2.5.2
3.2.5.3
3.2.6
3.2.6.1
3.2.6.2
Muscle 45
Histologic Considerations 45
Normal US Anatomy and
Scanning Technique 46
Anatomical Variants and
Heritable Disorders 50
Muscle Agenesis, Anomalous and
Accessory Muscles 50
Neuromuscular Disorders 52
Traumatic Lesions 54
Myotendinous Strains 55
Contusion and Laceration 56
Myositis Ossificans 57
Inflammatory and Ischemic Conditions 59
Idiopathic Inflammatory Myopathies 59
Pyomyositis, Abscess, and
Hydatid Disease 61
Diabetic Muscle Infarction and
Rhabdomyolysis 62
Tumors 64
Intramuscular Hemangioma 64
Deep-Seated Lipoma and Liposarcoma 66
Intramuscular Myxoma 67
Desmoid 69
Rhabdomyosarcoma and Metastases 71
Tendon 71
Histologic Considerations 71
Normal US Anatomy and
Scanning Technique 72
Tendon Instability 75
Degenerative Changes and Tendon Tears
Tendinosis and Partial Tears 76
Complete Tears and Postoperative Findings
Inflammatory Conditions 83
Paratendinitis and Attrition Bursitis 84
Tenosynovitis 85
Enthesopathy 87
Tumors and Tumor-Like Conditions 88
Intratendinous and Tendon Sheath Ganglia
Giant Cell Tumor of the Tendon Sheath
References
45
76
79
88
89
91
M. P. Zamorani, MD
Unité de Recherche et Dévelopement, Clinique des Grangettes,
7, ch. des Grangettes, 1224 Genève, Switzerland
M. Valle, MD
Staff Radiologist, Reparto di Radiologia, Istituto Scientifico
“Giannina Gaslini”, Largo Gaslini 5, 16148 Genova, Italy
3.1
Muscle
3.1.1
Histologic Considerations
On the whole, skeletal muscles can be regarded as
the largest organ of the human body, accounting
for approximately 25–35% of the total body weight
in women and 40–50% in men (Hollman and
Hettiger 1990). They are made up of two components: the muscle fibers, which are long and cylindrical in structure, representing the cellular unit of
muscle, and stromal connective tissue. Individual
muscle fibers are grouped together in bundles,
which are commonly known as fascicles, and several fascicles join together to form an individual
muscle (Fig. 3.1a). Thin connective tissue strands
– the endomysium – separate the individual muscle
fibers; a more substantial connective sheath with
small vessels and nerve endings, the perimysium
(also referred to as fibroadipose septa), envelops
individual fascicles; a thick fibrous layer, the epimysium, surrounds the entire muscle (Fig. 3.1a). Muscle
fibers vary in length and cross-sectional diameter
depending on the individual muscle. Fascicles may
be either coarse, as in the case of large muscles, or
very fine, as in the case of small muscles that coordinate precise movement (Erickson 1997). They insert
into the different connective tissue components of
the muscle, including the peripheral epimysium and
central major septa formed by converging fibroadipose septa. At their distal end, intramuscular septa
join into large tendinous layers – commonly referred
to as aponeuroses – or directly to tendons.
The internal arrangement of the muscle varies
according on the fascicular orientation, which
reflects gross muscle shape and function. A parallel arrangement is found in strap-like (e.g., sartorius) and quadrilateral (e.g., thyrohyoid) muscles,
in which fibers course nearly the full length of the
long axis of the muscle; the rectus abdominis shows
49
Muscle and Tendon
T
a
b
Fig. 3.4a,b. Intramuscular aponeuroses. a Long-axis and b short-axis 12–5 MHz US images of the normal tibialis anterior muscle
(arrowheads) demonstrate the feather-like arrangement of a circumpennate muscle created by the convergence of the fibroadipose septa upon the internal aponeurosis. The aponeurosis (straight arrows) appears as a highly reflective linear echo within
the muscle that is thicker than the fibroadipose septa (curved arrow). T, tibia
a
b
Fig. 3.5a,b. Muscle anisotropy. Short-axis 17–5 MHz US images of the biceps brachii muscle (arrows) examined with a perpendicular angle between the transducer face and the orientation of the muscle fibers and b an angle that deviates slightly from the
perpendicular. In a, the muscle appears diffusely hyperechoic owing to the highest specular reflectivity from the perimysium
interfaces. In b, the overall muscle becomes more hypoechoic with decreased intensity of echoes from the perimysium. On
the other hand, the larger fibroadipose septa (arrowhead) are more visible. Tilting the probe over the muscle may be useful to
distinguish artifactual hypoechoic patterns from mild strains
fibroadipose septa, US is able to recognize the internal architecture of pennate muscles as semipennate,
unipennate, bipennate, or multipennate (Fig. 3.6).
Intramuscular vessels coursing within the hyperechoic septa are visible on color and power Doppler imaging. The outer muscle fascia (epimysium)
appears as a well-delineated echogenic envelope circumscribing the hypoechoic muscle. Large hyperechoic septa (aponeuroses) directed within the muscle
belly can be seen arising from it. In complex muscles,
an individual hyperechoic fascial sheath surrounds
each muscle belly thus helping the examiner to recognize the different heads. The interstice between
juxtaposed fasciae of two adjacent muscles appears
as a hypoechoic band and corresponds to loose connective tissue that allows some sliding of the muscles
during contraction. Focal interruptions of the muscle
fascia are found at the points where nerves, veins,
and arteries (perforating vessels) enter the muscles.
When the muscle fascia lies under the subcutaneous
tissue, it adheres to the superficial fascia and cannot
be distinguished from it.
Dynamic US scanning performed during muscle
contraction can show changes in size and relationship of fascicles and fibroadipose septa. On short-axis
planes, contracted muscles usually appear thicker and
more hypoechoic. Intramuscular septa change their
appearance and orientation as a result of the action of
50
M. P. Zamorani and M. Valle
a
b
Fig. 3.6a,b. Internal architecture of skeletal muscles. a Fusiform muscle. Long-axis 12–5 MHz US image over the deltoid muscle
(arrows) demonstrates the fibroadipose septa (arrowheads) as hyperechoic lines separating the hypoechoic muscle bundles.
These septa have a parallel arrangement along the muscle belly. b Pennate muscle. Long-axis 125 MHz US image over the tibialis
anterior muscle (arrows) demonstrates the fibroadipose septa (arrowheads) as they converge on the highly reflective aponeurosis (curved arrow), giving the appearance of a feather
the muscle fibers that attach into these structures. In
the medial head of gastrocnemius, for instance, pennation angle increases from 15.5° to 33.6° when examined during isometric contraction (Fig. 3.7) (Narici
et al. 1996). Shortening of muscles is well appreciated
on long-axis images during concentric contraction.
Recently, a method to measure muscle tissue perfusion by means of contrast-enhanced power Doppler US has been developed with quantification of
intramuscular blood flow performed at rest and after
exercise (Krix et al. 2005).
3.1.3
Anatomical Variants and Heritable Disorders
3.1.3.1
Muscle Agenesis, Anomalous and Accessory
Muscles
Muscle agenesis indicates the absence of one muscle
or one head of a complex muscle as a result of incomplete or imperfect development. In general, the diagnosis is already evident at physical examination. US
α
A
a
β
A
b
Fig. 3.7a,b. Pennation angle. Long-axis 12–5 MHz US images of the medial head of gastrocnemius obtained a at
rest and b during isometric contraction demonstrate an
increased pennation angle during muscle activation. The
pennation angle is given by the incidence of the muscle
fibers (dashed line) relative to the aponeurosis (A), which
represents the direction of force generation (double arrow).
Note that this angle is greater during contraction (β) than
at rest (α)
Muscle and Tendon
causes profound US changes in muscle architecture
with increased echogenicity, loss of heterogeneity,
and shadowing (Fig. 3.10). The increased echogenicity of muscle reflects an increased number of acoustic interfaces related to fat accumulation, fibrosis,
and inflammation. In neuromuscular disorders, the
increased reflectivity of muscles is associated with a
decreased ability of the US beam to penetrate deeper
structures, leading to loss of bone edge definition
and bone shadowing (Fischer et al. 1998; Walker
et al. 2004). In addition, the disease process blurs the
distinction between fibroadipose septa and muscle
fascicles, making the image more homogeneously
echogenic (Fig. 3.10a).
Similarly, peripheral neuropathies are often
associated with selective atrophy of the innervated
muscles. US is able to evaluate the size and echotexture of the affected muscles by comparing the two
extremities (Scholten et al. 2003). A definite loss in
bulk of the affected muscle would suggest atrophy.
This can be appreciated by simple pattern recognition analysis (concave or straight muscle boundaries instead of the normal convex surface). Because
side-to-side differences in muscle thickness rarely
exceed 20%, measuring the muscle diameters or
cross-sectional area with the electronic calipers of
the equipment seems to be a more reliable means
to assess volume changes in a given group of muscles than subjective evaluation (Bargfrede et al.
1999). The ratio of muscle thickness to subcutaneous fat thickness was found to be helpful in specific neuromuscular disorders (decreased ratio in
spinal muscle atrophy). In neuromuscular disorders, however, US has shown some limitations compared with MR imaging. The complex distribution
of muscle involvement in some dystrophies seems
more reliably mapped with MR imaging because of
its better anatomic rendering and panoramic view.
Based on echotextural pattern analysis, US is not
as accurate as MR imaging in distinguishing early
neurogenic atrophy (in which changes are mainly
related to extracellular edema) from late atrophy
(in which muscle tissue is gradually replaced by fat).
Unlike MR imaging, in which early denervation is
appreciated by a homogeneous hyperintense pattern on T2-weighted and STIR sequences (increase
in free-water content) and late denervation by a
hyperintense pattern on T1-weighted images (fatty
replacement), at US the two processes have a similar
hyperechoic pattern and can be hardly differentiated (Fig. 3.11) (Kullmer et al. 1998). Quantification of muscle echotexture to estimate the severity
of atrophy would reduce the observer variability
but is strongly influenced by the scanner and the
MHG
T
soleus
F
∗
a
∗
b
c
Fig. 3.10a–c. Neuromuscular disorders. a,b Transverse 12-5 MHz US images obtained over the a posteromedial and b posterolateral aspect of the middle third of the leg in a 12-year-old child with Duchenne dystrophy. The affected medial head of the
gastrocnemius (MHG) and soleus exhibits a diffusely hyperechoic pattern with strong US beam attenuation (asterisks) and
blurred distinction of fibroadipose septa. The acoustic shadowing leads to inability of the US beam to penetrate deep structures. In b, there is loss of bone edge definition of the fibula (F) caused by the abnormal muscle reflectivity (arrows). T, tibia. c
Photograph showing calf muscle pseudohypertrophy. The patient had progressive symmetric muscle weakness associated with
elevated serum CK levels, myalgia, cramps, and stiffness after exercise
53
54
M. P. Zamorani and M. Valle
T
T
a
b
T
T
c
d
Fig. 3.11a–d. Neurogenic atrophy of muscles in two different patients with a,b recent-onset and c,d long-standing peroneal
neuropathy. a Transverse 12–5 MHz US image over the tibialis anterior muscle with b fat-suppressed T2-weighted MR imaging
correlation demonstrates normal volume and diffusely hyperechoic appearance of the muscle (arrowheads). The abnormal
echotexture is related to intramuscular edema (curved arrow). c Transverse 12-5 MHz US image over the tibialis anterior muscle
with d T1-weighted MR imaging correlation reveals decreased volume and hyperechoic appearance of the muscle (arrowheads).
Although similar to that seen in a, the abnormal echotexture reflects fatty atrophy (curved arrow). T, tibia
equipment settings (Bargfrede et al. 1999; Pillen
et al. 2003; Scholten et al. 2003). Apart from the
above limitations, US can be considered a useful
tool complementary to electrophysiology to provide information on muscle morphology, which is
beyond the scope of electrodiagnosis.
In patients with unilateral disorders, US images
of the affected muscle can be compared with those
of the unaffected side. In these cases, careful positioning of the transducer by surface landmarks is
needed to ensure symmetric imaging. Transverse
images are best suited for muscle measurements. In
patients with bilateral disorders, comparative US
evaluation should be conducted by selecting a control muscle in a healthy area, possibly with similar
degrees of overlying subcutaneous tissue. Finally,
when examining an atrophied fatty-infiltrated
muscle, the examiner must be aware that changes
may occur not only as a result of a denervation process but also following disuse or a complete tendon
tear (Yao and Metha 2003). Then the integrity of
the tendon belonging to the affected muscle must
be carefully assessed.
3.1.4
Traumatic Lesions
Based on their pathomechanism, muscle injuries
can be grouped into two main classes: extrinsic
and intrinsic. Extrinsic injuries result from external trauma, either a contusion or a penetrating
injury (laceration), whereas intrinsic injuries are
most often the result of contraction and simultaneous elongation of a given muscle. In the first class,
the location of the tear strictly matches the site of
the trauma. These lesions typically occur in areas
where the muscle is compressed between the applied
outer force (direct blow) and an underlying hard
bony surface (e.g., quadriceps muscles against the
femoral shaft). On the other hand, intrinsic ruptures
almost invariably lead to a disruption of muscle
fibers near the myotendinous junction, which is
considered the weakest ring of the muscle-tendonbone unit because it has less capacity for energy
absorption than the other structures (Palmer et
al. 1999). The myotendinous junction is the most
common site of partial or complete muscle injury
56
M. P. Zamorani and M. Valle
Clinically, muscle strain injuries can be classified
into a four-step grading system: grade 1 indicates
a tear affecting a small number of muscle fibers
with an intact fascia; grade 2 refers to a moderate
tear with the fascia remaining intact; grade 3 injury
is a tear of many fibers with partial tearing of the
fascia; grade 4 injury indicates a complete tear of
the muscle and the fascia (Ryan 1969). Healing and
recovery of function takes longer with a high-grade
injury, and the long-term outcome is generally worse
(Noonan and Garrett 1999). Initially, treatment of
a muscle strain injury includes rest, application of
ice, and compression for relieve of pain and swelling; nonsteroidal inflammatory drugs may also be
administered for pain relief in the first days after
trauma. After resolution of the acute pain and swelling, physical therapy performed avoiding excessive
fatigue and with adequate warm-up before exercise
may contribute to the restoration of muscle strength
and flexibility (Noonan and Garrett 1999). The
long-term outcome after muscle strain injury is
usually good and complications are rare.
Muscle strain injuries appear at US as avulsion
and retraction of muscle fibers from the tendon
or aponeurosis in which they attach (Fig. 3.12b,c)
(Bianchi et al. 1998). The examiner must be aware
that some muscles (e.g., rectus femoris) have a complex structure with internal tendons: in these cases,
the injury may occur in the mid-portion of the
muscle belly and not at its distal portion as may be
expected (Bianchi et al. 2002). US signs of muscle
tear include avulsion and proximal retraction of
the fibroadipose septa. In low-grade injuries, the
space between the retracted septa and the aponeurosis is filled with a hyperechoic area reflecting extravasation of blood and clots. These small
lesions may go unnoticed if an accurate scanning
technique with careful and systematic examination
of the distal portion of the fibroadipose septa is not
employed. On the other hand, larger muscle tears
are characterized by a more substantial blood collection which makes them easily detectable. This
does not occur immediately after the trauma, but
1–2 days later, when the collection tends to become
more hypoechoic. A widely accepted classification
of muscle injuries is based on a four-grade scale
(Peetrons 2002). Grade 0 injury corresponds to a
normal US appearance in spite of the presence of
local clinical findings; in grade 1 injury, subtle US
findings may be observed, including ill-defined
hyperechoic or hypoechoic intramuscular areas
or a swollen aponeurosis (Fig. 3.13); grade 2 and
grade 3 correspond to partial and complete muscle
tears, in which incomplete or full discontinuity of
the muscle occurs. In mild trauma, an early assessment with US can lead to false negative results
because the hematoma is diffuse and manifests as
scattered blurred hyperechoic areas within muscle
rather than as a focal well-defined hypoechoic collection: fat-suppressed T2-weighted MR imaging
is superior to US in depicting mild strains soon
after the trauma. During healing, the hemorrhagic
cavity shrinks and its walls progressively thicken
and collapse. The time at which the lesion is filled
in can be considered an indicator for restarting
low-level activity with care. However, this should
be only decided in the absence of clinical symptoms
and when a sufficient delay has occurred between
the injury and the resumption of sports activities
(never less than 4–6 weeks after the end of symptoms) (Peetrons 2002). In late phases, fibrous
scars are seen as blurred hyperechoic zones within
muscle: they are often observed in significant
trauma or when the sporting activity was resumed
too early (Fig. 3.14) (Peetrons 2002). Usually, scars
are weakly symptomatic, but the risk of recurrent
injury seems to be proportional to their extent in
the muscle.
3.1.4.2
Contusion and Laceration
Direct external trauma may result in local
hematoma, contusion, and partial and complete
muscle laceration. Although virtually all muscles
can be involved during sporting or recreational
activities, the most frequently injured are the
vastus intermedius and the vastus lateralis. These
anterior thigh muscles are particularly predisposed
to injury in athletes whose sports require direct
hard contact (e.g., soccer, football, rugby, and
hockey). The mechanism of injury often consists
of crushing of the muscle against the femoral shaft
by the knee of another player. Contusion injuries
following extrinsic trauma are depicted with US
as muscle swelling with focal irregularities and
echotextural changes. The muscle architecture is
no longer recognized as it is altered by disruption
of the muscle fibers and hematoma (Fig. 3.15a).
Depending on the overall strength of the applied
force, partial or complete tears can occur.
Abnormalities are typically located at the actual site
of trauma and not at the myotendinous junction:
this helps in distinguishing a contusion injury from
a muscle strain. If a large fluid collection is present,
Muscle and Tendon
a
b
∗
c
d
e
Fig. 3.13a–e. Myotendinous strains. Two different cases of central aponeurosis strain of the rectus femoris muscle following
minimal trauma. a,b Case 1. a Short-axis and b long-axis 12–5 MHz US images over the middle third of the rectus femoris
muscle demonstrate an ill-defined hyperechoic area (arrowheads) surrounding the aponeurosis related to edema and hemorrhagic changes. Note the normal-appearing external portion of the muscle (arrows). c–e Case 2. Short-axis 12–5 MHz US
images obtained from c proximal to e distal over the rectus femoris reveal progressive swelling and hypoechoic appearance
(arrowheads) of the central aponeurosis (straight arrows) and adjacent muscle fibers (curved arrow) with a small hematoma
(asterisk) reflecting a myotendinous strain
the muscle ends can be seen floating within the
hematoma. Closed muscle trauma by a sharp object
may be associated with laceration of the subcutaneous tissue. In these cases, the hematoma expands
vertically through the subcutaneous layer and the
muscle (Fig. 3.15b). A direct shock injury may also
result in disruption of the muscle fascia causing a
muscle hernia (Bianchi et al. 1995a; Beggs 2003).
In these patients, US demonstrates interruption
of the hyperechoic fascial layer and focal extrusion of muscle tissue within the subcutaneous
fat (see Chapter 15). Muscle lacerations are much
less common and are more often encountered
after trauma than after sports accidents. In these
instances, irrigation and debridement followed by
suture repair of the fascia is indicated.
3.1.4.3
Myositis Ossificans
There are three main complications of muscle tear:
cysts and myositis ossificans and, more rarely, calcific myonecrosis (Peetrons 2002). Intermuscular
and intramuscular cysts may be encountered after
muscle trauma as well-defined echo-free masses
with posterior acoustic enhancement. These cysts
have an elongated shape and represent the residue
of a local hematoma. Their most common location is
the calf (see Chapter 15). In selected cases, they may
require percutaneous needle evacuation. Calcific
myonecrosis is a space-occupying calcified mass
that typically develops in the anterior compartment of the leg late after a closed lower extremity
57
58
M. P. Zamorani and M. Valle
a
b
c
Fig. 3.14a–c. Healing rectus femoris strain. a Long-axis extended field-of-view and b short-axis 17–5 MHz US images of the
rectus femoris muscle in a patient with prior myotendinous strain reveal an intramuscular echogenic area (arrows) in proximity to the central aponeurosis (arrowheads) representing residual scar tissue. c Correlative axial gradient-echo T2*-weighted
MR image
s
s
m
m
m
a
b
Fig. 3.15a,b. Closed contusion trauma. Two different cases of thigh muscle injuries following blunt trauma by sharp objects.
a Transverse 12–5 MHz US image over the vastus lateralis (m) reveals an extensive laceration of muscle tissue filled in with
hypoechoic hematoma (arrowheads). Note the intact subcutaneous tissue (s). b Transverse 12-5 MHz US image over the medial
thigh demonstrates combined laceration of the subcutaneous tissue (s) and the gracilis muscle (m) with interruption of the
fascia (arrows). The defect is filled in with hypoechoic hematoma (arrowheads)
Muscle and Tendon
trauma, and is often seen in association with vascular injury or a compartment syndrome (Dhillon et
al. 2004). In this condition, the injured muscle may
be replaced with a complex mass consisting of a central cystic core containing necrotic muscle, fibrin,
cholesterol, and organizing thrombus, together with
a peripheral calcified rim. US demonstrates calcified
myonecrosis as an intramuscular extensive calcified
mass with posterior acoustic shadowing and may
help to guide the aspiration of the fluid component
as an aid in management (Batz et al. 2006). The
main differential diagnosis of calcific myonecrosis
is the more common myositis ossificans, given the
fact that the extensive calcified shell may mask the
internal fluid component at US examination.
Myositis ossificans is a benign self-limiting condition presenting as an intramuscular mass with predominant involvement of the large muscles of the
extremities, the large muscles of the thigh and the
anterior muscles of the arm being the most commonly
affected (Thomas et al. 1991). The term “myositis” is a
misnomer because this condition is not inflammatory.
It usually results from a severe contusion trauma or
chronic microtrauma, but may also be seen in patients
with other disease or may develop spontaneously.
There is, however, debate as to whether unrecollected
trauma is present in these cases. From the histologic
point of view, this condition exhibits a typical maturation pattern that allows a proliferative mesenchymal
response (early pseudosarcomatous phase) to evolve
toward formation of heterotopic mature bone. During
maturation of the lesion, a zonal pattern develops
with three concentric zones: the inner zone is characterized by areas of hemorrhage and necrotic muscle
with proliferating fibroblasts; the middle zone consists of immature osteoid formation and islets of cartilage preceding bone formation; and the outer zone is
formed by mature bone (Gindele et al. 2000). Peripheral bone formation usually starts 6–8 weeks after the
trauma, but it can occur earlier. In the late phase, the
lesion can ossify as a whole with formation of a cortex
and marrow spaces (Ackermann 1958). As it matures
the lesion regresses in size, disappearing spontaneously in approximately 30% of cases (Schulte et al.
1995). Development of peripheral calcifications is a
peculiar feature of myositis ossificans and makes this
condition more easily diagnosed with X-ray modalities, including plain films and CT, than with US and
MR imaging. In the early stages of disease (before the
sixth week of evolution), when formation of calcifications has not yet occurred, the imaging diagnosis is
not straightforward: it can be difficult to distinguish
lesions at this stage from a soft-tissue malignancy.
The US findings of myositis ossificans change
with the lesion’s age, reflecting the evolving histology (Fornage and Eftekhari, 1989; Peck and
Metreweli, 1988). Initially, the US appearance of
myositis ossificans has been described as that of an
intramuscular hypoechoic ovoid mass with an echogenic center, and even a so-called zone phenomenon
matching the maturation process has been reported
(Kramer et al. 1979; Thomas et al. 1991; Gindele et
al. 2000). In more detail, early lesions are characterized by a peripheral thin hypoechoic zone enveloping
a broader highly reflective zone within which a third
central hypoechoic zone is found (Fig. 3.16a) (Thomas
et al. 1991). With progressive maturation, the peripheral hypoechoic rim may become hyperechoic as a
result of increasing ossification: a sheet-like or eggshell-like calcified rim is considered very suggestive
of myositis ossificans (Peck and Metreweli, 1988).
Then, visualization of the lesion center and the separation of the lesion from the underlying bony cortex
may become more difficult because of the acoustic
shadowing from peripheral calcifications (Gindele
et al. 2000). The process of ossification is apparent
with US approximately 2 weeks earlier than with plain
radiographs (Peetrons 2002). Although the typical
pattern of calcifications is characteristic, we believe
that a standard radiograph must always be obtained to
confirm the diagnosis and to exclude more aggressive
calcified lesions, including paraosteal and soft-tissue
sarcomas (Fig. 3.16b,c). After surgical resection, US has
proved able to detect recurrence of myositis ossificans
and to differentiate this condition from extraosseous
sarcomas (Okayama et al. 2003).
3.1.5
Inflammatory and Ischemic Conditions
Inflammatory myopathies include a heterogeneous
group of acquired and potentially treatable disorders caused by an autoimmune process (idiopathic
inflammatory myosites) or infectious agents (pyomyositis). Among ischemic conditions, we focus
here mainly on diabetic muscle infarction and rhabdomyolysis. As previously stated, compartment syndromes are addressed in Chapter 15.
3.1.5.1
Idiopathic Inflammatory Myopathies
Based on their unique clinical, histopathologic,
immunologic, and demographic features, idio-
59
61
Muscle and Tendon
a
b
Fig. 3.17a,b. Polymyositis and associated scleroderma. a Long-axis and b short-axis 12–5 MHz US images over the medial head
of gastrocnemius reveal an intramuscular ill-defined hypoechoic area (arrows) with loss of the fibroadipose pattern, reflecting
edema and fatty tissue infiltration. The subcutaneous tissue appears normal
fications (Mulier et al. 1999; Wlachovska et al.
2004). This lesion has been described as having a
“scaffolding” pattern between continuous muscle
bundles on long-axis scans and a “checkerboard”
pattern on short-axis images (Sarteschi et al.
1997). Longitudinal US images may also demonstrate muscle swelling with preservation of the
normal fibrillar pattern, disrupted by hypoechoic
lines in a geometric shape, somewhat resembling
“dry cracked mud” (Fig. 3.18) (Pagonidis et al.
2005). Although imaging studies may suggest such
an inflammatory process (very rapidly growing
mass in a muscle compartment), incisional biopsy
is usually needed to rule out soft-tissue malignancy and to avoid radical excision.
Sarcoidosis, a systemic granulomatous disease,
may occasionally involve the skeletal muscles, leading to either palpable nodules or chronic progressive wasting and muscle atrophy or acute myositis
(Otake 1994; Tohme-Noun et al. 2003). The muscles of the proximal portions of the extremities are
predominantly involved. In nodular-type sarcoidosis, US is able to display well-defined hypoechoic
nodules elongated along the muscle fibers and to
guide percutaneous biopsy to the appropriate site
(Levine et al. 1996; Tohme-Noun et al. 2003). Histologic detection of noncaseating granulomas surrounded by normal muscle tissue allows a definitive
diagnosis. In large sarcoid nodules, a hyperechoic
center can be depicted with US (Otake 1994). In
patients with pulmonary sarcoidosis and painful
leg muscles, the possibility of muscular sarcoidosis should be taken into account by the examiner.
Color Doppler imaging may be helpful to rule out
phlebitis.
3.1.5.2
Pyomyositis, Abscess, and Hydatid Disease
Pyomyositis is a suppurative bacterial infection of
muscle, most commonly affecting the larger muscles of the lower limb (Chau and Griffith 2005).
This condition most often occurs in immunocompromised patients with HIV-AIDS or diabetes and
has a higher prevalence in tropical countries, where
it is responsible for 3–5% of all hospital admissions
(Canoso and Barza 1993; Trusen et al. 2003).
However, it may follow even minor blunt trauma
and local hematoma. The major causative agent is
Staphylococcus aureus followed by Mycobacterium
tuberculosis (psoas muscle infection following
tuberculous spondylodiscitis), and Streptococcus
pyogenes (Bickels et al. 2002). From the clinical
point of view, pyomyositis presents with or without fever, dull cramping pain for 10–21 days, and
localized muscle tenderness (Trusen et al. 2003).
The US appearance of infection of the muscles has
been described both in adults (Chau and Griffith
2005) and in children (Trusen et al. 2003). Initially
(inflammatory phase), US reveals muscle swelling,
a diffuse hyperechoic appearance reflecting edema,
and hyperemia (Fig. 3.19) (Bureau et al. 1999; Chau
and Griffith 2005). Small hypoechoic foci within
the abnormal muscle related to early necrosis and
small abscesses may be noted. At this stage, pyomyositis usually responds well to antibiotic therapy.
Later in the course of the disease, an overt muscle
abscess develops (suppurative phase).
Muscle abscesses appear as fluid collections with
well-defined posterior enhancement and variable
echotexture, ranging from hypoechoic to hyper-
Muscle and Tendon
∗
a
b
c
d
Fig. 3.19a-d. Pyomyositis in a 65-year-old man with fever and left thigh pain after sustaining blunt trauma to this area. a,b
Transverse a gray-scale and b color Doppler 12–5 MHz US images reveal a swollen vastus lateralis muscle with heterogeneous
echotexture consisting of increased echogenicity (arrows) as well as hypoechoic areas (asterisk) in which fibroadipose echoes
are lost or spaced out. Posterior to this abnormal area, muscle tissue retains a normal appearance (arrowheads). Diffuse intramuscular hyperemia is detected at color Doppler imaging. c,d Correlative axial c T1-weighted and d T2-weighted MR images
demonstrate marked hyperintense T2 signal and swelling of the vastus lateralis with irregular borders and diffuse fascial
involvement (arrows)
∗
∗
a
F
b
c
Fig. 3.20a–c. Muscle abscess. a Transverse 12–5 MHz US image over the anterior thigh in a middle-aged immunocompromised
patient with fever, pain, and local signs of infection with b T2-weighted and c Gd-enhanced T1-weighted MR imaging correlation shows a swollen heterogeneous vastus intermedius muscle (arrows) with internal fluid-filled areas (asterisks) and debris,
consistent with local abscess formation. F, femoral shaft. US-guided aspiration yielded purulent fluid that grew Staphylococcus
aureus up. Symptoms resolved with percutaneous drainage and antibiotic therapy
63
Muscle and Tendon
b
∗
a
c
d
Fig. 3.22a–d. Diabetic infarction. a Anteroposterior plain film of the right leg in a 60-year-old patient with diabetic infarction of
the distal lower extremity shows discrete soft-tissue swelling (arrows) in the anterolateral compartment musculature. b Longitudinal 12–5 MHz US image reveals a hypoechoic intramuscular area with deranged echotexture (arrows), which is limited to
the tibialis anterior muscle. c,d Axial fat-suppressed c gradient-echo T2* and d gadolinium-enhanced T1-weighted MR images
show diffuse edema of the tibialis anterior muscle (arrow) and a ring of high signal intensity after gadolinium administration
surrounding an unenhanced central core (asterisk)
the muscle fibers. As already described in Chapter 2, the term “hemangioma” encompasses a wide
spectrum of lesions from capillary forms to vascular malformations – including capillary, cavernous,
arteriovenous, venous, and mixed types – based on
the predominant type of vascular channel involved
(Olsen et al. 2004). In addition to their vascular
components, hemangiomas can contain thrombus,
calcification, hemosiderin, fat, smooth muscle, and
fibrous tissue, reactive fat being the most common
association. The variety of tissues found in muscular
hemangiomas explains their heterogeneous appearance. US demonstrates a complex ill-defined mass
within the affected muscle, characterized by a mixture of hypoanechoic and hyperechoic (reactive fat
overgrowth) components (Fig. 3.23) (Derchi et al.
1989). Prominent vascular channels can be identified
on gray-scale and Doppler imaging as well. One-toone correlation between US and MR images shows
good correspondence between intratumor hyper-
echoic areas and fat (high T1 signal), and hypoechoic components and blood-filled cavities (high T2
signal). Phleboliths within the mass are present in
approximately 50% of cases and are best identified
on plain films (Fig. 3.23f) (Murphey et al. 1995). At
US, they appear as bright dots with posterior acoustic
shadowing that are usually located within the hypoechoic component of the hemangioma. Doppler imaging characteristics of hemangiomas are described in
Chapter 2. Overall, US can diagnose hemangiomas,
especially when phleboliths are detected within the
mass. During prolonged observation, very slow blood
motion in the hypoechoic cavities of the mass can be
appreciated on gray-scale imaging, like a “swarming mass”. In some instances, however, the assessment of hemangiomas may be difficult: in particular,
the boundaries of the lesion are usually undefined,
especially in large masses infiltrating more than one
muscle or blending imperceptibly with the intermuscular fatty planes.
65
67
Muscle and Tendon
∗
b
∗
∗
∗
a
c
Fig. 3.24a–c. Intramuscular lipoma: infiltrative type. a Transverse 12–5 MHz US image over the anterior shoulder in a patient
with a painless slowly growing mass with b,c axial T1-weighted MR imaging correlation demonstrates a large mass within the
deltoid muscle characterized by a hyperechoic background (asterisks) and a striated pattern (arrowheads) due to intermingled
muscle fibers with fat. The lipoma is delimited by a thin hypoechoic rim (arrows) reflecting peripherally displaced muscle
tissue
fat, in our experience MR imaging is much superior to US for the confident identification of adipose
tissue in infiltrative lipomas.
After fibrous and fibrohistocytic malignancies,
liposarcoma represents the second most common
type of soft-tissue sarcoma, accounting for approximately 10–25% of all soft-tissue sarcomas (Murphey
et al. 2005). It is predominant in men around the
fifth and sixth decades of life and does not represent
the result of malignant transformation of a lipoma.
Histopathologically, liposarcomas are grouped in
five subtypes: well-differentiated, myxoid, round
cell, pleomorphic, and dedifferentiated. Well-differentiated liposarcoma is the most common type
(50%); it lacks metastatic potential but tends to recur
locally. US shows large, multilobulated, well-defined
masses which, in most cases, are indistinguishable
from mature lipomas (Fig. 3.25) (Futani et al. 2003;
Murphey et al. 2005). Based on gray-scale US findings, lipoma-like lesions with a complex appearance
(containing thick septa and nodular or globular foci
with echotexture other than that of fat) always merit
further investigation with contrast-enhanced MR
imaging (Fig. 3.26). Finding blood flow signals in
a lipoma-like mass with color and power Doppler
imaging should also alert the examiner (Bodner et
al. 2002; Futani et al. 2003). Unlike well-differentiated liposarcoma, myxoid liposarcoma presents as a
well-circumscribed multinodular mass whose gross
pathologic appearance includes a smaller volume of
fat (often <10% of the total) and a variable mixture
of myxoid and round cell components. US demonstrates a complex hypoechoic mass with posterior
acoustic enhancement, a nonspecific appearance
quite different from that of typical lipomas (Sung
et al. 2000). Based on the nonenhanced MR imaging
findings (high T2 signal related to the myxoid component), myxoid liposarcoma may often resemble
a cyst. This pitfall seems particularly likely in the
popliteal fossa, where the cyst-like mass may mimic
a Baker cyst. In these cases, US may be helpful in
revealing that the mass does not meet the criteria
for a cyst (Sung et al. 2000). Finally, the round cell,
pleomorphic and dedifferentiated forms are locally
aggressive tumors with high metastatic potential.
They show nonlipomatous components which may
be predominant with little or no fat (round cell and
pleomorphic). Accordingly, the US and MR imaging
diagnosis of these latter masses may be very difficult
due to their nonspecific appearance.
3.1.6.3
Intramuscular Myxoma
Intramuscular myxoma is a slowly growing benign
tumor composed of abundant myxoid deposits and
fibroblasts (Murphey et al. 2002; Luna et al. 2005).
Intramuscular myxomas primarily affect patients
40–70 years old with a female predominance, and
70
M. P. Zamorani and M. Valle
arise in the lower limb along the course of the sciatic
nerve, in the limb girdle, and in the shoulder area.
The term “desmoid” means a “tendon-like” lesion:
in fact, the lesion is composed of arrays of fibroblasts and varying amounts of dense collagen. After
their initial growth, most desmoids evolve into a
progressive shrinkage of the mass, with a decrease
in cellularity and volume of the extracellular spaces
until they become an irregularly shaped mass of
dense collagen tissue (Vandervenne et al. 1997).
Accordingly, the MR imaging signal intensity pattern of desmoids varies with time, likely reflecting
the different proportions of cellular tissue, myxoid
tissue, and collagen (Vandervenne et al. 1997).
Scant experience is reported in literature on the
US features of extra-abdominal desmoids: these
masses usually extend along the fascia and engulf
muscle fibres, have variable echogenicity (depending on the degree of cellularity, water content and
a
d
collagen), and ill-defined or sharp boundaries
(Fig. 3.28a–c) (Mantello et al. 1989; Casillas et
al. 1991). A faint fibrillar echotexture and posterior acoustic attenuation reflecting dense collagen
tissue is often detected. Doppler imaging may demonstrate both a hypervascular and a hypovascular
pattern: in general, lesions with abundant collagen are hypovascular. Although strikingly similar to other types of extra-abdominal desmoids in
terms of both their histopathologic and imaging
features, desmoid tumors of the abdominal wall
are considered a distinct entity due to their definite relationship with women taking birth control
pills (estrogen-sensitive tumor), pregnancy (during
or following), abdominal surgery, and trauma. In
addition, they may be part of the familial Gardner
syndrome. These tumors most commonly arise in
the rectus abdominis and oblique external muscles
(Fig. 3.28d,e) (Robbin et al. 2001).
b
c
e
Fig. 3.28a–e. Intramuscular desmoids: spectrum of US appearances. a–c Extra-abdominal desmoid of the popliteal fossa. a
Longitudinal 12–5 MHz US image over the medial head of gastrocnemius with b transverse fat-suppressed T2-weighted and
c transverse gadolinium-enhanced fat-suppressed T1-weighted MR images demonstrates an intramuscular solid hypoechoic
mass (arrowheads) with some faint fibrillar pattern elongated along the major axis of the gastrocnemius. At MR imaging, the
mass (arrow) has heterogeneous high signal intensity on the T2-weighted image, which corresponds to increased cellularity, and
is characterized by prominent bands of low signal intensity, likely related to the dense areas of collagen. d,e Desmoids of the
abdominal wall. Two different cases observed in young women d taking birth control pills and e in the postpuerperal period.
d Transverse 12–5 MHz US image over the left rectus abdominis muscle reveals an intramuscular ill-defined heterogeneously
hypoechoic mass (arrowheads). e Longitudinal extended field-of-view 12–5 MHz US image demonstrates a large hypoechoic
mass (arrowheads) with irregular margins, infiltrative growth, and aggressive behaviour arising from the right rectus abdominis
muscle (arrows)
Muscle and Tendon
3.1.6.5
Rhabdomyosarcoma and Metastases
Rhabdomyosarcoma is the leading primary malignant tumor of striated muscle. It is extremely
aggressive and has high potential for local invasion, early recurrence, and metastases. The tumor
occurs throughout childhood and adolescence with
two peaks of incidence between 2 and 6 years and 14
and 18 years. There are two main histotypes: embryonic (botryoid) and alveolar (anaplastic), the latter
more commonly arising from the muscles of the
extremities and characterized by a worse prognosis
(Cohen et al. 1996). The diagnostic imaging investigation of rhabdomyosarcoma is essentially based
on MR imaging. With this technique, the tumor is
usually isointense to muscle on T1-weighted images
and has high signal intensity on T2-weighted images
(McCarville et al. 1999). After gadolinium administration, heterogeneous enhancement is usually
observed related to necrotic areas. The US imaging
features of rhabdomyosarcoma lack specificity; in
these patients, the role of US is limited to guiding
percutaneous biopsy.
In clinical experience, the incidence of intramuscular metastasis from malignant tumors is low.
Many factors (e.g., contractile activity, local changes
in pH and oxygenation, accumulation of lactic acid,
intramuscular blood flow volume and pressure,
local temperature) are claimed to possibly interfere
with the intramuscular growth of secondary tumors
(Williams et al. 1997). However, the real prevalence
of striated muscle metastases in autopsy series of
patients who harbored malignancy at the time of
death is much higher (16%) than expected (Pearson
1959). The reason for such a discrepancy is probably
related to the fact that these lesions are painless and
may not be detected when they are small (Chen et
al. 2005). Primary tumors that most often spread to
skeletal muscles are carcinomas of the breast, colon,
and lung (Chen et al. 2005). Although the diagnosis may be suspected based on the clinical history,
US imaging lacks specificity to show the histologic
origin of the tumor, which can be established only
by means of needle biopsy (Fig. 3.29) (Rubens et
al. 1997; Yang et al. 1999; Ahuja et al. 2000; Chen
et al. 2005). Finally, one should remember that USguided percutaneous procedures for biopsy and
thermal ablation of abdominal tumors may cause
needle-tract seeding of tumor cells in the subcutaneous tissue and the muscles of the abdominal wall
(Kanematsu et al. 1997; Kim et al. 2000). This complication is not negligible and seems related to the
number of needle passes and the needle size (Kim
et al. 2000).
3.2
Tendon
3.2.1
Histologic Considerations
Tendons are a critical link in the musculoskeletal
system, acting to connect muscle to bone. They are
made of type 1 collagen (approximately 70% of dry
weight) embedded in an extracellular matrix and
are characterized by high tensile strength, similar to
that of bone (Erickson 1997). It has been estimated
that a cross-sectional area of 1 cm2 of tendon tissue
is able to support a load of up to 1 tonne (Erickson
1997). In tendons, collagen has a complex arrangement, made up of highly ordered bundles of fibers
grouped into fascicles. Most fibers have a course
longitudinal to the tendon axis; some, however,
may assume transverse and spiral arrangements
(Sharma and Maffulli 2005). This configuration
of collagen leads to the higher tensile strength and
reinforcement of the attachment sites of tendon.
Endotendineum and peritendineum – composed
of loose connective tissue, elastic fibers, and small
vessels – envelop the collagen bundles and are in
continuity with the epitendineum, a dense connective tissue layer tightly bound to the outer tendon
surface.
Tendons can be divided into two main classes: tendons with a straight path (type 1) and tendons that
redirect their course across synovial joints before
reaching their insertion (type 2). These two types
have different envelopes in order to reduce friction
during movements. Type 1 tendons are surrounded
by the paratenon, a loose areolar and adipose tissue
envelope that provides vessel pedicles entering the
tendon substance at intervals along the tendon
length and distributing longitudinally within the
endotendineum (Fig. 3.30a). The paratenon blends
with the epitendineum to form the peritendon. Type
2 tendons are covered by a synovial sheath with a
cell lining identical to the synovium (Fig. 3.30b).
This sheath is a complex structure composed of
two interconnecting layers: an internal, visceral one
covering the epitendineum and an external, parietal layer in continuity with the adjacent connective
spaces (Erickson 1997). The sheath is infolded by
the tendon, so that both visceral and parietal layers
71
Muscle and Tendon
T
∗
∗
a
b
∗
Bone
c
T
d
T
T
∗
T
e
∗
T
f
Fig. 3.30a–f. Tendon envelopes and retinacula. a Schematic drawing and d corresponding short-axis 12–5 MHz US image of a
type 1 tendon (T) invested by paratenon. In the US image, the peritendon (arrowheads) is demonstrated as a thin hyperechoic
envelope that can be distinguished from the surrounding fat (asterisk). b Schematic drawing and e corresponding short-axis
12–5 MHz US image of a type 2 tendon (T) invested by synovial sheath in patient with serous tenosynovitis. The presence of
anechoic synovial effusion (asterisks) allows accurate depiction of the synovial sheath, which consists of a combination of visceral (white arrowheads) and parietal (open arrowheads) layers, and the mesotendon (curved arrow). c Schematic drawing and f
corresponding short-axis 12–5 MHz US image of the flexor digitorum tendons (T) of the fingers shows the normal appearance of
an annular pulley (arrows), a retinaculum which prevents bowstringing of the underlying tendons during flexion of the fingers.
Note that the superficial portion of the pulleys has a hyperechoic, fibrillar appearance due to the perpendicular incidence of the
US beam, whereas its lateral portions are hypoechoic as a result of anisotropy. Arrowhead, phalangeal bone
US beam and become more clearly visible and better
separated one from another as the transducer frequency increases. At higher frequencies, fibrils have
a higher reflectivity and become thinner and more
numerous (Martinoli et al. 1993). On short-axis
planes, US demonstrates the normal tendon echotexture made up of bright stippled clustered dots
instead of the linear fibrillar echoes (Fig. 3.31b). Histologic correlation has demonstrated that the linear
echoes visible within tendons depend on the acoustic interfaces at the boundaries of collagen bundles
and endotendineum septa, based on their different histologic composition (Fig. 3.31c) (Martinoli
et al. 1993). Given the highly ordered structure of
superimposed planes of collagen and septa, tendons
are strongly anisotropic structures at US examination, and the fibrillar echoes can be demonstrated
with efficiency only when the US beam is perpendicular to them (Fornage et al. 1987; Fornage and
Rifkin 1988). Even a slight obliquity of the angle
of incidence can result in an artifactual decreased
echogenicity which may obscure textural details and
even mimic tendinous disease (Fig. 3.31d,e). In practice, this occurs if a curved rather than linear-array
transducer is used, or when tendons with a curvilinear shape (i.e., rotator cuff) or oblique orientation
to the skin surface (i.e., distal biceps tendon) are
examined. The epitendineum can be seen as a reflective line surrounding the tendon. Tendons which
derive from one muscle have a uniform fibrillar
pattern. Additional intratendinous details may be
appreciated in tendons which originate from one or
more muscles. In the Achilles tendon, for instance,
the convergent contributions from the two heads of
the gastrocnemius and the interface between them
(posterior) and the soleus (anterior) can be visualized as central thickened echoes due to the union
of respective peritendinous envelopes (Bertolotto
et al. 1995); in the quadriceps tendon, a trilaminar
complex made up of distinct superficial (from rectus
femoris), intermediate (from vastus medialis and
lateralis), and deep (from vastus intermedius) layers
73
75
Muscle and Tendon
of the muscle. Flexible stand-off pads or generous
amounts of gel must be used for assessment of tendons that wrap around curvilinear joint surfaces.
However, when bony prominences or narrow spaces
preclude an adequate alignment of the probe on the
long axis of tendon, US evaluation may be performed
on short-axis planes. Although these planes do not
allow depiction of the linear fibrillar echoes, tendons
may reliably be identified as well, based on the critical
variation in their echogenicity that can be induced by
rocking the probe back and forth. Systematic scanning on short-axis planes has the further advantage
of better depicting the relationships of tendons with
adjacent structures, as well as confirming the presence and extent of pathologic findings. In addition,
when multiple tendons run adjacent one to the other
through a restricted space or across a joint, it is easier
to distinguish each individual tendon on short-axis
planes. Dynamics of tendon motion during joint
activity or muscle contraction can be evaluated with
US in real time, and this may be essential to rule out
tendon abnormalities, to differentiate partial from
complete tears, as well as to assess the status of a
postoperative tendon.
3.2.3
Tendon Instability
Dislocation occurs in tendons invested by synovial
sheath, following the injury of one or more restraining structures of an osteofibrous tunnel, such as
ligaments, retinacula, and annular pulleys. A wide
spectrum of mechanical injures, ranging from violent acute trauma to repetitive minor damage may
lead to instability of certain tendons as they reflect
within osteofibrous tunnels: congenital hypoplasia
of the bony groove or laxity of the fibrous roof of
the tunnel may predispose to tendon instability
(Fig. 3.32a). US evaluation may reveal the degree
of tendon instability (i.e., intermittent subluxation,
permanent subluxation, dislocation) as well as a
number of associated findings, such as peritendinous effusion related to tenosynovitis or lesions in
the tendon substance due to abnormal friction of the
displaced tendon against bony edges (Fig. 3.32b,c).
Dynamic examination may enhance detection of
intermittent subluxation and assess whether spontaneous reduction is possible. The dynamic imaging
afforded by US appears to be well suited for such
T
a
∗
MH
d
b
T
MH
c
e
Fig. 3.32a–e. Tendon instability. a Schematic drawings illustrate congenital causes of tendon instability. On the left, the tendon
(T) is stabilized within its bony groove by a retinaculum (arrowheads). Tendon instability can be observed in cases of flat bony
groove (center) or laxity of the retinaculum (right). b Schematic drawings illustrate the different grades of instability of a tendon
relative to its bony groove (asterisk): intermittent subluxation (left), permanent subluxation (center) or dislocation (right). The
boundary of the groove is indicated by the vertical dashed line. c Schematic drawings illustrate the main abnormalities occurring in tendons (T) invested by a synovial sheath (arrowheads) during subluxation, including reactive tenosynovitis (center)
and partial tear (right). d,e Intermittent subluxation of finger extensor tendon. Transverse 12–5 MHz US images of the knuckle
of the middle finger in a patient with injury to the metacarpophalangeal joint and rupture of the sagittal band, acquired d
while the hand was extended and e in the clenched fist position. With the finger extended, the extensor tendon (arrow) lies in
a normal position with respect to the dorsal metacarpal head (MH); with the fist clenched, there is anterior dislocation of the
tendon on the ulnar side of the bone (dashed-line)
76
M. P. Zamorani and M. Valle
evaluation, especially in cases of subluxation, where
this technique is more efficient and easier than MR
imaging obtained with varied positioning. Permanent dislocations may readily be identified on static
scans, whereas intermittent subluxation requires
dynamic examination to assess whether spontaneous reduction is possible. Systematic scanning on
short-axis planes is preferred for assessing the instability of tendons, because both the empty tunnel
and the displaced tendon can be demonstrated in a
single image. In the appropriate chapters, peculiar
US features are described in detail for the instability of the long head of the biceps tendon (Farin
et al. 1995; Ptasznik and Hennessy 1995; Prato
et al. 1996; Martinoli et al. 2003), the peroneal
tendons (Fessell et al. 1998; Magnano et al. 1998;
Neustadter et al. 2004), the posterior tibial tendon
(Prato et al. 2004), and the flexor (Klauser et al.
1999; Hauger et al. 2000; Martinoli et al. 2000;
Klauser et al. 2002; Martinoli et al. 2005) and
extensor (Lopez-Ben et al. 2003) tendons of the fingers (Fig. 3.32d,e).
behind a retinaculum as well as excessive frictional
forces against bony surfaces or adjacent accessory
tendons can contribute to tendon damage at other
levels also (Fessell and van Holsbeeck 1999). In
addition, abuse or local injection of corticosteroids
and systemic disorders, such as systemic lupus erythematosus, gout, rheumatoid arthritis, diabetes,
hyperparathyroidism, and chronic renal failure, can
cause a detrimental effect on the strength of tendons
and predispose them to rupture. The quadriceps and
patellar tendons, the extensor and flexor digitorum
tendons and the posterior tibial tendon are primarily
involved by systemic disorders. Most likely, some
combination of trauma and predisposing factors,
either mechanical or biochemical, is the initial cause
of the degenerative process in tendons (Campbell
and Grainger 2001). Then, a continuum exists with
degenerative changes and minor intrasubstance tear
leading to partial and complete rupture (Jacobson
and van Holsbeeck 1998).
3.2.4.1
Tendinosis and Partial Tears
3.2.4
Degenerative Changes and Tendon Tears
In an intact musculotendinous system, tendon ruptures are infrequent and typically develop at the
insertion of tendon into bone, with or without avulsion of a small osseous fragment, or at the myotendinous junction, as a result of significant trauma
or an excessive rate of loading. On the contrary,
given the tough, fibrous nature of tendons, intrasubstance ruptures rarely occur outside the setting of
predisposing degenerative changes that weaken the
strength of the tendinous structure (Kainberger et
al. 1997). Several theories have attempted to explain
the degenerative process in tendons. Intrasubstance
degeneration may derive from overuse injures,
such as occur in certain sports (i.e., swimming,
golf, tennis, running, basketball, and ballet dancing) in which repetitive submaximal loading and/or
eccentric mechanical forces create recurrent microtrauma with microfailure of collagen bundles that
do not heal completely, especially in the vulnerable
areas where tendons exhibit reduced blood flow
(Herring and Nilsson 1987). The supraspinatus,
long head and distal biceps, extensor and flexor
tendons about the elbow, patellar and Achilles tendons, tibialis posterior and flexor hallucis longus
tendons are more frequently involved by overuse
damage. However, constriction or compression
Although painful tendinopathy is often called
“tendinitis,” this term is actually a misnomer. In
fact, these tendons are characterized by a degenerative noninflammatory process that is best termed
“tendinosis” (Khan et al. 1996; Campbell and
Grainger 2001). From the histopathologic point
of view, the damage to collagen which occurs in
tendinosis derives mainly from hypoxic and myxoid
degeneration and leads to deposition of interfibrillar glucosaminoglycans (Khan et al. 1996; Movin
et al. 1997; Schweitzer and Karasick 2000). The
first process is likely caused by ischemia because
of critical zones of hypovasculature in tendons; the
second reflects deposition of large mucoid patches
and vacuoles between the thinned degenerated
fibers. In most patients, the two processes coexist
and are associated with spontaneous tendon rupture
(Schweitzer and Karasick 2000).
As regards the location of the degenerative areas,
the increased risk of certain anatomic sites for development of tendinosis has led to the concept of critical zones, in which several factors, such as aging,
hypovascularization, and biomechanical effects in
combination with repetitive trauma, play a specific
causative role (Kainberger et al. 1997; Schepsis et
al. 2002). In the Achilles tendon, for example, the predominant involvement of its middle third has been
attributed to the fact that this is an area of low vas-
77
Muscle and Tendon
culature at the watershed between two separate vascular networks which converge toward the middle
from the myotendinous and the teno-osseous junction (Kainberger et al. 1997). Other biomechanical
factors may be implicated in the involvement of the
middle third of the Achilles tendon, such as the difference in tension between the gastrocnemius and soleus
fibers, which fuse to become one tendon only about
5–6cm from the calcanear insertion (Kainberger
et al. 1997). Then, the fibers around the medial portion of the tendon are specifically involved in patients
with hyperpronation of the foot, such as subjects with
marked forefoot varus, due to eccentric shear forces
across medial tendon fibers (Fig. 3.33a) (Gibbon et
al. 2000). On the other hand, in distal third Achilles
tendinopathy, abnormalities most often involve the
deep tendon surface as a probable result of the biomechanical conflict between these fibers and the posterosuperior angle of the calcaneus in full dorsiflexion
(Fig. 3.33b) (Gibbon et al. 2000). In “jumper’s knee,”
the deep central portion of the proximal insertion of
Lat
the patellar tendon is most often involved: somewhat
similar to insertional Achilles tendinopathy, microtrauma occurring between the undersurface of the
patellar insertion and a prominent patellar tip has
been assumed to be a causative factor for chronic
impingement and development of secondary degenerative changes (Khan et al. 1996). At the elbow, in
the common extensor tendon, the fibers of the extensor carpi radialis brevis lie deep, just over the lateral
ulnar collateral ligament, whereas the contribution
from the extensor digitorum communis is superficial.
Based on such anatomic consideration, some authors
have speculated that the most common abnormalities of lateral epicondylitis involve the origin of the
extensor carpi radialis brevis and, to a lesser extent,
the anterior aspect of the extensor digitorum tendon
(Connell et al. 2001).
From the clinical point of view, tendinosis typically presents with tendon swelling, tenderness, and
absent or moderate pain aggravated by activities
and the coexistence of tenosynovitis (Fornage and
∗
Med
a
LE
Calcaneus
b
LE
RH
RH
c
d
Fig. 3.33a–d. Tendinosis: spectrum of US appearances. a Short-axis 12–5 MHz US image over the middle third of the Achilles
tendon (arrows) in a 35-year-old man with marked hyperpronation of the foot demonstrates selective involvement of the medial
tendon fibers (arrowheads). b Long-axis 12–5 MHz US image of the distal third of the Achilles tendon reveals selective involvement the deep tendon fibers (arrowheads) and retrocalcaneal bursitis (asterisk) probably as a result of chronic conflict with the
posterosuperior angle (arrow) of the calcaneus during dorsiflexion. c,d Long-axis c gray-scale and d color Doppler 17–5 MHz
US images of the common extensor tendon attachment on the lateral epicondyle (LE) in a 40-year-old tennis player demonstrate
focal hypoechoic intratendinous changes and disappearance of the fibrillar echoes (arrowheads), signs that are typical of lateral
epicondylitis. Color Doppler imaging reveals a hypervascular pattern in the intratendinous hypoechoic area. RH, radial head
78
M. P. Zamorani and M. Valle
Rifkin 1988; Schepsis et al. 2002; Premkumar et
al. 2002). US demonstrates degenerative changes as
focal (nodular) or diffuse tendon thickening, and
intratendinous hypoechoic areas with loss of the
fibrillar echoes, reflecting a disorganized structure
of the collagen bundles (Fig. 3.33a–c) (Fornage et
al. 1984; Maffulli et al. 1990b; Martinoli et al.
1993; Åström et al. 1996; Grassi et al. 2000). As US
technology progresses, new developments in signalprocessing software, such as compounding technology, are leading to a continuing improvement of
image contrast and detail resolution. The result is
an improved delineation of fine pathologic findings
within degenerated tendons. This contributes to a
more confident differentiation between normal and
pathologic states and to a more reliable use of this
technique. Care must be taken, however, in determining the true pathologic meaning of these subtle
changes in the tendon substance, since minor abnormalities can be found also in asymptomatic tendons
of aged individuals (Martinoli et al. 1999).
Abnormally thickened tendons with altered
echotexture (focal hypoechoic areas) may exhibit
a hypervascular pattern at color and power Doppler imaging (Fig. 3.33d) (Weinberg et al. 1998;
Öhberg et al. 2001; Terslev et al. 2001; Richards
et al. 2001, 2005; Silvestri et al. 2003). Tendinosisrelated neovasculature is typically appreciated in
relation to the thickened part of the tendon, both
inside and outside it (Öhberg et al. 2001; Peers
et al. 2003). It appears significantly enhanced by
activity of the tendon before imaging (Cook et
al. 2004). As regards the significance of increased
blood flow within tendons, a positive correlation
seems to exist between the overall number of vessels detectable and the tendon size; painful tendinosis typically appears more hypervascular than
asymptomatic tendinosis, whereas no correlation
has been found between microvascular response
and duration of symptoms (Öhberg et al. 2001;
Richards et al. 2005). In any case the meaning of
the hypervascular pattern – whether it is causative
of tendon abnormalities or secondary to attempts
at healing – has yet to be defined (Richards et al.
2005). In terms of patient outcome, a hypervascular pattern detected at color and power Doppler
imaging is not an unfavorable sign (Zanetti et al.
2003); as seen on gray-scale US, tendon heterogeneity seems more likely related to a worse clinical
outcome after conservative treatment (Nehrer et
al. 1997; Archambault et al. 1998). US-guided
interventional procedures to treat chronic painful
tendinosis are detailed in Chapter 18.
Tendon heterogeneity on gray-scale US images
does not necessarily mean tendinosis-related
changes, but it may also reflect a partial tendon tear
(Martinoli et al. 1999; Jacobson et al. 1999). An
abrupt demarcation between degeneration, microtears, and interstitial tears is misleading, because
these forms reflect, in themselves, a continuum
of the same disease process and, in many cases,
coexist and are treated identically (Campbell and
Grainger 2001). With progress in US technology,
interstitial tears can be identified in areas of tendon
degeneration as thin hypoechoic clefts oriented along
the long axis of the tendon and possibly reaching the
tendon surface (Figs. 3.34, 3.35) (Connell et al. 2001;
Campbell and Grainger 2001; Premkumar et al.
2002). Progressive tearing leads to contour irregularities or focal thinning (Chen and Liang 1997).
Partial tears occur in the longitudinal orientation,
parallel to the course of the tendon (longitudinal
splits, fissurations) or in the transverse direction,
perpendicular to the tendon fibers (Diaz et al. 1998;
Bianchi et al. 2005, 2006). On a more macroscopic
level, partial tendon tear may involve macroscopic
amounts of fibers, and even produce discontinuities
in individual portions of complex tendons (Bianchi
et al. 1994a). US evaluation demonstrates both the
intact and the retracted ruptured portions of tendon
in association with a hematoma (Kalebo et al.
1990, 1992). The longitudinal fibrillar pattern is lost
in the fractured part of the involved tendon, but it
remains unaffected in the intact part (Fig. 3.35a,b)
(Martinoli et al. 1993). Lack of tendon retraction is
the most important feature for distinguishing partial from complete rupture.
In specific clinical settings, tendons may be
involved by metabolic disorders. In gout, deposition
of urate tophi in the Achilles tendons may result in
intratendinous nodules or diffuse thickening of the
tendon, while in heterozygous familial hypercholesterolemia, US can depict bilateral intratendinous
xanthomas in grossly enlarged Achilles tendons as
focal or diffuse hypoechoic areas before they become
apparent at physical examination (Kainberger
et al. 1993; Bude et al. 1993, 1994, 1998; Bureau
et al. 1998). This condition closely mimics highgrade hypoxic tendinosis. Calcifications may infrequently be encountered in tendons, although their
relationship with tendon degeneration is unclear.
Calcific deposits appears as linear echoes located
preferentially at the insertion of tendon into bone
(enthesis), reflecting a process of calcium hydroxyapatite or calcium pyrophosphate dihydrate crystal deposition. In predisposed subjects, extensive
82
M. P. Zamorani and M. Valle
∗
∗
B
B
b
∗
a
c
Fig. 3.38a–c. Complete tendon tear. a Long-axis 12–5 MHz US image over the anterior elbow with b schematic drawing and c
sagittal fat-suppressed T2-weighted MR imaging correlation shows a fluid-filled defect (asterisk) and the retracted proximal
tendon end (curved arrow) of a ruptured distal biceps tendon. The tendon is shrunk and characterized by posterior acoustic
attenuation (straight arrows), findings that are consistent with a complete tear. Note the retracted myotendinous junction of
the biceps muscle (B)
chronic tearing, the absence of fresh hemorrhagic
fluid and the organized hematoma which fills the
defect with echogenic material can be misleading,
mimicking tendon integrity (Fig. 3.39). In synovial
sheath tendons, an accurate scanning technique may
be required to visualize the tendon ends, which can
be retracted at a variable distance from the site of the
tear, and to measure the amount of tendon retraction on longitudinal scans. If there is no retraction
and the torn tendon ends are curled up, or if fluid
does not fill the space created by the tear, gentle passive assisted movements can be helpful to enhance
the separation of the tendon ends during stretching
(Kainberger et al. 1997).
In a degenerative setting, intense muscle contraction or abnormal stress forces exerted on healthy
tendons may lead to avulsions at their sites of insertion into bone. These tears often lead to detachment
and retraction of a bony fragment which remains
embedded in the tendon. Avulsion injuries typically
involve the supraspinatus tendon, causing retraction of a fleck of bone from the greater tuberosity,
the peroneus brevis, leading to avulsion of the base
of the fifth metatarsal, the flexor and extensor digi-
∗
C
PM
∗
Talus
a
b
Fig. 3.39a,b. Chronic nonoperated Achilles tendon tear. a Long-axis extended field-of-view 17–5 MHz US image over the posterior ankle in a patient who suffered an acute Achilles tendon rupture 1 year previously as a result of a bicycling injury with
b sagittal T1-weighted MR imaging correlation demonstrates a gap of approximately 6 cm between the proximal (star) and
distal (asterisk) blunt tendon ends. There is debris between the torn tendon ends and posterior herniation of the pre-Achilles
fat (curved arrow) within the defect created by the tear. Note the fusiform, blunt contraction of the distal tendon segment. PM,
posterior malleolus; C, calcaneus
83
Muscle and Tendon
torum tendons, which may detach a small cortical
fragment from the base of distal phalanx, and the
triceps tendon, leading to an olecranon fracture
(Fig. 3.40). The size and degree of displacement of
the avulsed bony fragment is variable. As avulsion
fractures are most commonly encountered in children and adolescents, tendon avulsion injuries are
addressed in detail in Chapter 19.
After surgical repair for a tendon tear, US imaging can help to monitor the healing process as
well as to rule out recurrent tears (Campbell and
Grainger 2001; Müller et al. 2002). Common
postoperative findings include altered tendon size
with areas of thickening or thinning, regardless
of the time of follow-up, and permanent abnormal
echotexture at the site of the tear. Although echotextural changes may partially regress with time,
they persist for many years after surgery (Rupp et
al. 1995). Heterotopic ossification may occasionally
occur. In type 1 tendons (i.e., Achilles tendon), the
paratenon becomes thickened and cannot be differentiated from the tendon tissue, thus leading to contour irregularities; the tendon gliding mechanism is
often impaired or limited (Rupp et al. 1995). Dynamic
scanning is essential in the postoperative evaluation
of type 2 tendons as a means to assess tendon gliding
function within the sheath and to exclude possible
adhesions. Intratendinous sutures appear as bright
double linear echoes (rail-like lines) due to highamplitude reflection of the US beam with posterior
reverberation artifact (Maffulli et al. 1990a; Rupp
et al. 1995). After repair of avulsion injuries, suture
anchors can be depicted as small defects of the cortical bone filled with bright material with posterior
reverberation artifact. During the healing process,
however, these signs seem to have limited value with
regard to evaluation of the functional results, such
as muscle strength, endurance, and range of motion
(Rupp et al. 1995; Müller et al. 2002). Recurrent
rupture may manifest with partial disruption of the
tendon fibers up to complete breakdown of the anastomosis (Fig. 3.41). In these cases, tendon thickening
with intratendinous hematoma or tendon thinning
with abundant fluid in the tendon sheath may indicate a small recurrent tear. In complete recurrent
tears, tendon discontinuity may be associated with
sutures floating freely within the hematoma.
3.2.5
Inflammatory Conditions
Although less common than degenerative processes,
some pathologic conditions in tendons are actually
inflammatory in nature, and distinguishing these
forms from simple tendinosis is important because
the clinical management may differ. Although
degenerative and inflammatory conditions may
be treated with the same conservative measures
(i.e., rest, ice, and nonsteroidal anti-inflammatory
drugs), inflammatory lesions that fail to regress
require more aggressive therapy with corticosteroids or even surgical procedures. The spectrum of
US findings depends on the type of tendon involved,
∗
O
Humerus
a
b
Fig. 3.40a,b. Acute avulsion-type injury of the medial head of the triceps tendon. a Long-axis 12–5 MHz US image over the
posterior elbow with b plain film correlation demonstrates a ruptured retracted medial head of the triceps tendon (arrowheads)
containing a fragment of bone (arrow) within, as a result of avulsion trauma from the olecranon process (O). The retracted,
thickened proximal tendon is seen surrounded by mild hypoechoic fluid (asterisk)
84
M. P. Zamorani and M. Valle
2
1
a
b
1
∗
∗
∗
1
∗
∗
∗
2
2
c
Fig. 3.41a–c. Postsurgical tendon retear. Two different cases. a,b Achilles tendon retear. a Long-axis gray-scale and b color Doppler 12–5 MHz US images show complete retear of a previously sutured Achilles tendon. The swollen tendon ends (1, 2) are
separated by a wide gap filled with debris and fluid. Note the surgical stitches (arrowheads in a) lying free within the gap. Local
blood flow signals (arrowheads in b) surround the tendon ends reflecting local hyperemia. c Extensor pollicis longus tendon
retear. Long-axis 12–5 MHz US image over the dorsoradial aspect of the hand with schematic drawing correlation (insert)reveals
a fluid-filled gap (asterisks) between the two retracted ends (1, 2) of the extensor pollicis longus tendon. Note the disconnected
surgical stitches (arrowheads) attached to the tendon ends that float freely within the empty tendon sheath. A split-screen image
was used, with the two screens aligned for an extended field of view
as well as on the associated changes occurring in the
tendon envelopes and associated synovial bursae.
The inflammatory process mainly results in “peritendinitis” for tendons invested by paratenon (type
1) and “tenosynovitis” for tendons invested by
synovial sheath (type 2). For both processes, the
functional meaning is somewhat equivalent. Peculiar conditions, such as calcifying tendinitis, are
addressed elsewhere (see Chapters 6, 18).
3.2.5.1
Paratendinitis and Attrition Bursitis
Paratendinitis (peritendinitis) most often occurs in
the Achilles tendon in association with high-grade
hypoxic tendinosis during phases of exacerbation
of disease (Fig. 3.42a) (Schweitzer and Karasick
2000). Clinically, paratendinitis is accompanied by
diffuse discomfort and peritendinous swelling and
tenderness (Schepsis et al. 2002). Fluid within and
patchy thickening of the paratenon, irregularities of
tendon margins, and adhesions are typically found
(Gibbon et al. 2000; Martinoli et al. 1999). In the
less common isolated paratendinitis (without tendinosis), the Achilles tendon itself is normal while the
peritendinous tissues show edematous changes and
tender nodules related to localized connective tissue
hypertrophy (Fig. 3.42b,c). Acutely, this condition is
encountered in long-distance (marathon) runners
as a result of abnormal biomechanics; it may also
follow training errors, including a sudden increase
of exercise and change of terrain, particularly hillrunning.
Paratendinous bursae (e.g., the retrocalcaneal
bursa at the heel, the deep infrapatellar bursa at
the knee, and the bicipitoradial bursa at the elbow)
primarily act as shock absorbers by reacting to
increased compression and frictional forces exerted
by the overlying tendons (Gibbon and Wakefield
1999). In most cases, intrabursal fluid or synovial
hypertrophy denote an inflammatory process that is
mechanical in origin and occurs in proximity to the
preinsertional portion of the tendon (Fig. 3.42d,e).
If mild, fluid does not have clinical importance and
reflects irritation due to local overload and work
Muscle and Tendon
At
At
At
∗
a
b
c
At
At
∗
∗
Calcaneus
d
e
Fig. 3.42a-e. Peritendinitis and bursitis. Three different cases. a Peritendinitis of the Achilles tendon in a patient with high-grade
tendinosis and severe posterior ankle pain. Short-axis 12–5 MHz US image over the middle third of the Achilles tendon shows an
abnormal hypoechoic tissue layer (arrows) on the posterior surface of the tendon (At), a finding characteristic of peritendinitis.
b,c Isolated Achilles peritendinitis in a 30-year-old long-distance runner with heel pain of recent onset. b Short-axis 17–5 MHz
US image over the mid-distal Achilles tendon with c sagittal fat-suppressed T2-weighted MR imaging correlation reveals a
crescentic-shaped fluid collection (arrowheads) around the medial aspect of an otherwise normal Achilles tendon (At). Note
the small amount of hypoechoic fluid (asterisk) distending the retrocalcanear bursa. d,e Heel bursitis in a 53-year-old female
tennis-player who suffered from chronic heel pain. d Long-axis and e short-axis 17–5 MHz US images over the distal Achilles tendon (At) demonstrate discrete hypoechoic distention of the retrocalcanear bursa (asterisk) by fluid and hypertrophied
synovium. Some fluid is also seen in the retro-Achilles bursa (arrowheads) and the subcutaneous tissue (arrows) around the
Achilles tendon insertion
stress. Bursitis may cause local discomfort only
when mechanical synovitis is excessive or when the
process is combined with a joint effusion in patients
with primary inflammatory arthropathies such as
rheumatoid arthritis and seronegative spondyloarthropathies, or metabolic disorders such as gout
(Gibbon and Wakefield 1999; Ho et al. 2003).
3.2.5.2
Tenosynovitis
In tendons with a synovial sheath, inflammation
is mostly secondary to repetitive microtrauma, due
to overuse or osseous friction, foreign bodies, or
infection and arthritis. Acute serous tenosynovitis
is diagnosed by identifying an increased amount
of fluid within the tendon sheath (Gooding 1988;
Stephenson 1990). The fluid typically encircles the
tendon forming a “halo” around it: this sign helps
to distinguish the tenosynovial nature of the effusion from other paratendinous cystic lesions, such
as bursae or ganglion cysts, in which fluid is located
eccentrically to the tendon. In subacute or chronic
disease, the effusion is often associated with sheath
thickening (Martinoli et al. 1999). Careful scanning technique is needed to demonstrate small but
significant synovial effusions which, for instance,
can be easily unrecognized if excessive pressure
by the transducer causes collapse of the sheath.
85
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M. P. Zamorani and M. Valle
1
2
T
3
T
bone
a
b
f
3
2
1
s
c
T
s
d
e
Ph
g
Fig. 3.43a–g. Stenosing tenosynovitis. a,b Schematic drawings illustrate the pathomechanism leading to conflict of a type 2
tendon under a thickened retinaculum in an osteofibrous tunnel. a Long-axis and b short-axis views over the affected tendon
demonstrate increased thickness and narrowing of the retinaculum (black) which constrains the underlying tendon (intermediate gray), increased tendon thickness (1) proximal to the retinaculum with sheath fluid distension (light gray), abrupt
narrowing of the tendon size (2) underneath the retinaculum, and mild tendon and sheath abnormalities (3) distal to level of
the retinaculum. c–g Trigger thumb. c–e Short-axis 15–7 MHz US images obtained from c proximal to e distal over the first
metacarpophalangeal joint in a 54-year-old woman with chronic painful extension of the thumb corresponding to the levels
shown in a. Proximal to the A1 pulley, the flexor pollicis longus tendon shows progressive increase of its cross-sectional area
(1); at the level of the sesamoids (s), it sudden decreases in size (2) under the thickened pulley (arrowheads); after exiting the
pulley, the tendon returns to a normal size (3) over the proximal phalanx (Ph). f,g Long-axis 15–7 MHz US images of the flexor
pollicis longus tendon (T) obtained over the thickened A1 pulley (arrowheads) during f flexion and g extension of the distal
phalanx. Dynamic scanning demonstrates the difficult gliding (curved arrow) of the tendon as it passes deep to the thickened
pulley during thumb extension
Depending on its cellular content, the fluid in the
synovial sheath may be anechoic or may contain
subtle echoes in suspension. The entrapment and
chronic conflict of tendons beneath a ligament or a
pulley may cause a stenosing tenosynovitis, i.e., de
Quervain disease, trigger finger (Fig. 3.43a,b). The
involved tendons are diffusely swollen with textural disarrangement and focal or diffuse thickening of the synovial sheath. Simple synovial effusion
is observed in acute cases, whereas chronic cases
present with thickening of the retinacula, which usually represents an indication for operative management (Fig. 3.43c–e). Dynamic US examination with
passive assisted movements may demonstrate the
entrapment of the synovial sheath at the entrance
of the narrowed tunnel (Fig. 3.43f,g).
In infectious tenosynovitis, the effusion tends to
be more echogenic and the overlying subcutaneous
tissue may appear thickened and hyperechoic due to
cellulitis (Brooke Jeffrey et al. 1987; Schechter et
al. 1989). However, it must be emphasized that these
characteristics are too subtle to allow a definitive
diagnosis based on US findings alone. Needle aspiration of fluid, possibly obtained under US guid-
ance, is necessary to confirm the infectious nature
of tenosynovitis as well as to identify the causative bacteria and choose the appropriate antibiotic
therapy. As an exception to this rule, the diagnosis
may be straightforward on US findings when a foreign body is recognized within the synovial sheath
(Fig. 3.44) (Howden 1994). In the setting of infection, color and power Doppler imaging may show
increased flow but is unable to reliably differentiate an infected from a noninfected state (Newman
and Adler 1998). Furthermore, in some instances
there may be no increased blood flow in the sheath,
(Craig et al. 2003). In tuberculous tenosynovitis,
the tendon sheaths appear markedly thickened as a
result of granulomatous changes (Riehl et al. 1997).
Color and power Doppler imaging can detect the
hyperemic state as increased flow signals within the
inflamed sheaths (Breidhal et al. 1998).
In rheumatologic disorders, such as rheumatoid
arthritis and psoriatic arthritis, hypoechoic villous
projections of the synovium (pannus) can develop
inside the effusion and may even fill the synovial
space (Fig. 3.45a-c) (Milosavljevic et al. 2005).
Multiple tendons can be simultaneously involved,
Muscle and Tendon
a
b
c
Fig. 3.44a–c. Infectious tenosynovitis. a Short axis 12-5 MHz gray-scale and b color Doppler US over the right palm in a 35 yearold patient who complained of increasing pain and local inflammatory symptoms one week after a minor penetrating trauma
demonstrate a distended sheath of the flexor tendons (ft) of the long finger by echogenic effusion and hypechoic changes in
the surrounding tissues related to cellulitis (arrows). Note the undefined outer boundaries of the tendon sheath and the intense
superficial hyperemia (arrowheads). m, third metacarpal. c Photograph of the patient’s hand reveals reddish skin (arrow) due
to intense local inflammation.
especially the extensor carpi ulnaris along with
other flexor and extensor digitorum tendons at the
wrist and the posterior tibial tendon. In persistent
synovitis, the biochemical and compressive damage
related to the invading pannus and the mechanical stress caused by chafing of the tendon against
the bone, as in the case of a dorsally subluxated
ulna or Lister tubercle, increases the incidence of
tendon ruptures (Swen et al. 2000). The propensity
for tendon rupture is considered to be independent of the extent of the tenosynovitis and seems to
correlate with aggressive rheumatoid arthritis with
high titers of rheumatoid factor and bone erosions
in an early stage of the disease (Swen et al. 2000). In
these patients with loss of finger function, US can
be used to differentiate the functional impairment
due to joint disease from tendons tears as well as to
detect partial tendon tears that cannot be identified
at physical examination (Swen et al. 2000). Probe
compression can be helpful to differentiate complex
effusion from synovial thickening because fluid may
be squeezed away, in contrast to noncompressible
synovium. Similarly, Doppler imaging has a value
in distinguishing the hypoechoic pannus from the
effusion based on the presence or absence of flow
signals, as well as in differentiating highly vascular,
active pannus from hypovascular fibrous pannus
(Fig. 3.45d) (Newman et al. 1996). Especially in
patients refractory to drug treatment, an early diagnosis of tendon involvement with US is essential to
both plan and improve the outcome after prophylactic tenosynovectomy (Brumfield et al. 1990).
Future possibilities include follow-up of disease
progression and quantification of response to ther-
apy (Newman et al. 1996). Because Doppler imaging
techniques are limited in their ability to detect slowly
flowing blood and small vessels, microbubble-based
US contrast seems promising to increase the US sensitivity to detect hyperemic states in tendons. In the
tibialis posterior, US and MR imaging have similar
accuracy in revealing signs of paratendinopathy,
including peritendinous sheath effusion and hyperemia (Premkumar et al. 2002).
3.2.5.3
Enthesopathy
An enthesis is the point of union between bone and
a tendon, a ligament, an aponeurosis, or a capsule.
Inflammation typically occurs at the enthesis in
seronegative spondyloarthropathy and, to a lesser
extent, in rheumatoid arthritis and gout, leading to
soft-tissue thickening, cortical bone breakage, and
new bone proliferation (Gibbon and Wakefield
1999; Balint et al. 2002). Bursitis and synovitis
often occur in the surrounding tissues. In spondyloarthropathy, the most common sites of involvement are the knee (superior and inferior poles of the
patella, tibial tuberosity), the heel (posterosuperior
and posteroinferior poles of the calcaneus), and the
ischial tuberosity, leading to local pain and stiffness
(Balint et al. 2002). Pain films are normal in early
disease, but they can reveal specific radiographic
features, such as bony erosion, hyperostosis, fragmentation, and crystal deposition as late manifestation of enthesitis (Barozzi et al. 1998; Gnenc et al.
2005). Even better than radiography, US has proved
87
88
M. P. Zamorani and M. Valle
T
T
∗
a
∗
b
∗
T
∗
4
c
d
Fig. 3.45a–d. Hypertrophied tenosynovitis in a 63-year-old woman with long-standing rheumatoid arthritis. a Photograph
demonstrates considerable soft-tissue swelling (arrowheads) over the dorsoulnar aspect of the patient’s wrist. b Long-axis and
c short-axis 17–5 MHz US images over the ventral aspect of the ulnar wrist reveal marked irregular thickening of the synovial
sheath (arrowheads) of the extensor carpi ulnaris tendon (T) with intrasheath fluid (asterisks). d Correlative color Doppler image shows hyperemic synovial walls and intratendinous flow signal, suggestive of active disease. In this particular case, there
was concomitant involvement of the distal radioulnar joint and bone erosions on the ulnar head
to be a sensitive means of detecting bone erosions as
cortical breakages with a step-down contour defect,
and enthesophytes as step-up bony prominences at
the end of the normal bony contour (Barozzi et al.
1998; Balint et al. 2002; Kamel et al. 2003; Gnenc
et al. 2005). However, the advantages of US rely on
its ability to depict associated soft-tissue changes,
including periosseous edema, focal tendon thickening, abnormal tendon echotexture with calcifications, and bursal fluid distension at the site of
tenderness (Lehtinen et al. 1994; Barozzi et al.
1998; Kamel et al. 2003).
3.2.6
Tumors and Tumor-Like Conditions
Primary tumors (i.e., fibroma of the tendon sheath,
clear cell sarcoma) arising from the tendon and its
sheath are exceptional (Gandolfo et al. 2000; Fox
et al. 2003). On the contrary, non-neoplastic spaceoccupying lesions, such as ganglion cysts and the
localized giant cell tumor of the tendon sheath, are
much more common. Although most of these lesions
present as slowly growing painless soft-tissue swellings in the extremities, their mass effect may lead
to compression of adjacent structures and transient
arrest of tendon gliding in a finger, especially if the
mass develops in proximity to retinacula or within
an osteofibrous tunnel (Bertolotto et al. 1996).
3.2.6.1
Intratendinous and Tendon Sheath Ganglia
Ganglion cysts usually arise from para-articular tissues but those originating within a tendon are rare
(Bianchi et al. 1993). The etiology of intratendinous
ganglia is not completely understood: recurrent
injury to the tendon with subsequent cystic degeneration seems to be a possible cause (Kannus and
Jozsa, 1991). The clinical relevance of intratendinous ganglia is based on the fact that they weaken
the structure of tendons and predispose them to
Muscle and Tendon
features of the giant cell tumor reflect the underlying histologic composition and its hemosiderin content (low T2 signal) (Fig. 3.48d–f) (De Beuckeleer
et al. 1997; Kitagawa et al. 2003). Further details on
this tumor are reported in Chapter 11.
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Nerve and Blood Vessels
Nerve and Blood Vessels
Maura Valle and Maria Pia Zamorani
CONTENTS
4.1
4.1.1
4.1.2
4.1.3
4.1.3.1
4.1.3.2
4.1.3.3
4.1.4
4.1.5
4.1.5.1
4.1.6
4.1.6.1
4.1.6.2
4.1.6.3
4.1.6.4
4.1.7
4.1.7.1
4.1.8
4.1.8.1
4.1.8.2
4.1.8.3
4.1.8.4
Nerve 97
Histologic Considerations 97
Normal US Anatomy and
Scanning Technique 98
Anatomic Variants, Inherited and
Developmental Anomalies 101
Fibrolipomatous Hamartoma 101
Charcot-Marie-Tooth Disease 102
Hereditary Neuropathy with Liability to
Pressure Palsies 103
Nerve Instability 104
Compressive Syndromes 104
Nerve Entrapment Syndromes 105
Traumatic Injuries 108
Stretching Injuries 108
Contusion Trauma 108
Penetrating Wounds 109
Postoperative Features 110
Rheumatologic and Infectious Disorders 112
Leprosy 112
Tumors and Tumor-Like Conditions 114
Peripheral Nerve Sheath Tumors 115
Hemangioma and
Non-Hodgkin Lymphoma 119
Intraneural Ganglia 121
Nerve Encasement by
Extrinsic Neoplasms 121
4.2
4.2.1
4.2.2
Blood Vessels 123
Histologic Considerations 123
Normal US Anatomy and
Scanning Technique 125
4.2.3 Musculoskeletal-Related Vascular
Disorders 126
4.2.3.1 Arterial Disorders 127
4.2.3.2 Venous Disorders 129
4.2.4 Vascular Tumors 133
References
133
M. Valle, MD
Staff Radiologist, Reparto di Radiologia, Istituto Scientifico
“Giannina Gaslini”, Largo Gaslini 5, 16148 Genova, Italy
M. P. Zamorani, MD
Unité de Recherche et Dévelopement, Clinique des Grangettes,
7, ch. des Grangettes, 1224 Genève, Switzerland
4.1
Nerve
4.1.1
Histologic Considerations
From the histologic point of view, nerves are round
or flattened cords, with a complex internal structure made of myelinated and unmyelinated nerve
fibers, containing axons and Schwann cells grouped
in fascicles (Fig. 4.1a) (Erickson 1997). Along the
course of the nerve, fibers can traverse from one
fascicle to another and fascicles can split and merge.
Based on the fascicular arrangement, two theories
have been hypothesized to explain the internal
architecture of a nerve: the “cable” and the “plexiform” models (Stewart 2003). The first states that
nerves are cable-like structures, in which fascicles
run separately throughout the entire nerve length
(Fig. 4.1b). The second asserts that fascicles alternate splitting, branching, and rejoining along the
course of the nerve trunk (Fig. 4.1c). In fact, nerves
have both cable and plexiform arrangement of the
fascicles depending on the level of examination. In
their more proximal portion (e.g., brachial plexus),
a plexiform organization of the fascicles predominates. More distally (e.g., median nerve), nerves
present a cable-like structure with high degree of
somatic organization (e.g., sensory and motor fibers
for a specific area of the skin or muscle contained in
the same fascicle) (Stewart 2003). The nerve tissue
is embedded in a series of connective tissue layers.
A closer look at the nerve sheaths demonstrates an
external sheath – the outer epineurium – which surrounds the nerve fascicles. Each fascicle is invested
in turn by a proper connective sheath – the perineurium – which encloses a variable number of nerve
fibers and is responsible for the “blood-nerve” barrier. Then, the individual nerve fibers are invested
by the endoneurium. The connective tissue intervening between the outer nerve sheath and the fascicles is commonly referred to as the interfascicular
97
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M. Valle and M. P. Zamorani
*
*
a
d
b
c
Fig. 4.1a–d. Nerve histology. a Histologic cross-sectional view of the human sural nerve (black arrows) reveals some nerve fascicles (asterisks) of different size containing nerve tissue (violet) with collections of axons, myelin sheaths, and Schwann cells.
Individual fascicles are invested by a thin sheath – the perineurium (arrowheads) – and are separated from each other by a loose
connective tissue envelope – the epineurium (green) – containing small intraneural vessels (white arrows). Specimen stained
using the van Gieson procedure (original magnification ×150). b,c Schematic drawings of a long-axis view through the nerve
trunk illustrate the models of fascicular organization. Arrows indicate the axonal path. b In the “cable model,” the fascicles run
parallel to the nerve axis without axonal exchange. c In the “plexiform model,” fascicles split and rejoin in various combinations with axons intermingling from one to another. d Schematic drawing of a cross-sectional view of the monofascicular (1),
oligofascicular (2), and polyfascicular (3) nerve models. In complex motor and sensory nerves (3), fascicles (asterisks) are of
different size and may be grouped in function-related areas within the nerve. This drawing (3) recalls the structure of the sciatic
nerve, in which the nerves fibers for the tibial nerve (light gray) and for the peroneal nerve (dark gray) remain grouped tightly
throughout the course of the nerve, even proximally
epineurium (internal epineurium), as opposed to the
outer epineurium which surrounds the entire nerve
trunk. Generally speaking, the amount of connective
tissue of the epineurium is more abundant in large
multifascicular nerves and in regions in which the
nerve is mobile across joints (Delfiner 1996). This
thickening of the connective tissue seems to provide
more cushioning for the nerve and, therefore, more
resistance to compression injury (Delfiner 1996).
Externally, the outer (external) epineurium is continuous with the mesoneurium, which is made up
of loose areolar tissue. This latter structure is credited with not only supplying the framework for the
blood supply entering the nerve, but also making
the excursion of the nerve in its bed easier without
traction on its blood supply during joint motion
(George and Smith 1996).
Nerves have a prominent vascular supply to ensure
their continuous supply of local energy required for
impulse transmission and axonal transport. The
vascular supply is formed by an interconnected
system of perineural vessels that course longitudinally in the external epineurium and branch among
the fascicles (endoneural vessels).
4.1.2
Normal US Anatomy and Scanning Technique
Thanks to the latest generation of high-frequency
“small parts” transducers and compound technology, US has become a well-accepted and widespread imaging modality for evaluation of peripheral nerves. The improved performance of these
transducers has made it possible to recognize
subtle anatomic details at least equal to or even
smaller than those depicted with surface-coil MR
imaging and to depict a wide range of pathologic
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M. Valle and M. P. Zamorani
a
b
Fig. 4.3a,b. Normal nerve echotexture. a Short-axis and b long-axis 15–7 MHz US images over the median nerve (open arrows)
at the mid-forearm. In a, the nerve fascicles (white arrow) are depicted as well-circumscribed individual structures of different
size separated by echogenic epineurium. In this segment, 11 fascicles are distinguished in the cross-sectional area of the median nerve. In b, the nerve fascicles appear as elongated hypoechoic bands (white arrows) that run parallel to each other. The
internal epineurium (white arrowheads) separates them more clearly, while the external epineurium (open arrowheads) helps
to define the outer boundaries of the nerve
color and power Doppler systems are, for the most
part, unable to recognize the weak and small blood
flow signals from the perineural plexus and the
intraneural branches. Generally speaking, nerves
are compressible and alter their shape depending
on the volume of the anatomic spaces within which
they run as well as on the bulk and conformation
of the perineural structures (Fig. 4.4a,b). Even
with slight pressure applied with the probe, they
may be seen sliding over the surface of an artery
or a muscle. As a general rule, each individual fascicle in a nerve runs independently of the others.
Across synovial joints, they pass through narrow
anatomic passageways – the osteofibrous tunnels
– that redirect their course. The floor of these tunnels consists of bone, whereas the roof is made
of focal thickenings of the fascia – the retinacula
– that prevent dislocation and traumatic damage of
the structures contained in the tunnel during joint
activity (Martinoli et al. 2000b). When nerves
cross tight passages, such as neural foramina and
osteofibrous tunnels, subtle echotextural changes
can be seen, with a more homogeneous hypoechoic appearance caused by tighter packing of the
fascicles and local reduction in the volume of the
epineurium (Sheppard et al. 1998).
A careful scanning technique based on the precise knowledge of their position and analysis of their
anatomic relationships with surrounding structures
is essential for recognizing peripheral nerves with
US. Unlike other structures of the musculoskeletal
system, nerves do not show anisotropic properties.
Therefore, appropriate probe orientation during
scanning is not needed to image them; however, systematic scanning in the short-axis plane is preferred
for following the nerves contiguously throughout
the limbs (Martinoli et al. 1999). Long-axis scans
are less effective for this purpose because the elongated fascicles may be easily confused with echoes
from muscles and tendons coursing along the same
plane. Once detected, the nerve is kept in the center
of the US image in its short axis and then followed
proximally and distally, shifting the transducer up
or down according to the nerve’s course. With this
technique – which we can call the “lift technique”
– the examiner is able to explore long segments of
a nerve in a few seconds throughout the limbs and
extremities (Fig. 4.4c). If intrinsic or extrinsic nerve
abnormalities are encountered during scanning, the
US examination is then appropriately focused on
the region of interest using oblique and longitudinal US scanning planes. Although all main nerves
can be readily displayed in the extremities due to
their superficial position and absence of intervening
bone, depiction of the peripheral nervous system is
not possible everywhere with US. In fact, most cranial nerves – except for the vagus – and the spinal
accessory nerve (Giovagnorio and Martinoli,
2001; Bodner et al. 2002a), the nerve roots exiting
the dorsal, lumbar and sacral spine, the sympathetic
chains, and the splanchnic nerves in the abdomen
cannot be visualized due to their course being to
deep or interposition of bony structures. In addition, the perineural structures greatly influence
nerve detection in the limbs and extremities. When
nerves course deeply, as in obese patients, their
evaluation can be difficult. As a general rule, nerves
of the lower extremity run deeper than those of the
upper extremity and are more difficult to visualize. Nerves coursing among hypoechoic muscles are
Nerve and Blood Vessels
a
b
c
Fig. 4.4a–c. Response to compression and nerve scanning technique. a,b Schematic drawings of the cross-sectional view of a
nerve lying over a stiff surface (bone) a at rest and b during external compression (arrow). Due to the flexibility of the epineurial
sheath, the nerve flattens, whereas the fascicles – which are noncompressible structures – redistribute according to the nerve
shape changes. c Photograph shows the standard technique for examining nerves in the limbs. The short axis of the median
nerve at the wrist is centered in the field of view of the US image. Then, the transducer is swept upward (dashed arrow) along
the course of the nerve in the forearm. This technique, which we can call the “lift technique,” allow a simple and reliable evaluation of long nerve segments in a single sweep, excluding possible intrinsic and extrinsic abnormalities along the nerve path.
The ability of US to follow the entire course of nerves in the limbs so quickly is a major advantage over MR imaging
detected easier than those surrounded by hyperechoic fat. Similarly, a nerve of a young physically
active subject is better depicted than the same nerve
examined in a subject with atrophic muscles.
4.1.3
Anatomic Variants, Inherited and
Developmental Anomalies
Given the characteristic US appearance of normal
nerves, some anatomic variants can be recognized
with this technique. Among these, the proximal bifurcation of the median nerve at wrist has
been extensively reported in the literature (see
Chapter 10) (Propeck et al. 2000; Iannicelli et al.
2000; Gassner et al. 2002). Similarly, some inherited and developmental anomalies of the peripheral
nervous system, such as the fusiform enlargement
of the median nerve by fibrofatty tissue (so-called
fibrolipomatous hamartoma), the hypertrophy of nerves in Charcot-Marie-Tooth syndrome
(Martinoli et al. 2002), and the focal enlargement
of nerves in hereditary neuropathy with liability to
pressure palsies (Beekman and Visser 2002) can be
recognized with US. In these disorders, US findings
may contribute to the understanding of pathophysiology by noninvasively revealing some important
morphologic information. Further work is, however,
required to fully analyze the impact and reliability
of US in this field.
4.1.3.1
Fibrolipomatous Hamartoma
Fibrolipomatous hamartoma is a developmental
tumor-like nerve disorder related to the hypertrophy of mature fat and fibroblasts in the epineurium
that often presents during early childhood. This
condition – which is also referred to as neural fibrolipoma, perineural lipoma, fatty infiltration of the
nerve, lipofibroma, or neural lipoma – has a definite
predilection for the median nerve and its branches,
with lower extremity involvement (plantar nerve,
sciatic nerve) reported as being rare (Marom and
Helms 1999; Wong et al. 2006). Fibrolipomatous
hamartoma may be associated with local gigantism
of an extremity, usually the hand or foot, related to
bony overgrowth, fat proliferation in the soft tissues, and nerve-territory-oriented macrodactyly,
characteristic of the condition known as macrodystrophia lipomatosa (Amadio et al. 1988; Murphey
et al. 1999). The US appearance of fibrolipomatous
hamartoma is pathognomonic of this entity, reflecting the morphology of the lesion. US demonstrates a
101
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Nerve and Blood Vessels
1cm
a
c
*
va
v
1cm
b
d
Fig. 4.6a–d. Charcot-Marie-Tooth disease in a 37-year-old woman with type 1A disease. a Histologic slice of a fascicle of the sural
nerve demonstrates the abnormal “onion bulb” appearance (arrow) of the Schwann cells, a peculiar finding of Charcot-MarieTooth disease. Original magnification ×800. b Transverse T1-weighted MR image of the posterior ankle reveals an enlarged tibial
nerve (arrows) characterized by swollen fascicles. The nerve is much larger than normal. Note the atrophic changes in the flexor
hallucis longus muscle (asterisk) and the adjacent posterior tibial artery (a) and veins (v). c Short-axis 12–5MHz US image over
the middle forearm reveals hypertrophy of the median nerve (open arrows) and its fascicles. d Corresponding 12–5 MHz US
image of the median nerve obtained for comparison in a healthy woman at the same magnification shown in c demonstrates a
smaller median nerve (open arrows) and fascicles. Note the equivalent size of the flexor carpi radialis (arrowheads) and palmaris
longus (white arrow) tendons in the two images. The magnification scale is indicated on the right
constantly changing (because not all the causative
genes have yet been described), the most common
forms include the autosomal dominant types 1A and
2 that are related to DNA duplication of a region on
chromosome 17 which codes for a peripheral myelin
protein, and the X-linked type that is related to a
mutation in the gene which codes for connexin 32,
which is a gap-junction protein (Schenone and
Mancardi 1999). The degree of electrophysiologic
alterations varies widely among patients with different forms of the disease, especially in the type 1A,
as a result of phenotypic differences and the action
of stochastic factors or environmental modulation
of disease severity (Schenone and Mancardi
1999). Nerves appear larger than normal but retain
a normal fascicular echotexture (Heinemeyer and
Reimers 1999; Martinoli et al. 2002). In considering the main genetic types of Charcot-Marie-Tooth
disease, such as the autosomal dominant types 1A
and 2, and the X-linked type, patients with type 1A
have markedly larger fascicles than patients with
the other disease subtypes. In these patients, the
diameter of the fascicles and the resulting nerve area
are more than twice those seen in healthy subjects
and in type 2 and the X-linked type (Fig. 4.6c,d)
(Martinoli et al. 2002). There is no correlation
between the maximum fascicular size of the nerve
and electrophysiologic features, such as distal latencies, velocities, and amplitude (Martinoli et al.
2002). In this specific clinical setting, US can be
used to help the neurologist identify unrecognized
disease in patients with nonspecific symptoms, to
differentiate the 1A genetic subtype, and to provide a
useful screening tool for a first selection of the individuals in an affected kindred who are to undergo
genetic assessments.
4.1.3.3
Hereditary Neuropathy with Liability to Pressure
Palsies
Hereditary neuropathy with liability to pressure
palsies, also known as tomaculous neuropathy, is
104
M. Valle and M. P. Zamorani
an autosomal dominant inherited disorder characterized by a tendency to develop focal neuropathies
after trivial trauma that is related to a deletion in
chromosome 17p11.2-12 producing reduced expression of peripheral myelin protein 22 (Verhagen
et al. 1993). Histopathologically, a sausage-shaped
myelin sheath swelling, the so-called tomacula, is
responsible for multifocal nerve enlargement. Electrophysiologic studies demonstrate one or more
entrapment neuropathies on a background of motor
and sensory polyneuropathy. The more frequently
involved nerves are: the peroneal nerve at the fibular tunnel, the ulnar nerve at the cubital tunnel, the
radial nerve at the spiral groove, and the median
nerve at the carpal tunnel (Verhagen et al. 1993;
Beekman and Visser 2002). US is able to recognize
focal nerve enlargement not only at the osteofibrous
tunnels that are typically involved, but also along the
course of nerves throughout the limbs (Fig. 4.7). It is
conceivable that the “sausage-shaped” myelin swellings (tomacula) found at teased nerve fiber studies
in patients with this disorder are responsible for
nerve enlargement (Beekman and Visser 2002).
4.1.4
Nerve Instability
Dynamic US of the elbow can be used to help demonstrate abnormal dislocation of the ulnar nerve,
with or without snapping triceps syndrome. This
finding typically occurs in the cubital tunnel, an
osteofibrous tunnel formed by a groove between the
olecranon and the medial epicondyle and bridged by
the Osborn retinaculum. As described in Chapter
8, dynamic scanning during full elbow flexion can
allow continual depiction of the intermittent dislo-
a
b
cation of the ulnar nerve over the medial epicondyle
if the retinaculum is loose or absent (Jacobson et al.
2001). Dislocation of the medial edge of the triceps
can also occur in combination with dislocation of
the ulnar nerve (Jacobson et al. 2001). In this syndrome, the ulnar nerve dislocation is secondary to
the snapping triceps and dynamic scanning demonstrates the medial head of the triceps and the ulnar
nerve remaining in close continuity as they dislocate
over the medial epicondyle (see Chapter 8).
4.1.5
Compressive Syndromes
From a general pathophysiologic point of view,
nerve compression can occur acutely or develop
chronically. Short periods of constriction result in
slowing and failure of conduction across the constriction point, whereas the nerve portion distal to
the region that was compressed retains a normal
function. The conduction abnormalities, which are
generally referred to by the term “neuroapraxia,”
tend to resolve but there may be a prolonged latency
until full recovery. This type of injury typically
occurs in the radial nerve at the spiral groove of
the humerus, the so-called “Saturday night radial
palsy”, and in the peroneal nerve around the fibular
head and neck, the so-called “crossed leg peroneal
palsy”. If local compression is prolonged, ischemia
induced by direct severe compression, mechanical distortion of the nerve architecture, may cause
more significant damage in the myelin sheath and
axonal degeneration (Wallerian degeneration) of
the nerve fibers and persistent nerve deficit due to
disruption of the axoplasm after the compression
has been relieved (Delfiner 1996). In chronic nerve
Fig. 4.7a,b. Hereditary neuropathy with liability to pressure palsies in a 42-year-old man
with mild median and ulnar neuropathy. a
Long-axis 12–5 MHz US image of the ulnar
nerve (arrowheads) at the middle forearm
with b schematic drawing correlation reveals
mild fusiform thickening (arrows) of the nerve
out of osteofibrous tunnels
106
M. Valle and M. P. Zamorani
close proximity to the compression level, where the
nerve abruptly flattens. Given these features, US is an
accurate means of identifying the level of compression as located just ahead of the swollen nerve portion. Although nerve flattening should be regarded
as the main sign of nerve compression, quantitative
analysis of nerve thickening by means of the ellipse
formula [(maximum AP diameter) × (maximum LL
diameter) × (π/4)] has proved to be the most consistent criterion for the diagnosis at various entrapment sites (Chiou et al. 1998; Duncan et al. 1999;
Bargfrede et al. 1999). As an ancillary finding,
dynamic scanning may show a reduced mobility of
the nerve over the mass or beneath the retinaculum,
but this latter sign is too subjective and hard to quantify with US (Nakamichi and Tachibana 1995). At
least at the carpal tunnel level, the cross-sectional
area of the median nerve has also been regarded as
an index for selecting patients with severe disease for
which surgical decompression is indicated (Lee et al.
1999). It is conceivable that loss of axons may be associated with nerve enlargement as an expression of an
increased amount of endoneural edema (Beekman
et al. 2004b). In entrapment neuropathies, the nerve
echotexture may become uniformly hypoechoic with
loss of the fascicular pattern at the level of the com-
pression site and proximal to it (Fig. 4.9). In general,
the hypoechoic changes occur gradually and become
more severe as the nerve nears the site of compression
(Martinoli et al. 2000b). They derive from swelling
of the individual fascicles and decreased echogenicity of the epineurium. The outer lining of the nerve,
which is normally undefined and part of a continuum
with the epineurium and surrounding fat, becomes
sharp and well delineated. Depiction of such changes
may increase confidence in the diagnosis and in
determining the exact level of the lesion. In cases
of entrapment by scar tissue, diagnostic difficulties
may arise in distinguishing echotextural changes
related to the compressed nerve from the scar itself,
because of a similar hypoechoic appearance. Then,
an enhanced depiction of intraneural blood flow signals can be appreciated with color and power Doppler
techniques as a sign of local disturbances in the nerve
microvasculature that occur in a compressive context
(Martinoli et al. 2000b). The hypervascular pattern
is more clearly appreciated in swollen hypoechoic
nerves of patients with chronic, longstanding disease. Intranervous flow signals are made up of many
vessel pedicles that enter the nerve from the superficial epineurium to run perpendicular to the fascicles
(Fig. 4.10) (Martinoli et al. 1999, 2000b).
a
c
b
d
Fig. 4.9a–d. Entrapment neuropathies: echotextural changes. a,b Short-axis 17–5 MHz US images of the right median nerve
obtained a at the distal radius and b just ahead of the compression point in a patient with longstanding carpal tunnel syndrome. As the nerve (arrows) approaches the site of compression, increasing hypoechoic changes are detected due to crowding
of edematous fascicles and reduced echogenicity of the epineurium. This leads to a complete loss of the fascicular echotexture.
c,d Schematic drawing correlation
Nerve and Blood Vessels
1
3
b
*
*
*
2
*
a
c
d
Fig. 4.10a–d. Entrapment neuropathies: microvascular changes. a Schematic drawing illustrates the nerve vascular system,
made up of perineural vessels (1) coursing alongside the nerve. These vessels give off intraneural branches that pierce the
outer epineurium (2) and distribute longitudinally (3) among the fascicles. b,c Long-axis 12–5 MHz color Doppler US images
of the median nerve (asterisks) in a 56-year-old patient with carpal tunnel syndrome demonstrate subtle flow signals from the
longitudinal perineural plexus (arrows) and a series of intranervous branches (arrowheads) running among the fascicles. d
Corresponding transverse Gd-enhanced fat-suppressed T1-weighted MR image obtained just deep to the flexor retinaculum
(arrowheads) reveals marked uptake of contrast material in the median nerve (arrow)
Based on the US assessment, nerve entrapment
syndromes can be divided into three main classes.
The first includes large nerves (i.e., the median, the
ulnar, the radial, the sciatic, the tibial, etc.) which
are easily depicted with US at the site of compression. In these cases, US evaluation can be effectively
performed with conventional (mid-range) equipment and the diagnosis is based on pattern recognition analysis and quantitative measurements.
The second includes small nerves (i.e., the posterior and anterior interosseous, the musculocutaneous, the peroneal, the sural, the plantars, etc.) the
depiction of which requires high-end equipment
and high-performance transducers. In these cases,
quantitative measurements are usually not applied.
The third class includes nerves which are not detectable with US because they are either too small (i.e.,
most part of the saphenous, etc.), or have too deep
a course and are hidden by intervening bone (i.e.,
the suprascapular nerve, the intrapelvic course
of the sciatic and the femoral nerve, etc.). In these
cases, the US diagnosis is based only on the indirect evaluation of the innervated muscles to identify
denervation signs (see Chapter 3). In the first two
classes, there are many sites of nerve entrapment
that are amenable to US examination in the upper
and lower limb, and whatever the site and the nerve
involved, the US signs described previously are virtually pathognomonic of compressive neuropathy.
They include: the spinoglenoid-supraspinous notch
area in the posterior shoulder for the suprascapular nerve (see Chapter 6) (Martinoli et al. 2003);
the quadrilateral space for the axillary nerve (see
Chapter 6) (Martinoli et al. 2003; the spiral groove
of the humerus for the radial nerve (see Chapter 7)
(Peer et al. 2001; Bodner et al. 1999, 2001; RosseyMarec et al. 2004; Martinoli et al. 2004); the supinator area at the elbow for the posterior interosseous
nerve (see Chapter 8) (Bodner et al. 2002b; Chien
et al. 2003; Martinoli et al. 2004) and the wrist
for the superficial branch of the radial nerve (see
Chapter 10); the cubital and Guyon tunnels for the
ulnar nerve (see Chapters 8, 10) (Chiou et al. 1998;
Puig et al. 1999; Okamoto et al. 2000; Martinoli
et al. 2000b, 2004; Nakamichi et al. 2000; Bianchi
et al. 2004; Beekman et al. 2004a; Beekman and
Visser 2004); the middle forearm for the anterior
interosseous nerve (see Chapter 9) (Hide et al. 1999)
and the carpal tunnel for the median nerve (see
Chapter 10) (Altinok et al. 2004; Buchberger et
al. 1991, 1992; Nakamichi and Tachibana 1995;
Bertolotto et al. 1996; Lee et al. 1999; Chen et al.
107
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M. Valle and M. P. Zamorani
1997; Duncan et al. 1999; Martinoli et al. 2002b;
Kele et al. 2003; Bianchi et al. 2004; El Miedany
et al. 2004; Yesildag et al. 2004; Wilson 2004;
Wong et al. 2004; Kotevoglu and GülbahceSaglam 2005; Koyuncuoglu et al. 2005; Ziswiler
et al. 2005); the posterior hip or proximal thigh
for the sciatic nerve (see Chapter 12) (Graif et al.
1991); the fibular head and neck for the common
peroneal nerve (see Chapter 14) (Martinoli et al.
2000b); the tarsal tunnel for the tibial nerve (see
Chapter 16) (Martinoli et al. 2000b) and the intermetatarsal spaces for the interdigital nerves (see
Chapter 17) (Redd et al. 1989; Read et al. 1999;
Sobiesk et al. 1997; Quinn et al. 2001). A detailed
overview of these syndromes is reported later in the
chapters on the individual anatomic sites.
With respect to the electrophysiologic findings, a
positive correlation between the nerve cross-sectional
area and the severity of electromyographic findings
has been found, whereas only a modest negative correlation seems to exist between electrodiagnostic
parameters, such as motor velocity, CMAP amplitude, distal SNAP, and the nerve cross-sectional area
(Kele et al. 2003; Beekman et al. 2004; El Miedany
et al. 2004; Ziswiler et al. 2005). Generally speaking,
US can complement nerve conduction studies in the
evaluation of nerve entrapment syndromes. It can
be informative in patients with absent motor or sensory responses, when it is difficult to localize the site
of compression. A positive US study can reduce the
uncertainty of nerve conduction studies and, therefore, reduces the need for further exclusionary studies. In addition, US can identify abnormal findings
in the nerve surroundings, such as synovitis, spaceoccupying masses, or anomalous muscles, providing
important information in the preoperative setting.
After surgical decompression, the US appearance
and mobility of the affected nerves may improve, and
it is possible to visualize the altered morphology of the
osteofibrous tunnel after release of the retinaculum
(Martinoli et al. 2000b; El-Karabaty et al. 2005).
4.1.6
Traumatic Injuries
Traumatic nerve injuries derive from traction, contusion, and penetrating trauma. Here we attempt
a brief overview of nerve trauma according to the
different mechanisms involved. In many cases,
however, multiple mechanisms may coexist and,
therefore, an exact differentiation among them is
not always feasible in clinical practice.
4.1.6.1
Stretching Injuries
Nerve stretching injuries typically occur as a result of
repetitive sprain or strain lesions, as well as with overuse. A characteristic injury is the avulsion of the nerve
roots that occurs in brachial plexus trauma during
motor vehicle accidents (see Chapter 6) (Shafighi
et al. 2003; Graif et al. 2004). Another typical site
of nerve traction is the popliteal fossa, where the
peroneal nerve may be stretched during high-grade
sprains, knee dislocation or fractures (see Chapter 12)
(Gruber et al. 2005). In complete nerve lacerations,
US reveals disruption of the fascicles with retraction
and a wavy course of the nerve ends (Shafighi et
al. 2003; Graif et al. 2004; Gruber et al. 2005). The
outer nerve sheath may be intact. If traction injury
causes partial nerve tear, a spindle neuroma (traction
neuroma) can develop as an irregular swelling of hypoechoic tissue along the course of the severed nerve
without evidence of nerve discontinuity (Fig. 4.11; see
also Chapters 6, 12) (Bodner et al. 2001; Graif et al.
2004). In mild cases, the neuroma may involve only
one or a few fascicles while the cross-sectional area of
the nerve appears fairly normal or slightly enlarged.
4.1.6.2
Contusion Trauma
Contusion trauma most often occurs where nerves run
closely apposed to bony surfaces at sites of low mobility and, are therefore, more vulnerable to external
injuries. In most cases, such trauma is self-resolving
and does not cause morphologic changes detectable
with US (Fig. 4.12). Repeated minor contusion trauma
is usually required to cause abnormalities within the
nerve substance that can be detected with US. A typical contusion trauma is that involving the radial nerve
where it pierces the lateral intermuscular septum, or
the deep peroneal nerve against the midfoot bones
in soccer players who receive repeated blows over
the dorsum of the foot (see Chapter 17) (Schon 1994;
Quinn et al. 2001). These lesions lead to development
of a segmental fusiform thickening of the nerve at the
site of trauma. A peculiar kind of contusion trauma
is that involving unstable ulnar nerves at the cubital
tunnel in patients with absence of the Osborne retinaculum. In predisposed subjects, the repeated friction of the nerve against the epicondyle during elbow
flexion may cause chronic damage and functional
deficit, so-called “friction neuritis”. In these cases,
the nerve appears swollen and hypoechoic as a result
109
Nerve and Blood Vessels
sm/sp
sa
a
b
Fig. 4.11a,b. Stretching injury (burner/stinger syndrome) of the brachial plexus nerves in a 25-year-old rugby player with persistent tingling radiating from the left shoulder to the hand and progressive weakness of the limb muscles after a significant
contact injury. a Short-axis and b long-axis 12–5 MHz US images over the interscalene area demonstrate segmental thickening
of the C5 (open arrows), C6 (white arrows), and C7 (arrowheads) components of the plexus (upper and middle trunks), reflecting fusiform neuromas related to stretching trauma. sa, scalenus anterior; sm/sp, scalenus medius/scalenus posterior muscles.
In the burner/stinger syndrome, MR imaging of the cervical spine should always be performed to rule out nerve damage inside
the spinal canal as well as herniated disks, ligament injuries, facet injuries, and undisplaced fractures
a
b
c
d
Fig. 4.12a–d. Nerve contusion trauma. Peroneal neuropathy in a 15-year-old boy with onset of foot-drop after receiving a blow
on the lateral knee. a Lateral plain film demonstrates an exostosis (arrow) at the fibular metaphysis. b Transverse 12–5 MHz US
image reveals impingement of the peroneal nerve (arrow) against the cartilaginous component (arrowheads) of the exostosis.
The nerve is swollen and hypoechoic. c,d Correlative transverse fat-suppressed GRE T2* MR images demonstrate a hyperintense
nerve (arrow) crossing the exostosis (arrowhead). Note the T2-hyerintense cap of the exostosis
of fibrotic changes and shows a thickened external
epineurium (see Chapter 8) (Jacobson et al. 2001).
4.1.6.3
Penetrating Wounds
In penetrating wounds (glass fragments are often
involved!), there may be a partial or complete inter-
ruption of the nerve fascicles. Regenerating Schwann
cells and axons grow randomly at the lesion site in
an attempt to restore the continuity of the nerve.
Generally, the gap between the separated fascicles
is wide, and new axonal sprouts develop in many
directions. A hypoechoic fibrous mass is the result
of such a disorganized repair process. In complete tears, stump neuromas (terminal neuromas)
appear as small hypoechoic masses in continuity
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M. Valle and M. P. Zamorani
with the opposite edges of the severed nerve (see
Chapters 9, 10) (Provost et al. 1997; Graif et al.
1991; Simonetti et al. 1999). Usually, their size is
slightly larger than the axial diameter of the nerve.
Most have well-defined margins; however, when they
are attached to the surrounding tissues by adhesions and encasing scar tissue, their borders may be
irregular or poorly defined (Bodner et al. 2001). US
depiction of terminal neuromas may map the location of the nerve ends, which may be displaced and
retracted from the site of the injury (Fig. 4.13a–c).
When the nerve ends are close together, the bulk
of neuroma may encase them mimicking a partial
tear. In some way, this seems to suggest that US is
unable to quantify the grade of nerve damage within
a spindle neuroma. When the nerve is partially torn,
the hypoechoic neuroma may encase resected and
preserved fascicles giving rise to a homogeneous
fusiform swelling of the nerve or can be seen arising specifically from the resected fascicles, while the
unaffected fascicles can be appreciated continuing
their course alongside the fibrous mass (Fig. 4.14).
In this latter instance, US is able to estimate the
amount (percentage) of fascicles involved in the neuroma (Fig. 4.14d). Overall, US may help the clinical
b
1
4.1.6.4
Postoperative Features
In patients with partial nerve tear, a delicate procedure of internal neurolysis of the nerve and its
sheath is mainly used for either repairing the interrupted nerve fascicles or removing intraneural scar
tissue. With this procedure, the main risk consists of
inadvertent damage to preserved fascicles and formation of a new postoperative scar close to the nerve
surface. With complete transection of the nerve, a
more complex surgical procedure is required. The
appropriate selection of an adequate reconstruction
technique depends on the length of the gap intervening between the nerve ends after removal of irreversibly damaged tissue and terminal neuromas. Where
the gap is short, an “end-to-end” anastomosis is preferred given that substantial tension on the sutured
2
1
a
examination and nerve conduction studies to provide information about the condition of the injured
nerve, and especially in deciding whether early surgical treatment is required. This is particularly true
for minor nerve lesions without axonal damage.
2
1
c
2
2
1
d
e
Fig. 4.13a–e. Complete nerve tear in a 12-year-old girl with loss of function of the median nerve after receiving a penetrating
injury to the arm by a glass fragment. In the acute setting, the patient was operated on for laceration of the brachial artery. a,b
Long-axis 15-7 MHz US images at the level of injury demonstrate discontinuity of the median nerve. Note the proximal and
distal stumps (arrowheads) of the severed nerve ending in a hypoechoic terminal neuroma (1, 2). c Gross surgical view shows
discrete retraction (4 cm gap) of the nerve ends. d After reconstructive surgery, a long-axis 12–5 MHz US image demonstrates
the sural nerve graft (curved arrow) interposed between the nerve ends (arrowheads). A fusiform hypoechoic thickening is
observed at the proximal (1) and distal (2) site of anastomosis: it should be regarded as a normal finding. A split-screen image
was used, with the two screens aligned for an extended field of view. e Surgical correlation
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M. Valle and M. P. Zamorani
lections. A mild and fusiform increase in the nerve
size at the sutures level is a normal finding. In contrast, marked irregular bulging of hypoechoic tissue
at the anastomosis, possibly involving one side of
the nerve, should be regarded as a pathologic sign,
indicating inadequate fusion of the nerve edges and
postsurgical neuroma formation (Graif et al. 1991;
Peer et al. 2001). Excessive tension on the nerve
edges and infection are possible causes of defective
anastomosis. In this clinical setting, US may compensate for the limitations of electrodiagnosis and
clinical examination by yielding reliable information on the size, extent, and localization of postsurgical scarring and neuromas with respect to further
surgical intervention (Peer et al. 2003).
In addition to primary (trauma-related, neurolysis-related) causes, scar formation may occur
following surgery that has not been primarily
directed to the nerve (i.e., fracture repair, vascular
surgery, etc.). Scar tissue may encase the nerve as a
whole or may lie adherent to its surface (Fig. 4.16).
The nerve appears flattened and indistinguishable
within the scar or may be distorted at its periphery with reactive focal swelling related to edema
and venous congestion (Fig. 4.16c,h). Under these
circumstances, nerve scarring may lead to persistent pain and delayed recovery of nerve function
because of constant traction on the nerve and limited capability for longitudinal translation during
joint movements. In the postoperative setting, US
findings of incidental iatrogenic injuries to peripheral nerves have been reported in the radial, femoral, accessory, and sciatic nerves (Graif et al. 1991;
Peer et al. 2001; Bodner et al. 2002a; Gruber et
al. 2003).
4.1.7
Rheumatologic and Infectious Disorders
In several rheumatologic disorders, such as rheumatoid arthritis, polyarteritis nodosa, Wegener’s granulomatosis, and Churg-Strauss and Sjögren syndromes, one of the clinical landmarks of vasculitis
is the appearance of neurologic findings (Lanzillo
et al. 1998; Rosenbaum 2001). From the pathophysiologic point of view, vasculitis-related neuropathy
affects large nerve trunks producing a multifocal
degeneration of fibers as a result of necrotizing angiopathy of small nerve arteries, so-called multiple
mononeuropathy (Said and Lacroix 2005). In these
patients, the neuropathy does not correlate with disease parameters, such as disease activity, rheuma-
toid factor, and functional and radiologic scores,
and there is sequential involvement of individual
nerves both in time and anatomically (Nadkar et
al. 2001). Nerve conduction velocities are usually not
markedly reduced from normal, provided that the
compound nerve or muscle action potential is not
severely reduced in amplitude (Sivri and GulerUysal 1998). Although multiple mononeuropathy is
the most common manifestation, nerve entrapment
syndromes may also occur at sites where nerves pass
in close proximity to either a synovial joint (i.e.,
cubital tunnel, tarsal tunnel, Guyon tunnel) or one or
more synovial-sheathed tendons (i.e., flexor tendons
at the carpal tunnel, flexor hallucis longus at the
tarsal tunnel) or para-articular bursae (i.e., iliopsoas
bursa at the hip). Because the clinical evaluation of
nerves is often limited in these patients by simultaneous symptoms resulting from joint involvement,
US imaging can contribute to distinguishing entrapment neuropathies related to derangement of joints,
effusions, and synovial pannus from non-entrapment neuropathy. This is based on the fact that multiple mononeuropathy does not lead to an altered
morphology of the affected nerve, whereas entrapment neuropathies do.
4.1.7.1
Leprosy
Leprosy (Hansen disease) is a chronic infectious
disease caused by Mycobacterium leprae, which, in
its many and various clinical forms, involves the
skin and nerves (Fig. 4.17a). Although in the Western world leprosy is almost only seen in immigrants,
it is endemic in developing countries (tropics and
subtropics) with 12 million people affected; it therefore represents the most diffuse neuropathy in the
world. Leprosy is probably spread by droplet infection, but prolonged household contact is needed and
most people are not susceptible to the disease. From
the clinical point of view, leprosy can be grouped
into two polar forms – tuberculoid and lepromatous – between which borderline forms show an
intermediate spectrum of phenotypes (Ridley and
Jopling 1966). In tuberculoid leprosy, there is an
intense immune response: aggressive infiltration of
epithelioid and lymphoid cells into the nerve causes
thickening of the epineurium and perineurium and
destruction of fascicles. In the lepromatous type,
the immune response is indolent and active proliferation of bacilli occurs: this form shows better
preservation of the nerve architecture. Transition
Nerve and Blood Vessels
humerus
a
humerus
b
d
c
e
f
g
h
Fig. 4.16a–h. Postoperative encasement of nerves by scar tissue. Two different cases. a,b Radial nerve buried in a fibrous callus
after repair of humeral shaft fracture. a Long-axis and b short-axis 17–5 MHz US images show focal encasement of the radial
nerve (open arrowheads) by an ill-defined hypoechoic mass (white arrowheads) developing over the fracture site (arrow) reflecting the formation of fibrous callus. The nerve’s fascicular echotexture is retained within the callus. The patient underwent
a second surgical look to free the nerve from the callus. c–h Peroneal nerve encased in a scar after surgical stripping of the
saphenous vein. c Photograph shows the surgical access. d Long-axis 12–5 MHz US image of the peroneal nerve (arrows) with
e schematic drawing correlation reveals distortion and pinching of the nerve fascicles (open arrowheads) by hypoechoic scar
tissue (white arrowheads). f–h Short-axis 12–5 MHz US images obtained from f proximal to h distal show the normal peroneal
nerve (open arrow) which becomes indistinguishable (open arrowheads) within the scar (white arrowheads) and then as it
(white arrow) exits the scar to return to a normal appearance
toward a higher resistance form of leprosy may
produce episodes of acute neuritis, such as the socalled “reversal reaction” and “erythema nodosum
leprosum”. During these phases, a nerve segment
may become intensely painful and tender. As the
disease progresses, subsequent episodes of neuritis
add to the deficit until the affected nerve may be
completely destroyed. Sensory abnormalities usu-
ally precede paralysis. The initial symptom of nerve
involvement is sensory loss, which increases the frequency of minor trauma, leading to infections and
eventually to mutilating injuries, and blindness.
The preferred sites of nerve swelling in leprosy are
similar to those of entrapment neuropathies (i.e.,
the cubital tunnel for the ulnar nerve, the carpal
tunnel for the median nerve, the fibular neck for
113
114
M. Valle and M. P. Zamorani
ME
a
b
f
g
h
ME
d
c
e
Fig. 4.17a–h. Reversal reaction in leprosy. a Microscopic view of the sural nerve in a 25-year-old patient with leprosy reveals
the presence of Mycobacteria (purple) among the nerve tissue. Ziehl-Nielsen staining; original magnification ×800. b–h Right
ulnar nerve of a 22-year-old man with borderline tuberculoid leprosy examined at the elbow during the course of a reversal
reaction. b Long-axis and c short-axis gray-scale 12–5 MHz US images demonstrate high-grade swelling of the nerve (arrows)
with smooth fusiform enlargement of individual fascicles. ME, medial epicondyle. Corresponding d long-axis and e short-axis
color Doppler 12–5 MHz US images show dramatically increased blood flow within endoneural vessels. f–h Cranial to caudal
sequence of Gd-enhanced fat-suppressed MR images through the medial elbow show marked contrast enhancement into the
nerve (arrow)
the common peroneal nerve, the tarsal tunnel for
the tibial nerve). Compared with a chronically compressed nerve, however, the nerve enlargement is
more extensive and less circumscribed. In leprosy
patients, US is able to reveal nerve abnormalities
including nerve swelling, hypoechoic changes in
the epineurium, and loss of the fascicular echotexture (Fig. 4.17b,c) (Martinoli et al. 2000c).
These changes require multiple episodes of lepromatous reactions and a cumulative effect with time
to become apparent at US. In fact, nerve enlargement correlates well with patients who previously
underwent reversal reactions (Martinoli et al.
2000c). During the course of a reversal reaction,
the affected nerve segment is markedly thickened,
intensely painful and tender (Fornage and Nerot
1987; Martinoli et al. 2000c). The onset of these
reactions can be indicated by an intraneural hyperemic pattern at color and power Doppler imaging
(Fig. 4.17d-h) (Martinoli et al. 2000c). These signs
suggest rapid progression of nerve damage and a
poor prognosis unless antireaction treatment is
started (Martinoli et al. 2000c). More rarely, “cold”
soft-tissue abscesses may be seen arising from the
affected nerve and spreading through the fascial
planes of the limbs and extremities (Fig. 4.18).
4.1.8
Tumors and Tumor-Like Conditions
Peripheral nerve tumors include two main benign
forms – the schwannoma (also referred to as neurinoma or neurilemmoma) and the neurofibroma
– and the malignant peripheral nerve sheath tumor,
which most often derives from the malignant
(sarcomatous) transformation of a neurofibroma
(Murphey et al. 1999). In addition, other masses,
such as hemangiomas, lymphomas, and ganglion
cysts, may occasionally develop within the nerve
dissecting the fascicles and expanding inside the
neural tissue. The occurrence of these masses is
rare but they may cause nerve dysfunction and local
symptoms and should not be mistaken for the more
common nerve sheath tumors. Finally, a variety of
extrinsic soft-tissue neoplasms, both benign with
aggressive behavior and malignant, may involve a
nerve during their local spread.
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a
b
c
d
Fig. 4.19a–d. Peripheral nerve sheath tumors. a,b Schwannoma of the tibial nerve at the posterior leg. a Long-axis gray-scale
12–5 MHz US image with b schematic drawing correlation depicts the tumor as a globoid hypoechoic mass (arrows) which
develops eccentrically at the periphery of the nerve (arrowheads). c,d Neurofibroma of the median nerve at the distal forearm.
c Long-axis gray-scale 12-5 MHz US image with d schematic drawing correlation shows the tumor as a hypoechoic spindleshaped mass (arrows) expanding within the nerve and involving the fascicles (arrowheads). Focal enlargement of the nerve and
disappearance of the fascicular pattern is observed
unpublished data). Such abnormalities are usually
not seen in the distal end of the affected nerve. In
addition, schwannomas may be seen developing
from an individual fascicle, which appears diffusely
thickened even at a distance from the mass, whereas
the other fibers of the same nerve are displaced by
the bulk of the tumor but remain unaffected with
regard to size and echotexture (Fig. 4.21a). This can
explain why some schwannomas seems to have central continuity with the long axis of the nerve.
Neurofibromas, on the other hand, are intimately
associated with the parent nerve, developing in a
fusiform (not globoid) fashion, with the nerve entering and exiting from the extremities of the lesion
(Fig. 4.19c,d) (King et al. 1997; Lin and Martel
2001). Histopathologically, they are composed of a
mixture of cell types, the predominant one of which
has characteristics of the perineurial cells. As the proliferative cells of a neurofibroma grow, they spread
through the epineurium into the surrounding soft
tissue. Neurofibromas can be categorized into three
forms: localized, diffuse, and plexiform (associated
with type 1 neurofibromatosis). The localized variety
is the most common, accounting for approximately
90% of cases (Murphey et al. 1999). Often, a target
sign formed by a subtle central hyperechoic region
within the hypoechoic mass can be found in these
tumors, reflecting a central fibrotic focus surrounded
by peripheral myxomatous tissue (Fig. 4.21b–d) (Lin
et al. 1999). Neurofibromas are less hypervascular
than schwannomas at color and power Doppler imaging. Unlike localized neurofibromas, diffuse neurofibromas primarily involve the skin and the subcutaneous tissue and presents as a plaque-like elevation
of the skin with thickening of the subcutaneous tissue
(Fig. 4.22a,b) (Murphey et al. 1999).
As regards the malignant peripheral nerve sheath
tumor, the only findings which may make the exam-
Nerve and Blood Vessels
Fig. 4.20a–c. Cystic schwannoma. a,b
Long-axis a gray-scale and b color
Doppler 12–5 MHz US images over
the radial nerve (arrowheads) at the
arm with c MR-neurographic correlation show a rounded mass (arrows)
with intratumoral cystic changes,
related to accumulation of myxoid
matrix, in continuity with the parent
nerve (arrowheads). The tumor exhibits a hypervascular pattern made
up of peripheral and central color
Doppler signals
a
b
c
*
*
*
T
a
1 23
b
c
d
Fig. 4.21a–d. Peripheral nerve sheath tumors: peculiar US findings. Two different cases. a Schwannoma of the median nerve at
the bicipital sulcus. Long-axis 12–5 MHz US image depicts the tumor (T) as an eccentric hypoechoic mass in continuity with
the nerve (open arrowheads). At its proximal and distal ends, the tumor is connected with a swollen fascicle (asterisks), whereas
the other fascicles (white arrowheads) remain unaffected and displaced at the periphery of the mass. A split-screen image was
used, with the two screens aligned for an extended field of view. b–d Neurofibroma. b Long-axis and c short-axis 12–5 MHz US
images of a small neurofibroma in the thigh with d fat-suppressed T2-weighted MR imaging correlation reveal a well-delineated oval mass (arrows) in continuity with the posterior femorocutaneous nerve (arrowheads). The tumor is characterized by
concentric hypoechoic and hyperechoic layers (1, 2, 3) consistent with the sonographic target sign
117
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M. Valle and M. P. Zamorani
a
b
c
d
*
*
*
*
*
*
*
e
f
Fig. 4.22a–f. Neurofibroma: spectrum of US appearances. Three different cases. a,b Diffuse neurofibroma. a Transverse 12–5 MHz
US and b T1-weighted MR images of the suprapatellar region in a 10-year-old child without neurofibromatosis show an illdefined infiltrative mass (arrowheads) extending along the subcutaneous tissue of the anterior knee. c,d Sessile neurofibroma.
c Photograph of the right forearm of a 43-year-old man with neurofibromatosis shows a sessile cutaneous neurofibroma (arrow) associated with café-au-lait spots (arrowheads). d The 17–5 MHz US image demonstrates the sessile neurofibroma as a
superficial solid hypoechoic mass (straight arrows) arising from the dermis (curved arrow). e–f Plexiform neurofibromas. e
Long-axis 12–5 MHz US image over the sciatic nerve in an 8-year-old child with intra- and extra-abdominal neurofibromatosis
demonstrates multiple neurofibromas (asterisks) arising from individual fascicles of the sciatic nerve (arrows). f Coronal T2weighted MR image of the pelvis and the proximal thigh shows innumerable neurofibromas along the course of a thickened
and hyperintense sciatic nerve (arrows)
iner suspect that a nerve tumor is malignant are a
sudden increase in size of a previously stable nodule
and the presence of indistinct margins and adhesions of the mass with surrounding tissues. Especially in patients with type 1 neurofibromatosis,
a rapidly enlarging nodule indicates the need for
immediate biopsy.
Despite these differences, US cannot distinguish
among schwannoma, neurofibroma, and malignant
peripheral nerve sheath tumor (Lin and Martel
2001; Reynolds et al. 2004). US can contribute to
the preoperative assessment of the extent of disease,
by defining the relationship of the tumor to adjacent
neurovascular structures and surrounding muscles
and also by assisting surgical planning. After imaging assessment, fine needle aspiration biopsy of the
mass can be confidently performed under US guidance. During biopsy, excruciating pain is frequently
Nerve and Blood Vessels
triggered by the needle insertion. From the surgical
point of view, schwannomas may be shelled out preserving nerve continuity and function (Murphey et
al. 1999). In the postoperative setting, residual hypoechoic thickening of the nerve at the site of tumor
resection is almost invariably seen with US: this
should be regarded as a normal finding (Fig. 4.23).
Recurrence is unusual. In contrast, surgical resection of neurofibromas requires sacrificing the parent
nerve because the mass cannot be separated from
the nerve fascicles, and subsequent nerve grafting is
needed to preserve and restore function. Although
surgical management may be acceptable in cutaneous neurofibromas, deep-seated lesions are usually
managed conservatively to avoid functional deficit.
Type 1 neurofibromatosis (von Recklinghausen
disease), a relatively common (1:2500–3000 births)
inherited autosomal dominant disease related to
an alteration of a gene on chromosome-17, presents
with the typical clinical triad of cutaneous lesions
(café-au-lait spots), skeletal deformities (scoliosis),
and mental deficiency. Widespread involvement by
neurofibromas of the localized, diffuse, and plexiform variety occurs with tumors arising from small
dermal nerves and large deep-seated nerves. In
neurofibromatosis, localized neurofibromas often
involve the dermis and the subcutaneous tissue: when
pedunculated, they are referred to as the “fibroma
molluscum” (Fig. 4.22c,d) (Murphey et al. 1999). In
plexiform (multinodular) neurofibromatosis – the
pathognomonic form of the disease – innumerable
neurofibromas are generated from the fascicles of
a large nerve trunk, which is typically involved for
a long segment together with its branches, leading
to the so-called “bag-of-worms” appearance of the
affected nerve at gross inspection and US imaging
that results from the diffuse tortuous nerve thickening (Figs. 4.22e,f, 4.24) (Murphey et al. 1999). A disfiguring giant enlargement of the extremities may
be associated, so-called elephantiasis neuromatosa
(Murphey et al. 1999). Plexiform neurofibromas
are indistinguishable from the more rare plexiform
schwannomas which sporadically occur in children and young adults: the latter are not associated
with type 1 neurofibromatosis and do not undergo
malignant transformation (Fig. 4.25) (Ikushima et
al. 1999; Katsumi et al. 2003).
4.1.8.2
Hemangioma and Non-Hodgkin Lymphoma
Nerve hemangiomas are extremely rare tumors arising from the endothelial lining of the endoneurium
from which new vessels arise or infold within nerves
from the perineural tissue. Most are recognized in
children and young patients; there is no gender
prevalence. The tumors tend to enlarge with age, or
because of stimulating factors such as and trauma
(Bilge et al. 1989). Nerve hemangiomas have a predilection for the median nerve; a persistent median
artery has been advocated to explain this prevalence
(Prosser and Burke 1987). Clinical findings include
palpable nerve swelling at the distal forearm with or
without symptoms of carpal tunnel syndrome. US
reveals a markedly swollen median nerve containing
large intraneural fluid-filled spaces separating the
fascicles (Fig. 4.26). Typically, these anechoic spaces
are oriented according to the long-axis of the nerve
and compressible with the transducer. Color and
power Doppler imaging show slow-flowing blood
within them (Fig. 4.26c). Venous waveforms are pre-
Fig. 4.23. Peripheral nerve sheath tumors: postsurgical findings. Long-axis 12–5MHz US image over the tibial nerve (arrowheads)
at the mid-posterior leg in a 48-year-old woman who was previously operated on for schwannoma shows residual hypoechoic
thickening (arrows) of the nerve at the site of tumor resection with loss of the fascicular echotexture. This finding was stable at
3 year follow-up. A split-screen image was used, with the two screens aligned for an extended field of view
119
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M. Valle and M. P. Zamorani
*
*
*
* *
*
*
* * *
Fig. 4.24. Plexiform neurofibromatosis. Long-axis extended-field-of-view 17–5 MHz US image over the median nerve (arrows)
at the forearm in a patient with neurofibromatosis shows multiple plexiform neurofibromas (asterisks), some of which have a
central hyperechoic area representing the target sign. The median nerve is markedly enlarged and shows a convoluted multinodular appearance
a
b
c
d
Fig. 4.25a–d. Plexiform schwannoma. a Photograph of the right hand of a 4-year-old child with an elongated palpable lump
(arrows) on the palm, growing in between the third and fourth metacarpals. b Extended-field-of-view 17–5 MHz US image oriented along the long axis of the lump with fat-suppressed c T2-weighted and d postcontrast GRE T1-weighted MR imaging correlation demonstrates a multinodular hypoechoic mass (arrows) made up of swollen convoluted fascicles arising from the median
nerve (arrowheads) and branching distally. The tumor appears hyperintense in T2 and after gadolinium administration
dominant at spectral Doppler analysis. Surgical neurolysis of nerve hemangiomas is not recommended
because intraneural vessels are part of the “vasa
nervorum” system and due to the intermingled distribution of vessels with fascicles. In symptomatic
patients, carpal tunnel release may be performed to
improve the clinical symptoms.
Primary non-Hodgkin lymphomas affecting
peripheral nerves are very rare. Most involve the
sciatic nerve and are the result of direct spread from
adjacent tumors (Roncaroli et al. 1997). Peripheral
neuropathy may also be appreciated in the absence
of direct involvement of the nerve as a paraneoplastic manifestation of lymphoproliferative disorders.
From the histopathologic point of view, the affected
nerves show extensive neoplastic infiltration of the
endoneurium and perineurium. The nerve fascicles
are separated by diffuse infiltrates of neoplastic
lymphoid cells contained within a thickened epineurium (Eusebi et al. 1990). US reveals a heterogeneous nerve mass with distortion and swelling of the
individual fascicles (Fig. 4.27). The treatment usually consists of chemo- and radiotherapy (Pillay et
al. 1988).
Nerve and Blood Vessels
*
*
*
*
d
a
* *
b
c
e
f
Fig. 4.26a–f. Hemangioma of the median nerve in a 40-year-old woman with carpal tunnel syndrome and a large intramuscular
hemangioma extending through the flexor muscles of the forearm down to the carpal tunnel. The patient underwent release of
the retinaculum and partial resection of the mass with removal of the flexor digitorum superficialis muscle. a Long-axis and
b short-axis 17–5 MHz US images obtained at the distal radius show an enlarged median nerve (arrows) with intranervous
abnormal fluid-filled spaces (asterisks) running alongside the fascicles (arrowheads). c Longitudinal color Doppler 12–5 MHz US
image reveals slow-flowing blood within the intraneural spaces indicating a hemangioma. Vessels are compressible and exhibits
venous waveforms. d,e Correlative transverse d T1-weighted and e T2-weighted MR images show increased T2 signal intensity
in the epineurium surrounding the fascicles of the median nerve (arrows), due to the presence of abnormal vessels within the
nerve substance. f Digital subtraction angiography confirms the presence of a venous network in the median nerve
4.1.8.3
Intraneural Ganglia
The incidence of intraneural ganglia is relatively
low, affecting most frequently the common peroneal
nerve (Yamazaki et al. 1999). This nerve originates at
the apex of the popliteal fossa from the sciatic nerve
and moves downward to the fibular head, where it
divides into its two terminal branches: the deep and
the superficial peroneal nerve. Around the fibular
neck, the deep peroneal nerve gives off a small recurrent articular branch to supply the capsule of the
superior tibiofibular joint. The capsular ending of
this small branch may lead to the development of
intraneural ganglia (Spinner et al. 2003, 2005). In
fact, this branch serves as a conduit for cyst fluid to
pass from the joint space into the nerve (Spinner
et al. 2003). The joint fluid dissects the epineurium
among the fascicles and moves toward the deep peroneal nerve, the common peroneal nerve and even the
sciatic nerve, forming an elongated intraneural cyst.
As described in Chapter 14, intraneural ganglia do not
have a fibrous capsule or a synovial lining and must
be differentiated from the more common extraneural
ganglia. As an extension of the superior tibiofibular
joint, they appear as spindle-shaped cystic masses
contained within the nerve sheath that grow in the
space between the epineurium and the nerve fascicles
(Martinoli et al. 2000b).
4.1.8.4
Nerve Encasement by Extrinsic Neoplasms
Extrinsic soft-tissue tumors may involve normal
nerves by contiguity. They may either displace and
compress the nerve at the periphery of the mass
without infiltrative signs or can incorporate the
nerve. In the first instance, the integrity of the nerve
can be preserved at surgery after removal or debulking of the mass. In the latter, the surgical procedure
is obliged to sacrifice the encased nerve together
with the tumor (Fig. 4.28). US may aid in assessing
the extent of tumor preoperatively, and in defining
the exact relationship of the mass with the nerve and
its divisional branches (Fig. 4.29).
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Nerve and Blood Vessels
*
*
*
a
**
b
Fig. 4.29a,b. Nerve involvement by extrinsic tumors. a Oblique longitudinal 12-5 MHz US image over the popliteal fossa demonstrates a large lipomatous mass (asterisks) encasing the peroneal nerve (arrowheads). A split-screen image was used, with
the two screens aligned for an extended field of view. b Gross surgical view shows the bifurcation of the sciatic nerve (arrow)
into the tibial (open arrowheads) and the peroneal (white arrowheads) nerves. This latter nerve can be seen infolding within
the mass (asterisks). Pathologic examination revealed a liposarcoma
4.2
Blood Vessels
An in-depth complete treatise on the arteries and
veins running in the limbs and extremities and
related-pathology is beyond the scope of a book
on the musculoskeletal system. Here, we will focus
on general aspects of vascular pathology related to
musculoskeletal diseases. Some concepts are specifically addressed in other chapters of the book.
The analysis of the proper vascular pathology of
limb arteries and veins, such as atherosclerotic disease and venous insufficiency, is more appropriately
dealt with in other textbooks and specific literature
(Polak et al. 1989; Edwards and Zierler 1992;
Foley et al. 1989; Fraser and Anderson 2004).
4.2.1
Histologic Considerations
Based on their histologic architecture, the arteries
can be divided into four different groups: elastic
arteries, medium-sized muscular arteries, small
arteries, and arterioles (i.e. the radial and ulnar
arteries belong to the medium-sized muscular
group). Elastic arteries are the largest in the body;
they expand when the heart contracts and return
to a normal caliber in diastole. Muscular arteries are small and middle-sized vessels with a relatively narrow lumen and thick walls consisting of
circumferentially arranged smooth muscle fibers
which restrict the lumen when they contract. The
tonus of the smooth muscle component depends on
the autonomic nervous system and is responsible
for the round cross-sectional shape of the arteries,
for blood pressure levels, and for regulatory functions of blood flow (i.e. increased flow volume in
the skeletal muscles during exercise). The arterial
wall is composed of three concentric layers: the
intima (inner tunica) containing the endothelial
lining; the media (intermediate tunica) housing
smooth muscle tissue; and the adventitia (outer
tunica) characterized by fibrous tissue merging
with the loose connective space around the vessel
(Fig. 4.30a). In a muscular artery, the lamina elastica interna lies between the intima and the media,
whereas the lamina elastica externa separates the
media from the adventitia.
Compared with the arteries, veins have thinner
walls and larger lumens. One of their main function
is to store blood, and they need muscle to push the
blood back to the heart. Because the venous walls
may collapse, the vessel shape varies depending on
the surrounding tissue conditions, including the
subject’s positioning and gravity. In contrast to the
arteries, the layering of the venous wall is not so distinct: the intima is very thin (only the largest veins
contain discrete amount of subendothelial connective tissue); the media is thinner than the adventitia,
and the two layers blend into each other. Peripheral
veins may be double or multiple when accompany a
medium-sized artery and are, in general, more variable than the arteries themselves, with anastomoses
very often occurring between them. Many small
to medium-sized veins contain valves (Fig. 4.31a).
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Nerve and Blood Vessels
These are loose, pocket-shaped folds of the intima,
which extend into the lumen of the vein. The opening of the cusps prevents backflow of blood and
encourages flow toward the heart. Blood flowing
toward heart passes the pockets (Fig. 4.31a,b); if the
flow reverses, blood fills the pockets thus occluding
the lumen of the vein and preventing the pooling of
blood (Fig. 4.31c,d). When a subject is standing, the
venous return from the legs depends mainly on the
activity of calf muscles, the so-called calf pump.
4.2.2
Normal US Anatomy and Scanning Technique
Because the limb arteries are relatively superficial,
very good quality US images are usually obtained
with the transducers used for musculoskeletal applications. Similar to other applications, selection of
the appropriate transducer frequency depends on
the patient’s build and the depth of the vessel to be
examined. Changing the machine settings from a
musculoskeletal application to a vascular-specific
setting and lowering the gain may help to reduce
artifactual speckles within the vessel lumen that
may generate confusion with thrombus. In normal
states, limb arteries appear as pulsatile structures:
pulsatility is better appreciated on short-axis planes
during prolonged observation. This sign is usually
sufficient to assess limb arteries during a conventional study of the musculoskeletal system for unrelated purposes.
a
Based on correlative microdissection studies and
the use of high-resolution intravascular probes, US
demonstrates the normal wall of a small to mediumsized muscular artery as a three-layered structure.
An inner bright acoustic linear echo derives from the
interface of blood with the intima and the lamina elastica interna, and an outer echogenic layer is produced
by reflection at the interface between the lamina elastica externa and the adventitia (Fig. 4.30b) (Chong
et al. 1993; Siegel et al. 1993). Being primarily composed of smooth muscle, the tunica media appears
as a mid-hypoechoic band intervening between the
two echogenic layers (Chong et al. 1993; Siegel et al.
1993). In contrast, the wall of elastic arteries, whose
media have a high elastin content, appears uniformly
echogenic (Chong et al. 1993; Siegel et al. 1993;
Martin et al. 1997).
When vascular disease is suspected, color Doppler
imaging and spectral Doppler analysis can complement gray-scale findings to determine patency and
vessel narrowing. As a rule, Doppler examination
should be performed along the longitudinal axis
of the vessels with a Doppler angle of 60° or less
(Fig. 4.32a). Because most vessels of the extremities
course parallel to the skin, beam steering should be
used as a default setting to obtain adequate Doppler
angles. At rest, spectral Doppler analysis of flow
waveforms and color Doppler imaging of the upper
and lower limb arteries demonstrate a characteristic pattern of high distal resistance (Fig. 4.32b). In
response to exercise and muscle activation, vasodilation usually produces a higher forward flow
b
c
Fig. 4.32a–c. Normal Doppler imaging findings in the brachial artery. a Pulsed Doppler analysis shows normal high-resistance
pulsatile flow with oscillations in diastole. A steered color box is used to obtain an adequate Doppler angle and clear-cut Doppler
tracings. b Color Doppler imaging appearance of flow in the high-resistance brachial artery (a). There is evidence of color flow
signal in systole (1) but not in the early diastolic phase (2). Continuous blood flow is detected in the adjacent brachial vein (v)
with complete filling of the vessel lumen, indicative of patency. c Following repeated fist clenching, the resulting vasodilation
produces a higher forward flow throughout the cardiac cycle, particularly in diastole
125
Nerve and Blood Vessels
which must be known by the sonologist when performing a US study of the musculoskeletal system.
Other vascular pathology, even if relevant, has been
omitted as outside the aims of this book.
4.2.3.1
Arterial Disorders
Because of their superficial location and close apposition to the bones, the arteries of the limbs and
extremities are particularly vulnerable to traumatic
injuries. Based on its pathomechanism, arterial
trauma can be arbitrarily subdivided into three main
types: acute direct injuries following a penetrating
wound by a sharp object or blunt arterial lacerations
related to major stretching or contusion trauma
(including high-grade sprains, bruising, dislocated
joints and fracture-dislocations near arteries – such
as supracondylar humeral fractures for the brachial
artery, glenohumeral dislocations for the axillary
artery, supracondylar femoral fractures for the popliteal artery, and knee dislocation for the posterior
tibial artery); chronic repeated microtrauma causing progressive damage to the vessel wall that may
lead to pseudoaneurysms, aneurysms, and vessel
occlusion; and iatrogenic injuries resulting in either
thrombosis or local hemorrhage. When major arterial trunks of the limbs are involved, direct traumatic injuries are clinical emergencies and, in most
cases, require immediate surgical repair to avoid
acute limb ischemia, hypotensive shock, and death
related to blood loss (Davison and Polak 2004).
Doppler US has been advocated for the diagnosis
of acute arterial trauma to the extremities in an
emergency setting, but its sensitivity is lower than
that of CT angiography (Fry et al. 1993; Knudson
et al. 1993; Miller-Thomas et al. 2005; Rieger et
al. 2006). Similar to MR imaging, color Doppler US
has substantial limitations in this field, related to
the considerable amount of time needed to make
the diagnosis. In addition, color Doppler imaging is
operator-dependent, may be inadequate in the evaluation of arterial flow distal to an arterial injury, is
susceptible to confusion created by collateral vessels, and may be unsuitable in patients with open
wounds (Rieger et al. 2006).
Color Doppler imaging seems more useful for
identifying and monitoring minor arterial injuries occurring during trauma that do not require
specific immediate operative management – such
as intimal lesions, pseudoaneurysms, and minor
vessel occlusions – in order to assess whether they
resolve or progress (Schwartz et al. 1993). Similarly, gray-scale US and Doppler imaging techniques
seem more relevant for identifying incidental arterial damage secondary to chronic microtrauma and
overuse syndromes. These lesions typically occur
in the hand, where the branches of the ulnar artery
can be pinched between the skin and the underlying hamate as the result of repeated external trauma
against the palm (Fig. 4.34). This condition, which
is commonly referred to as “hypothenar hammer
syndrome,” results in intimal injury, thrombosis or aneurysm with subsequent digital ischemia,
pain or a palpable mass in the hand (see also
Chapter 10) (Okereke et al. 1999; Liskutin et al.
2000; Velling et al. 2001). Similar vascular abnormalities may occur at the level of the dorsalis pedis
artery following repeated blunt trauma over the
dorsum of the ankle and midfoot (Yamaguchi et al.
2002; Ozdemir et al. 2003). In these cases, US and
Doppler techniques should be the first-line imaging modality. Digital subtraction angiography or
contrast-enhanced MR-angiography may still be
required by the vascular surgeon for precise preoperative planning. Other uncommon causes of closed
arterial damage associated with abnormalities of
the musculoskeletal system are related to anatomic
variants, such as: injury to the popliteal artery due
to osseous abnormalities in patients with hereditary multiple exostoses (see Chapter 14) (Chamlou
et al. 2002); popliteal artery entrapment syndrome,
produced by anomalous proximal insertion of the
medial head of the gastrocnemius (Fig. 4.35) (see
Chapter 14) (Wright et al. 2004); and brachial artery
entrapment in the arm secondary to the presence of
a supracondylar process and the Struthers ligament,
so-called supracondylar process syndrome (see
Chapter 7) (Talha et al. 1987).
As regards iatrogenic injuries, procedures of
arterial catheterization may be responsible for
vascular dissections, soft-tissue hematomas, pseudoaneurysms, and arteriovenous fistula formation
(Clevert et al. 2005; Schwartz et al. 1991). These
lesions are typically located at the puncture site,
including the groin for the femoral artery and its
divisional branches (see Chapter 12) (Roubidoux
et al. 1990; Helvie et al. 1988) and the medial arm
for the brachial artery (see Chapter 7) (Chuang et
al. 2002). Compression-based femoral and median
neuropathy is a well-established complication of
hematomas and pseudoaneurysms following arterial catheterization (see Chapter 7) (Jacobs et al.
1992; Chuang et al. 2002). Color Doppler imaging
is useful in differentiating complications of femoral
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a
b
e
Carpal
tunnel
Hamate
c
f
d
Fig. 4.34a–f. Hypothenar hammer syndrome. Two different cases of manual workers – one a car mechanic, the other a weightlifter – who had occupational hammering in their right hands. a–d Occlusion of the ulnar artery. a Transverse and b longitudinal 15–7 MHz US images over the hypothenar eminence with c schematic drawing and d gross surgical view correlation show
complete occlusion of the ulnar artery (arrows) at the point where it courses adjacent to the hamate hook. Note the adjacent
uninjured sensory branch of the ulnar nerve (arrowhead). Operative view demonstrates a thickened pale artery coursing adjacent to the ulnar nerve. The patient had ischemic symptoms in the fourth and fifth fingers. e,f Aneurysm of the ulnar artery.
e Transverse and f longitudinal 12–5 MHz US images over the hypothenar eminence demonstrate an aneurysm (white arrows)
of the ulnar artery (large open arrow). There are no echoes evident in the lumen, indicating absence of thrombus. The patient
complained of only mild pain over the aneurysm. Arrowheads, sensory branch of the ulnar nerve
*
a
a
b
a
d
a
a
c
a
e
*
g
a
f
h
i
Fig. 4.35a–i. Popliteal artery entrapment syndrome. a–c Series of transverse 17–5 MHz US images of the popliteal fossa with
d–f T1-weighted MR imaging correlation in a 45-year-old man with exercise-induced claudication of his right lower extremity
demonstrate an anomalous medial course of the popliteal artery (a), which passes from medial to lateral across an abnormal
muscle band (dashed line in a-c, arrows in d-f) lying in the popliteal fossa. At color Doppler imaging (not shown), the vessel
occlusion initiated at the point where the artery is closely apposed to the posteromedial corner of the medial femoral condyle
(asterisk) and is, therefore, vulnerable to compression by the anomalous muscle. MR imaging allowed this muscle abnormality
to be classified as type 2. g,h Spectral Doppler analysis performed g at the upper-popliteal artery level and h downstream in
the tibial artery at the proximal leg reveals g normal pulsatile flow cranial to the occlusion and h dampening of the distal flow
waveforms. i Anteroposterior digital subtraction angiography shows segmental occlusion (arrowheads) of the popliteal artery
with collateral filling through the geniculate arteries
Nerve and Blood Vessels
artery catheterization, such as hematoma, pseudoaneurysm, and arteriovenous fistula. It demonstrates arterial pseudoaneurysm as a perivascular
sac with thickened echogenic walls (mural thrombus) containing swirling flow with alternating red
and blue colors (Fig. 4.36a–c). In general, the neck
connecting the artery with the pseudoaneurysm is
better recognized on color Doppler imaging than
on gray-scale US (Schwartz et al. 1991). At Doppler spectral analysis, blood flow in the neck exhibits bidirectional high velocities as blood enters the
cavity from the damaged artery in systole (flow displayed above the baseline) and exits in diastole (flow
displayed below the baseline), the so-called “to-andfro” signal (Fig. 4.36d) (Sacks et al. 1989). On the
other hand, characteristic findings of arteriovenous
fistulas include: visible connection between artery
and vein, multicolored (mosaic pattern) speckled
mass at the fistula site, spreading of color pixels into
the perivascular soft tissues, high diastolic flow in
the arterial waveform proximal to the fistula site,
decreased flow in the artery caudal to the fistula, and
high-velocity turbulent flow, sometimes with a pulsatile component, in the efferent vein (Helvie and
Rubin 1989; Roubidoux et al. 1990). US-guided procedures to treat pseudoaneurysms with direct probe
compression and thrombin injection are described
elsewhere (see Chapter 12). In the postoperative setting, US and Doppler techniques have proved valuable in evaluating by pass grafts to detect the onset
of early failure, including stenoses, thrombosis, and
infectious collections (Fig. 4.37).
4.2.3.2
Venous Disorders
Direct trauma to the deep and superficial venous
system only occasionally produces a vascular
lesion, such as an aneurysm or a vein occlusion.
Although rare, the possibility of a venous aneurysm should, however, be taken into account so as
not to confuse an aneurysm with either a ganglion
cyst (when patent) or a solid soft-tissue mass (when
thrombosed). Demonstration of the continuity of
the dilated venous segment with a superficial, even
small, vein and blood flow detected within the
mass may help the diagnosis (Fig. 4.38a–d). When
thrombosed, venous aneurysms may be a diagnostic
challenge because they appear as nonspecific solid
avascular masses (Fig. 4.38e). Post-traumatic vein
thrombosis may occasionally be encountered following muscle strains as a result of stretching of the
vessel walls. This kind of trauma typically occurs in
the infrapopliteal veins (the gemellary veins are the
most commonly involved) of patients with tennis
leg lesion (see Chapter 15) (Delgado et al. 2002).
Post-traumatic muscle edema and hematoma may
also produce compression and then occlusion of
low-pressure intramuscular veins. Similarly, pro-
*
a
b
c
d
Fig. 4.36a–d. Iatrogenic pseudoaneurysm of the brachial artery. a Photograph of the anterior right elbow of a 72-year-old
woman presenting with an enlarging pulsatile soft-tissue lump (arrows) that developed after a vein cannulation procedure.
Transverse b gray-scale and c color Doppler 17–5 MHz US images over the lump reveal a large complex mass (straight arrows)
with thickened walls and a central cavity filled with whirling flow (asterisk) consistent with a pseudoaneurysm of the brachial
artery (arrowheads). The slow flow in the pseudoaneurysm makes blood echogenic at gray-scale imaging. Color Doppler imaging demonstrates continuity of the pseudoaneurysm cavity with a displaced brachial artery by means of a thin neck (curved
arrow). d Spectral Doppler analysis obtained in the communicating tract displays bidirectional velocities as the forward flow
(1) in systole is ejected (2) in diastole
129
130
M. Valle and M. P. Zamorani
*
*
*
*
a
b
*
*
*
*
c
Fig. 4.37a–c. Abscess around a bypass graft. a Long-axis and b short-axis 17–5 MHz US images over an occluded aorto-femoral
bypass graft (arrows) in a 70-year-old diabetic patient with amputated lower leg and clinical signs of sepsis. Note the shrunken
appearance of the graft surrounded by a fluid collection (asterisks). c Preoperative percutaneous drainage of the collection.
The catheter (curved arrows) is seen inside the almost empty abscess (asterisks). As shown in the insert, aspiration resulted in
purulent material
*
c
a
*
b
d
e
Fig. 4.38a–e. Venous aneurysms. Two different cases. Long-axis a,b gray-scale and c,d color Doppler 12–5 MHz US images
obtained a,c,d without and b with probe compression over a compressible soft-tissue mass of the dorsum of the mid-foot in
a patient with healed mid-tarsal fractures reveal a fluid-filled oval lesion (asterisks) connected at its opposite ends to a small
superficial vein (arrowheads). As shown in b, the mass is fully compressible without internal thrombus. This sign, together with
demonstration of the venous ends and of internal blood flow at color Doppler imaging, may avoid confusion with ganglion cysts.
While releasing probe compression, blood flow (arrow) can be seen entering the aneurysm from the parent vein (arrowhead)
to completely fill its cavity. e Thrombosed superficial varicose vein. Sagittal 12–5 MHz US image over the posteromedial aspect
of the leg shows a polycyclic hypoechoic mass (arrows) in continuity with a thin pedicle (arrowheads) directed toward depth,
an appearance nonspecific at US examination. After surgical resection, this mass proved to be a thrombosed varix
longed absence of contracture of the calf muscles
as a result of local pain and post-traumatic immobilization may be implicated as a possible cause of
venous thrombosis.
In the lower limb, compression US and color
Doppler imaging can easily diagnose deep venous
thrombosis and distinguish a vascular problem
from other musculoskeletal conditions that may
mimic it, including a ruptured Baker cyst (see
Chapter 14) or a post-traumatic hematoma (see
Chapter 15). The classic description of venous thrombosis is that of an enlarged vein with thickened walls
containing echogenic material with multiple sur-
rounding collateral vessels (Murphy and Cronan
1990). Based on the imaging findings, US can distinguish complete occlusive (Fig. 4.39a,b) from partial
non-occlusive thrombosis (Fig. 4.39c,d). Non-occlusive thrombus may not alter the spectral Doppler
flow pattern. In some instances, the head of the
thrombus may float freely within the vessel lumen
(Fig. 4.39e,f). This finding should be indicated in the
report as it relates to an increased risk of embolism.
Although many have tried to date the thrombus on
the basis of its reflectivity, such attempts have been
ineffective (Murphy and Cronan 1990). In chronic
vein thrombosis, recanalization of the thrombus
Nerve and Blood Vessels
a
b
1
2
c
d
*
*
e
f
*
*
g
i
a
h
A
j
Fig. 4.39a–j. Vein thrombosis: spectrum of US appearances in different patients. a,b Complete vein thrombosis. a Short-axis and
b long-axis 12–5 MHz US images of an intramuscular vein (arrowheads) of the soleus containing highly echogenic material
consistent with chronic thrombus. This vein was noncompressible at US. c,d Partial vein thrombosis. c Short-axis gray-scale
12–5 MHz US image of the popliteal vein shows a distended lumen containing reflective material (1) suggestive of thrombosis.
d Correlative transverse color Doppler 12–5 MHz US image confirms the presence of an area of non-occlusive thrombus with
blood flow surrounding the periphery of the clot with a crescentic appearance. Note that part of the non-echogenic lumen (2)
was also thrombosed indicating successive phases of thrombus apposition with time. e,f Floating thrombus. e Short-axis and f
long-axis 12–5 MHz US images of the greater saphenous vein demonstrate the proximal head of the thrombus (arrow) floating
freely in the patent vessel lumen (asterisk). During real-time observation, the thrombus could be seen knocking against the
vessel wall. This kind of thrombus correlates with the highest risk of embolism. g,h Recanalized thrombus. Long-axis g grayscale and h color Doppler 12–5 MHz US images over the posterior knee show an enlarged popliteal vein (arrowheads) containing heterogeneous thrombus. Tiny longitudinal hypoechoic channels with flow (curved arrow) are seen inside the thrombus
reflecting a process of partial recanalization. Observe the popliteal artery (a) and superficial venous collaterals (asterisks). i,j
Chronic vein occlusion. i Short-axis and j long-axis 12–5 MHz US images of the small saphenous vein demonstrate an occluded
vessel (arrowheads) which appears markedly narrowed. The schematic drawings on the right side of the US images report the
cross-sectional profile of a vein with disposition of thrombus (gray) and patent lumen (white) in relation to the different types
of vein thrombosis described
131
132
M. Valle and M. P. Zamorani
*
*
a
v
a
b
c
d
Fig. 4.40a–d. Common vascular and soft-tissue abnormalities associated with vein thrombosis. Three different cases. a Opening of collateral vessels. Long-axis color Doppler 12–5 MHz US image over a thrombosed greater saphenous vein (asterisks)
demonstrates a process of partial recanalization (curved arrow) by a collateral vessel (arrowhead). b Muscle edema related to
venous stasis. Short-axis gray-scale 12–5 MHz US image over the bicipital fossa shows a thrombosed cephalic vein (arrows) that
lies superficial to the brachial artery (a), the median nerve (curved arrow), and a patent brachial vein (v). Note the subfascial
edema (arrowheads) involving the biceps brachii muscle as a result of venous stasis. c,d Superficial thrombophlebitis of the
lower leg. c Short-axis and d long-axis 12–5 MHz US images over a thrombosed lesser saphenous vein (arrows) demonstrate
ill-defined vessel walls and a wide hyperechoic halo (arrowheads) surrounding the thrombosed vein consistent with reactive
inflamed subcutaneous fat
a
b
c
d
e
f
Fig. 4.41a–f. Angioleiomyoma. a,b Sagittal a gray-scale and b color Doppler US images of the palm demonstrates a subcutaneous sharply delineated solid hypoechoic mass (arrows) with a large arterial pedicle branching within (arrowhead). c Spectral
Doppler analysis of intratumoral vessels shows high-resistance arterial waveforms. d–f Sagittal d T1-weighted, e postcontrast
T1-weighted and f fat-suppressed T2-weighted MR imaging correlation reveal a predominantly hyperintense mass (arrows) in
T2-signal intensity and after gadolinium administration. In the postcontrast image, small hypointense foci are visible within
the tumor
Nerve and Blood Vessels
may present as a network of thin hypoechoic channels of flow within the echogenic thrombus, eventually causing obvious clot resorption and reopening
of the vessel (Fig. 4.39g,h). Both reduction in spontaneous flow and incomplete vein compressibility
accompany these stages in the post-phlebitic limb.
Collateral vessels are often seen restoring venous
patency (Fig. 4.40a). If recanalization does not occur,
chronically thrombosed veins are characterized by
narrowed size, thickened and irregular walls and
collateral vessel formation (Fig. 4.39i,j). Soft-tissue
or muscle edema may be ancillary findings with
vein thrombosis as a consequence of venous stasis
(Fig. 4.40b). As detailed in Chapter 15, US may easily
diagnose thrombophlebitis, which requires treatment with anti-inflammatory drugs and not, at least
routinely, anticoagulation therapy (Fig. 4.40c,d).
4.2.4
Vascular Tumors
The most frequent vascular tumor, soft-tissue
hemangioma, is not dealt with in this chapter as
it has already been reported in its various forms:
in Chapter 2 as part of skin and subcutaneous
tissue masses, in Chapter 3 as regard its intramuscular location, and in Chapter 5 in relation to its
synovial type. Similarly, the glomus tumor will be
described in Chapter 11. A vascular-related tumor
that has received specific attention in the US literature is angioleiomyoma (vascular leiomyoma),
a rare benign histotype arising from the tunica
media of the veins, composed of a conglomerate of
thick-walled vessels associated with smooth muscle
(Sardanelli et al. 1996; Hwang et al. 1998). It is
most often found in an extremity, particularly the
lower leg and the foot (50–70% of cases) (Hwang
et al. 1998). Angioleiomyoma causes pain that is
often related to problems with footwear and may
be triggered by even light trauma. US demonstrates
a sharply demarcated solid hypoechoic rounded
nodule, usually less than 2 cm in diameter, with
one or more arterial pedicles branching within
(Fig. 4.41). Spectral Doppler analysis shows a highresistance flow pattern (Sardanelli et al. 1996).
In clinical practice, angioleiomyoma should be
considered in the differential diagnosis of painful
nodular lesions of the extremity. Other vascular
tumors includes rare aggressive histotypes, such as
hemangioendothelioma, hemangiopericytoma, and
angiosarcoma, all of which are characterized by a
nonspecific US appearance.
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Bone and Joint
5
Bone and Joint
Maria Pia Zamorani and Maura Valle
CONTENTS
5.1
5.1.1
5.1.2
5.1.3
5.1.3.1
5.1.3.2
5.1.4
5.1.5
5.1.5.1
5.1.5.2
5.1.5.3
5.1.5.4
5.1.6
5.2
5.2.1
5.2.2
Bone 137
Histologic Considerations 137
Normal US Anatomy and
Scanning Technique 138
Outgrowths 142
Anatomic Variants 142
Bone Exostoses 142
Defects 142
Irregularities of the Cortical Outline
Acute Fractures 143
Stress Fractures 145
Fracture Healing 146
Erosions 148
Osteomyelitis 149
5.1
Bone
5.1.1
Histologic Considerations
143
5.2.3.6
5.2.3.7
Joint 150
Histologic Considerations 150
Normal US Anatomy and
Scanning Technique 153
Pathologic Changes 156
Joint Effusion 156
Rheumatoid Arthritis and
Other Inflammatory Arthropathies
Septic Arthritis 162
Traumatic Injuries 163
Degenerative Joint Disease
(Osteoarthritis) 166
Deposition Diseases 169
Postoperative Complications 173
5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
Space-Occupying Masses 173
Bone Tumors 173
Pigmented Villonodular Synovitis 176
Lipoma Arborescens 178
Synovial Osteochondromatosis 178
Synovial Hemangioma 179
5.2.3
5.2.3.1
5.2.3.2
5.2.3.3
5.2.3.4
5.2.3.5
References
137
158
180
M. P. Zamorani, MD
Unité de Recherche et Dévelopement, Clinique des Grangettes,
7, ch. des Grangettes, 1224 Genève, Switzerland
M. Valle, MD
Staff Radiologist, Reparto di Radiologia, Istituto Scientifico
“Giannina Gaslini”, Largo Gaslini 5, 16148 Genova, Italy
All bones consist of peripheral cortical (compact)
bone and central medullary (trabecular or cancellous) bone. In long bones, there is an inverse relationship between the amount of cortical and cancellous bone at any given site: in the diaphysis, the
cortical bone is thick whereas the trabecular bone
is sparse; conversely, metaphyseal and epiphyseal
regions are characterized by thin cortical bone and
prominent cancellous bone. In addition to bone
trabeculae, the medullary cavity contains bone
marrow, including yellow marrow (housing fat and
connective tissue) and red marrow (consisting of
hematopoietic cells, fat and connective tissue). The
distribution of hematopoietic and fatty marrow is
dependent on age and metabolic state (Ricci et al.
1990). The outer surface of cortical bone is invested
by the periosteum—a dense fibrous connective
tissue layer that is anchored to the cortical bone
by means of perforating Sharpey fibers—which
plays a role in allowing rapid healing of fractures.
The periosteum thickness varies depending on age:
it is thicker and more active in children. Nutrient arteries and emissary veins cross the cortical
bone through the nutrient foramina. In mature
long bones, they are most often observed at the
diaphysis level. In terms of histogenesis, the bone
develops from two distinct processes referred to as
intramembranous and endochondral ossification
(Erickson 1997). Intramembranous ossification
occurs through direct mineralization of vascular
connective tissue and is responsible of the growth
of flat bones; it also contributes to the width of
the shaft of long bones. Endochondral ossification
arises within a cartilage model and is responsible
for the longitudinal growth of long bones and the
formation of the axial skeleton (Fig. 5.1).
138
M. P. Zamorani and M. Valle
*
*
Cartilage
Bone
c
a
Cuboid
Bone
d
b
Fig. 5.1a–d. Endochondral ossification. a,b Coronal 12–5 MHz US images over the lateral midfoot with c,d schematic drawing
correlation show the growing cuboid at a,c 1 year of age and b,d at the end of development. The cuboid is a square bone with
right angles (arrowheads). Initially, the cartilage (asterisks) forms a square model reflecting the definitive appearance of bone.
The primary center of ossification is visible in the center of the future bone as a hyperechoic rounded image (arrows). During
growth, endochondral ossification advances toward each end of the cartilaginous model. At the end of this process, the primary
center has reached the ends of the cartilaginous model and assumes the definitive square shape
5.1.2
Normal US Anatomy and Scanning Technique
There is no doubt that radiography is the first-line
imaging modality for assessment of bone disorders:
it allows a panoramic, low-cost and reproducible
evaluation of bone. More accurate analysis can be
obtained by means of CT, especially if complex anatomic areas must be examined. While CT allows an
optimal assessment of the bone cortex, MR imaging is the technique of choice to evaluate the bone
marrow. US has intrinsic limitations in the assessment of bone. In some applications, however, it can be
useful to assess selected bone disorders, especially if
performed as a complement to standard radiographs
(Cho et al. 2004). With US, the interface between soft
tissue and cortical bone is highly echogenic because
of an inherent high acoustic impedance mismatch
(Erickson 1997). The bone cortex appears as a regu-
lar continuous bright hyperechoic line with strong
posterior acoustic shadowing and some reverberation artifact (Fig. 5.2). Deeper structures, such as the
internal cortical architecture, the endosteum and
the underlying trabecular bone, remain inaccessible
with US, except for rare pathologic conditions in
which the cortex is extremely thinned or destroyed
in its full thickness. In normal adults, the periosteum cannot be detected as a separate structure with
US. Using very high frequency probes, it may appear
as a thin hypoechoic line apposed to the bone cortex
at certain sites in children.
Given the straight and continuous appearance
of the bright echo of the bony cortex, subtle surface
irregularities and sites of penetration of nutrient vessels can be visualized (Fig. 5.3). A careful scanning
technique and Doppler imaging allow easy depiction of the vessels entering the bone. The posterior
acoustic shadowing of sesamoids or calcifications
139
Bone and Joint
a
b
Fig. 5.2a,b. US appearance of normal bone: surface echotexture. a Longitudinal 12–5 MHz US image obtained over the diaphysis
of the radius with b radiographic correlation demonstrates the bone surface as a continuous straight hyperechoic line (arrows)
produced by a strong reflection of sound due to the marked difference in acoustic impedance of the soft tissues and bone.
Reverberation artifact (arrowheads) projecting in the shadow beyond the bone can be seen
Fig. 5.3a–c. US appearance of normal bone:
nutrient vessels. a,b
Longitudinal a gray-scale
and b color Doppler
12–5 MHz US images
over the diaphysis of the
ulna reveal a small break
(arrowhead) in the bone
surface crossed by nutrient vessels (arrow). This
finding should not be
mistaken for fractures or
erosions. c Radiographic
correlation demonstrates
a nutrient channel
(arrowheads) piercing
the ulnar shaft obliquely
a
b
c
located in close relationship with the bone surface
can mimic cortical breaks. Growth plates in the
immature skeleton may also resemble a focal discontinuity of the bone surface: they can be distinguished
from fractures due to their peculiar anatomic location (Fig. 5.4). Marginal osteophytes or bone spurs
can project over the cortex mimicking focal breaks.
Previous surgery may also affect the continuity of the
cortex. Focal interruptions of the hyperechoic corti-
cal line are seen after construction of bone tunnels,
such as in ligament reconstruction surgery or following ablation of screws and pins. Close correlation with
standard radiographs allows a definitive diagnosis in
nearly all the circumstances described above.
A variety of focal projections (tuberosities, ridges,
etc.) and defects (fossae, sulci) of bone modulate
the cortical surface; they are often associated with
tendon or ligament insertion (tuberosities, ridges)
141
Bone and Joint
*
Scaphoid
*
a
T
T
b
*
*
d
c
Fig. 5.5a–d. US appearance of normal bone: surface details. a Coronal 12–5 MHz US image obtained over the lateral aspect of
the scaphoid with b correlative anteroposterior radiograph of the radial wrist demonstrates a blunt focal projection of bone
(arrowhead) at its waist emerging from underneath the radial styloid (curved arrow) and separating the proximal articular
surface covered by hyaline cartilage (arrow) from the extra-articular portion of bone. Distally, note the scaphoid tubercle
(asterisk) in a deeper location. T, trapezius. The field-of-view of the US image is indicated by a dashed rectangle in b. c Coronal
reformatted CT-arthrographic image and d anteroposterior conventional arthrogram obtained after intra-articular injection
of contrast material within the radiocarpal joint show the relationship of the landmarks described above with the intra- and
extra-articular portions of the scaphoid surface
Soft-tissues
Bone
a
b
c
d
Fig. 5.6a–d. Bone surface abnormalities that are detectable with US. a Normal bone: a straight
regular interface separates the bone from the soft-tissues. b Outgrowths or “plus images”: a focal
projection of bone (arrows) is observed in the soft tissues. c Irregularities of the cortical outline:
the bone–soft tissue interface is rough (arrowheads); focal breaks (white arrow) or step-off deformities (black arrow) can be seen. d Defects or “minus images”: a focal loss of bone (arrows) is
observed. Soft tissues intervene within the defect
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M. P. Zamorani and M. Valle
lesions may be obscured by the curvature of bone and
overlying structures. These are the main reasons why
bone should invariably be checked during a standard
US examination of the musculoskeletal system. Bone
abnormalities seen at US can easily be correlated with
clinical findings and can suggest the requirement for
additional radiographic views or other imaging studies if further evaluation is warranted.
5.1.3
Outgrowths
5.1.3.1
Anatomic Variants
Plus lesions can be related to normal anatomic
variants that may become symptomatic because
of compression exerted on the adjacent soft-tissue
structures. The role of US in the assessment of bone
variants is twofold: to detect them and to reveal
associated pathologic changes in the adjacent soft
tissues. US is not only able to demonstrate the relationship between the abnormal bony outgrowth and
the surrounding soft tissues, but can also evaluate
tendon or nerve impingement during dynamic scanning. Among possible examples of bone outgrowths
that represent anatomic variants, the supracondylar
process is a rare bony outgrowth that arises from the
medial aspect of the distal humeral shaft (Sener et
al. 1998; Subasi et al. 2002). It can give rise to a thick
fibrous band (Struthers ligament) inserting into the
distal humeral epiphysis. Due to the close relationship with the median nerve, the process and the
adjacent ligament can cause a nerve entrapment syndrome (see Chapter 7). As described in Chapter 17,
the peroneal tubercle of the calcaneus is a small bone
ridge that gives insertion to the inferior peroneal
retinaculum and separates the peroneus brevis from
the peroneus longus tendons. Congenital enlargement of the tubercle appears at physical examination as a firm mass located just inferior to the tip of
the lateral malleolus. Chronic friction of a hypertrophied tubercle with the adjacent tendons can cause
stenosing tenosynovitis or tendon rupture (Bruce
et al. 1999; Wang et al. 2005).
5.1.3.2
Bone Exostoses
Bone exostoses (osteochondromas) are benign
tumors arising, in most instances, from the
metaphysis of long bones. They consist of a bony
spur whose cap is covered by hyaline cartilage.
Exostosis can be solitary or multiple, the latter
condition being known as multiple hereditary
exostosis (Murphey et al. 2000; Stieber and
Dormans 2005). Most solitary osteochondromas occur in the distal femur, proximal tibia and
proximal humerus. They may become symptomatic because of impingement on the adjacent softtissue structures, such as nerves, tendons and vessels (see Chapter 14) or, more rarely, because of
neoplastic changes (chondrosarcoma) occurring
in the cartilaginous cap. In other instances, exostoses may lead to formation of an inflamed synovial bursa as a result of chronic friction. US demonstrates exostoses as outgrowths of hyperechoic
bone covered by hypoechoic cartilage (Fig. 5.7).
The bone component of the exostosis appears as
a continuous hyperechoic line, whereas the cartilaginous cap consists of a hypoechoic layer that
may contain some hyperechoic foci with posterior
acoustic shadowing related to cartilage calcifications (Murphey et al. 2000). US has been shown
to allow accurate measurement of the cartilaginous cap thickness, a factor related to the risk
of sarcomatous degeneration (Malghem et al.
1992). The main limitations of US are its inability
to evaluate deep lesions inaccessible to the probe
and the analysis of the osseous component of the
lesion (Murphey et al. 2000). Local compression
exerted on the adjacent soft tissues can be diagnosed with US. Deep venous thrombosis, arterial
insufficiency and synovial bursa formation and
bursitis (bursa exostosica) are associated findings detectable with gray-scale US and Doppler
imaging (Fig. 5.8) (El-Khoury and Bassett 1979;
Keeling et al. 1993; de Matos et al. 1983).
5.1.4
Defects
US can detect a variety of “minus” lesions ranging from small para-articular erosions caused by
chronic synovitis to large post-traumatic defects.
One of the most common bone defects is the HillSachs lesion, a compressive fracture of the humeral
head that follows anterior shoulder dislocation
(see Chapter 6). The lesion derives from the traumatic action of the sharp anterior glenoid border
against the posterolateral aspect of the dislocated
humeral head. US has proved to be an efficient
modality to detect a Hill-Sachs lesion and assess
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Bone and Joint
implants can be followed by complications, such as
infection, impingement and mechanical failure. In
infections, US can identify soft-tissue abscesses
and sinus tracts, and assess their relationship with
implants and vital structures (Fig. 5.12a,b) (Gibbon
et al. 2002). In addition, US can be used to guide
needle aspiration of fluid collections for cultural
purposes. Recently, extensor pollicis longus tendon
tethering following K-wire insertion to treat unstable distal radius fractures has been described with
US (Harrison et al. 2004). After volar plate osteotomy for Colles fracture, tenosynovitis and tears
of this tendon following impingement on the screw
can be demonstrated with US as well (see Chapter
10). Ankle tendon impingement due to orthopaedic hardware has also been reported (Fig. 5.12c–e)
(Shetty et al. 2002). In children with percutaneous cross-pin fixation for displaced supracondylar
humeral fractures, dynamic US can evaluate altered
gliding and impingement of the ulnar nerve in the
cubital tunnel (Karakurt et al. 2005).
Some authors have suggested that the process of
fracture healing can be followed with color Doppler
imaging and spectral analysis (Caruso et al. 2000).
The rationale is based on the fact that, at the time of
trauma, the blood supply to the fracture site is inter-
*
*
a
b
*
ta
*
tibia
c
ta
*
tibia
d
Fig. 5.12a–e. Complications of orthopaedic treatment of fractures. Two different cases. a,b Transverse and b longitudinal 12–
5 MHz US images of the left femur in a patient who was previously treated for a femoral shaft fracture with placement of a
metal implant (open arrowheads) demonstrate a hypoechoic fluid collection (asterisks) surrounding the compression plate.
Subsequent surgery disclosed an abscess. Note the posterior reverberation artifact (white arrowhead) of the plate compared
with the femoral cortical bone (arrow). c Long- and d short-axis 17–5 MHz US images over the anterior cortex of the distal
tibia with e radiographic correlation in a patient previously operated on for a tibial fracture reveal the surface contours of an
interlocking screw head (arrow) impinging on the tibialis anterior tendon (ta). Reverberation (arrowhead) is shown deep relative to the screw head. Note the associated tenosynovitis (asterisks) of the tibialis anterior tendon
e
148
M. P. Zamorani and M. Valle
rupted; then, blood vessels reach the periosteal portion of the callus from adjacent soft tissues forming
a new circulation to the callus (Postacchini et al.
1995). US is able to follow the formation of new vessels at the fracture site and to assess flow characteristics in them during development of fracture callus
(Fig. 5.13a) (Caruso et al. 2000). In patients with
normal callus development, Doppler spectral analysis reveals an initial decrease in the resistive index
as a result of the neoangiogenetic process occurring
during the early weeks after fracture (Fig. 5.13b).
Over time, the arterial resistance progressively
increases, reflecting a physiologic decrease in the
degree of local vasculature that accompanies the
mature phase of the callus. On the other hand,
patients with non-union and delayed healing have
higher resistances early, related to a poor formation
of neovasculature. Although these features need
further experience in larger series, Doppler imaging
seems a promising modality for predicting normal
or delayed fracture healing based on defective vasculature at the fracture site about 1 month after
trauma (Caruso et al. 2000). However, standard
radiographs remain the primary imaging technique
for evaluating callus formation.
5.1.5.4
Erosions
In patients who have rheumatoid arthritis, US has
proved to be an excellent modality for detection of
a
early bone erosions, with a sensitivity superior even
to plain films (Wakefield et al. 2000). Erosions typically occur in the hand, the capitate being the bone
most commonly affected, followed by the triquetrum, hamate, scaphoid and trapezoid; the second
and third metacarpal heads are also a common
location (Cimmino et al. 2000). US demonstrates
erosions as oval or rounded well-defined cortical
breaks with an irregular floor visible in longitudinal
and transverse planes (Fig. 5.14a,b). They initially
affect the bare areas of the joint surface and share
a common appearance in rheumatoid arthritis and
other seronegative arthropathies. Hypoechoic synovial pannus and Doppler signals of flow are often
detectable within them. Loss of definition of the
articular cartilage and widening of the joint spaces
are associated findings. Compared with standard
radiographs, US can be considered a more sensitive,
effective and reliable means for detecting erosions
in rheumatoid arthritis (Wakefield et al. 2000;
Alarcon et al. 2002; Weidekamm et al. 2003). In
early disease, it has been shown able to detect 6.5fold more erosions than did radiography in 7.5-fold
the number of patients. In advanced disease, these
differences were 3.4-fold and 2.7-fold, respectively
(Wakefield et al. 2000). Depending on their location, US has proved to be superior to radiography
for depiction of erosions in the first, second and
fifth metacarpophalangeal joints, but inferior in the
fourth metacarpophalangeal joint due to the problem of access (Schmidt 2001). Erosions being most
commonly found along the radial and ulnar sides of
b
Fig. 5.13a,b. Early callus formation following fracture of the distal tibia. a Color Doppler 12–5 MHz US image obtained 12 days
after treatment shows a bone defect (arrowheads) related to the fracture site and multiple blood flow signals (arrow) in the
periosseous soft tissues superficial to the fracture. b Spectral analysis reveals low-resistance (RI <0.50) arterial flow in the vessels surrounding the fracture. These features indicate initial normal development of fracture callus
150
M. P. Zamorani and M. Valle
US cannot assess bone marrow and trabecular bone
involvement, but is an excellent means of identifying
abscess formation and adjacent soft-tissue involvement (Mah et al. 1994; Davidson et al. 2003). In
the pediatric age group, deep soft-tissue swelling
has been described as the earliest sign of disease
followed by periosteal elevation and formation of
a thin layer of subperiosteal fluid (see Chapter 19)
(Mah et al. 1994). At US, periosteal elevation can
be appreciated as single or multiple linear echoes
surrounding the cortical bone, whereas subperiosteal fluid appears as an anechoic or hypoechoic
collection separating the periosteum from the cortical bone as the result of superficial extension of
the intraosseous process (Fig. 5.15a) (Steiner and
Sprigg 1992; Sammak et al. 1999). Detection of
blood flow within or around the infected periosteum
demonstrated by Doppler imaging can be useful in
distinguishing early from advanced acute osteomyelitis (Chao et al. 1999). Doppler US has also been
found valuable in assessing the efficacy of antibiotic
therapy (Chao et al. 1999). One should be aware,
however, that a normal US examination does not
exclude bone infection (Bureau et al. 1999). Later
stages of disease are characterized by cortical irregularities and erosions, which are typically found in
patients with symptoms lasting for more than 1
week (Fig. 5.15b–e). Then, subperiosteal collections
may expand and form abscesses that can be drained
under US guidance when medical therapy alone is
inadequate (Abiri et al. 1989; Bureau et al. 1999;
Craig 1999). US guidance contributes to reducing
complications related to the procedure, such as the
inadvertent contamination of uninvolved compartments and traumatic damage to vessels and nerves
along the needle path (Bureau et al. 1999; Craig
1999). An opening (cloaca) connecting the infected
bone with the abscess or a channel between the
infected bone and the skin (sinus tract) can be seen
as a defect of the cortical layer in continuity with
the hypoechoic collection. Generally speaking, the
value of US appears even more relevant in the postoperative phase when the use of MR imaging may be
hampered by the presence of orthopaedic metallic
implants. In this instance, US can reveal the fluid
collection apposed to the implant, which appears
as a bright linear structure with posterior reverberation artifact surrounded by hypoechoic fluid.
Finally, it is important to point out that evaluation
of osseous involvement requires composite imaging algorithms for specific clinical scenarios, with
combined use of plain films, nuclear medicine, CT
and MR imaging (Sammak et al. 1999).
5.2
Joint
5.2.1
Histologic Considerations
Joint anatomy is variable depending on specific
functional requirements. Based on their anatomic structure, joints can be divided in three
main groups: fibrous, cartilaginous and synovial
(Erickson 1997). In fibrous joints, the bone ends
are linked by intervening solid connective tissue,
including a sutural ligament (sutures), a collagenous
interosseous ligament or membrane (syndesmoses)
or cartilaginous periodontium (gomphoses). Cartilaginous joints are divided into symphyses—which
contain a fibrocartilaginous disk—and synchondroses—which are formed by bony ends covered
by cartilage but lacking synovium. Synovial joints
are formed by adjacent bones connected by a cavity
lined by synovial membrane. The above types of
joints allow different degree of motion, which is
minimal in the first group (fibrous) and maximal
in the latter (synovial). Because synovial joints are
the most commonly examined with US, we will specifically discuss their normal anatomy.
Synovial joints are formed by articulating bone
surfaces, fibrous capsule and ligaments, synovium
and other intra-articular structures (menisci, labra,
ligaments, fat pads, etc.) (Fig. 5.17). The subchondral
bone plate is a thin layer of dense bone linked to the
cancellous and cortical bone of the metaphysis that
acts as a support for the articular cartilage. The main
function of bone plates is to adsorb part of the load
from the cartilage and transfer it to the cortical bone
through the metaphysis. The microstructure of subchondral bone, with its peculiar orientation of trabeculae, reflects this function. The articular surfaces
of bone are covered with hyaline cartilage (Fig. 5.16a).
The cartilage thickness varies among joints: thicker
cartilage is found in larger joints subjected to considerable loading, such as the weight-bearing joints of the
lower limb. The cartilage thickness also varies in different sites of the same joint as an expression of local
differences in load. The hyaline cartilage is formed
by cells—the chondrocytes, which account for 0.1%
of cartilage volume—and chondroid matrix consisting of collagen and proteoglycans. From the histologic point of view, four cartilage layers can be recognized from superficial to depth, based on a different
architecture and orientation of collagen fibers. In the
superficial layer, the collagen fibers run tangential
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intra-articular fibrocartilage structures (Fig. 5.17d). It
also invests some transitional zones extending from
the peripheral boundaries of the hyaline cartilage and
the fibrous capsule, the so-called bare areas. At these
sites, the bone is covered by synovium without the
protective layer of cartilage: this makes it particularly
vulnerable to synovitis-induced bone destruction
(Sommer et al. 2005). Different fibrocartilage structures can be found inside the joint space or related to
the articular capsule: their main function is to increase
the congruence of the articular surfaces by filling the
space between them and to act as shock absorbers thus
preventing damage to the hyaline cartilage (Fig. 5.17d).
Some joints contain fat pads, which are adipose struc-
tures filling the space between the synovial membrane
and the peripheral capsule (Fig. 5.17d). Intra-articular
fat pads adapt their shape to joint movements and the
amount of intra-articular synovial fluid; they absorb
forces generated during joint motion.
5.2.2
Normal US Anatomy and Scanning Technique
The indications for joint US are rapidly expanding
due to the refinement of high-resolution transducers and to the fact that both radiologists and clinicians are increasingly aware of the potential of US
a
b
Fig. 5.17a–d. General anatomy of synovial joints. Schematic drawings of a cross-sectional view of a synovial joint. a Joint
capsule and articular cartilage. The joint capsule (straight arrows) is a fibrous sac that inserts beyond the articular surfaces of
articulating bones. The thickness of the articular cartilage (asterisks) may vary among parts of the same joint depending on the
different demands of loading and weight-bearing (arrowheads). The cartilage transmits loading to the subchondral bone plate
(1) which, in turn, transfers part of it (curved arrows) to the cortical bone (3) through the metaphyseal region (2). b Synovial
recesses and sesamoids. The synovial recesses arise from focal discontinuities of the capsule, allowing the synovium to extrude
into the surrounding soft tissues. Synovial herniation may form communicating synovial pouches (1) or may link the joint
cavity with adjacent synovial tendon sheaths (2). Sesamoids (asterisk) are small ossicles embedded in the fibrous capsule or
the plantar plate. They can or cannot articulate with the joint surfaces. c Ligaments. These are fibrous bands formed by focal
thickening of the capsule (1) or lying at a certain distance from it (2). The strongest ligaments insert into para-articular bone
ridges or tubercles (3); these are appropriately oriented to counteract joint instability. d Synovium, fibrocartilages and fat pads.
The synovial membrane (thin arrow) invests the joint cavity with the exception of fibrocartilaginous structures (asterisk) and
intra-articular extrasynovial fat pads (thick arrow). Between the peripheral boundaries of the hyaline cartilage and the capsule,
the synovium invests the bone directly. These zones are called “bare areas” (curved arrow)
c
d
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M. P. Zamorani and M. Valle
a
b
LM
c
*
Talus
d
Fig. 5.20a–d. Normal ligaments. a–c Schematic drawings illustrate the relationship of a ligament (large straight arrows) with
the underlying joint structures, including the hyaline cartilage (thin straight arrow), the joint cavity (asterisk) and the synovial
membrane (s). The position of the fibrous capsule relative to the ligament may be variable: a internal (between the ligament and
the synovium, i.e., the lateral collateral ligament of the knee); b bending to it (i.e., the glenohumeral ligaments of the shoulder,
the anterior talofibular ligament of the ankle, the medial collateral ligament of the knee); c external (outside the ligament and the
synovium, i.e., the anterior cruciate ligament of the knee). d Long-axis 17–5 MHz US image over the lateral ankle demonstrates
the normal anterior talofibular ligament as a thick fibrillar band (arrowheads) joining the lateral malleolus (LM) and the talus.
The deep surface of the anterior talofibular ligament is merged with the ankle joint capsule. Note the joint fluid (asterisk) in
close contact with the ligament. Thin arrow, articular cartilage
Boutry et al. 2005). Somewhat similar to tendons,
ligaments are anisotropic structures. Therefore,
care should be taken to place the probe as parallel
as possible to them to avoid artifactual hypoechoic
patterns that can mimic pathology. Often, changing
the position of the joint improves ligament visualization. Small probes that can better hug the curves
and bulges of the bony landmarks are preferred for
imaging ligaments. Some ligaments located in the
central portion of joints (i.e., the interosseous tarsal
sinus ligaments and the cruciate ligaments of the
knee) cannot be visualized with US because of the
overlying osseous structures. Complex ligaments
(i.e., the medial collateral ligament of the knee, the
deltoid ligament of the ankle) are made up of individual components that can be distinguished with US
as individual structures. In general, ligaments that
stabilize a joint are best evaluated while stretched.
For example, in the relaxed state, the calcaneofibular ligament of the ankle has a concave course which
makes the evaluation of its cranial insertion difficult; with the ankle in dorsiflexion the ligament
tightens, pushing the peroneals superficially, and is
better depicted (Peetrons et al. 2004). Intra-articular fat pads appear at US as fat-like hyperechoic
structures (Fig. 5.18c). The most important are rec-
ognized in the knee (Hoffa pad) and the elbow (anterior and posterior fat pads) (Miles and Lamont
1989; Ferrara and Marcelis 1997). In most joints,
small amounts of normal intra-articular fluid can
be detected in the articular cavity by means of highresolution US.
5.2.3
Pathologic Changes
5.2.3.1
Joint Effusion
Demonstration of an intra-articular effusion is a
major step in the investigation of musculoskeletal disorders, as it points the clinician’s attention
toward a joint problem and excludes other extraarticular sources of pain and disability. A joint
effusion can derive from traumatic or mechanical
causes as well as from inflammatory or infectious
synovitis; more rarely, it can be related to neoplastic
conditions. At physical examination, detection of
synovial effusion depends on the overall amount
of fluid and the type of joint is involved. Accurate
palpation allows detection of medium to large effu-
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M. P. Zamorani and M. Valle
definite indication for sampling, analysis and cultural procedures in order to rule out microcrystal
arthritis and infection. For injecting small joints,
US guidance allows significantly greater accuracy
than a blind approach (Raza et al. 2003). In our
practice, US-guided aspiration of joint fluid significantly reduces the pain associated with needle
puncture. In addition, real-time monitoring of the
needle reduces the risk of potential damage to adjacent structures, including arteries and nerves. In
the traumatic setting, hemorrhagic joint effusions
may appear highly echogenic in the first few hours
after the trauma (Fig. 5.21c). Lipohemarthrosis is a
condition in which blood and bone marrow fat are
found inside the synovial cavity. While blood usually derives from tears of the synovial membrane, fat
comes from yellow bone marrow as a result of bone
fracture or, more rarely, from periligamentous fat.
In most cases, lipohemarthrosis can be considered a
confident indicator of an intra-articular fracture: it
is characterized by a multilayered appearance made
up of a superficial hyperechoic layer reflecting fat
and a deep hypoechoic layer due to sedimentation
of the red blood cells. After 10–15 minutes of joint
immobilization, a thin intermediate band due to the
serum can be noted between the fat and the red
blood cells (Fig. 5.21d,e) (Bianchi et al. 1995).
5.2.3.2
Rheumatoid Arthritis and Other Inflammatory
Arthropathies
US has been proposed for the early detection and
follow-up of several chronic inflammatory disorders of joints, including rheumatoid arthritis
(Wakefield et al. 2000; Keen et al. 2005; Scheel
et al. 2006; Gibbon 2004) and seronegative arthropathies (Gibbon 2004; Milosavljevic et al. 2005;
Kane 2005). Rheumatoid arthritis is a chronic systemic disease that affects approximately 0.5–1% of
the population and has a definite prevalence (2:1 to
3:1) in women. The etiology of rheumatoid arthritis is unknown but it seems to be multifactorial,
with any genetic susceptibility, expression of HLADR4 and environmental factors believed to play a
role (Sommer et al. 2005). The diagnosis requires
a spectrum of disease manifestations and can be
made according to established clinical criteria, the
description of which is, however, beyond the scope
of this chapter (Arnett et al. 1988; Sommer et al.
2005). From the pathophysiologic point of view,
synovial hyperemia is the first step of the inflam-
matory process in rheumatoid arthritis that can
be identified with diagnostic imaging modalities,
including power Doppler contrast-enhanced US
(Sommer et al. 2005). Then, the immune response
mediated by cytokines (TNFα and IL-1) and the subsequent infiltration by inflammatory cells lead to
edema and swelling of the synovium. This causes
widening of the joint space, which may be further
expanded by effusion (Fig. 5.22a). It is assumed
that the above stages of the disease may be fully
reversible. Later, the inflammatory response leads to
hypertrophy of the synovial membrane by invasive
granulation tissue with proliferation of synoviocytes, macrophages, lymphocytes, plasma cells and
mast cells. As synovial hypertrophy continues, the
hypertrophied synovium—usually referred to as
“pannus” (the Latin for “cloth”)—undergoes villous
transformation and expands concentrically into the
joint space leading to damage of the central portion of the articular cartilage and the subchondral
bone (formation of subchondral cysts and erosions)
(Fig. 5.22b). Tenosynovial sheath involvement coexists in many instances (see Chapter 3). From the
clinical point of view, the above abnormalities are
encountered not only in rheumatoid arthritis but
also in other forms of chronic arthritis. The hallmark of rheumatoid arthritis is bilateral symmetrical involvement of more than three joints. Early
in its course, the disease usually affects the small
hand joints, the second and third metacarpophalangeal and the third proximal interphalangeal joints
being the more typically affected (a characteristic
finding of rheumatoid arthritis is sparing of the
distal interphalangeal joints, which are commonly
involved in osteoarthritis and psoriatic arthritis). In
more advanced disease, synovitis involves the larger
joints of the limbs and extremities. The destructive
action of the pannus is responsible for progressive
joint surface damage, ligament and capsule tearing and, finally, joint instability and deformities
(Fig. 5.22c,d). When imaging rheumatoid arthritis,
one should consider that the disease progresses in a
nonlinear fashion and that joint involvement is nonuniform, particularly in the early stages. Although
a consensus has not been reached on which joints
must be systematically checked, the symptomatic ones and those typically involved in rheumatoid arthritis (i.e., wrist and hand joints) should
be examined (Sommer et al. 2005). For follow-up
purposes, wrist and hand joints are the preferred
sites for assessing the efficacy of therapy (Sommer
et al. 2005). In terms of treatment, among drugs
that have an influence on the course of disease are
Bone and Joint
a
b
c
d
Fig. 5.22a–d. Rheumatoid arthritis. Schematic drawings showing progression of joint damage during the course of disease. a
Early involvement is characterized by joint effusion and pannus formation (1) associated with marginal erosions (2), cartilage
thinning (3) and loosening of the capsuloligamentous structures (4). b As the disease progresses, the erosions increase in size,
subchondral cysts become evident (5) and the hyaline cartilage appears increasingly thinned (6). Partial tears of the paraarticular structures (7) may occur leading to joint instability. c Later on, fibrous ankylosis (9) of the joint can take place with
more evident destruction of the bone ends (10). d In some joints (carpal and tarsal joints) bone ankylosis (11) is the end stage.
Inactive fibrous pannus (12) may replace active erosive pannus in the chronic phase
the so-called biologic response modifiers (i.e., antiTNFα drugs) that inhibit certain cytokines, thus
reducing the inflammatory activity. These drugs are
expensive, have important side effects and must be
used in patients with erosive aggressive arthritis in
whom conventional drugs (NSAIDs, steroids, analgesics, etc.) do not produce a positive response. Early
diagnosis of synovitis is, therefore, required to start
adequate aggressive therapy before occurrence of
structural damage to the joint (Herburn 1988).
Because early changes in rheumatoid arthritis
are nonosseous in nature, US has proved superior to
conventional radiography in terms of disease detection (Gibbon 2004; Clement et al. 2005: Keen et
al. 2005). In patients with rheumatoid arthritis and
other seronegative arthropathies, US is an effective
means for detecting early signs of synovitis, thus
allowing prompt institution of an appropriate treatment (Grassi et al. 1993, 2001; Brown et al. 2004).
As stated before, US is able to detect joint effusion
–which accompanies acute inflammatory phases
or exacerbation of disease – even in small synovial
joints and can distinguish affected from adjacent
normal joints. It can define synovial changes, allowing evaluation of pannus as hypoechoic vegetations
protruding inside the synovial fluid or completely
filling the articular space (Fig. 5.23a,b). Using MR
imaging as the reference method, US has proved to
have higher sensitivity and accuracy in detecting
signs of inflammation in finger joints than do clinical and radiographic examinations, without loss
of specificity (Szkudlarek et al. 2006). In other
series, it was even more sensitive than MR imaging in detecting synovitis (Backhaus et al. 1999).
The integrated use of Doppler imaging can help to
distinguish hypervascular (active) from hypovascular (inactive) pannus, to monitor the response to
therapy based on a decreased hyperemia (reflecting improvement in terms of symptoms and disease
activity variables) and to differentiate active pannus
from echogenic effusion (Fig. 5.23c–f) (Spiegel et
al. 1987; Newman et al. 1996; Hau et al. 1999, 2002;
Backhaus et al. 1999; Stone et al. 2001; Szkudlarek
et al. 2001; Klauser et al. 2002; Fiocco et al. 2005;
Kiris et al. 2006). In addition, Doppler US may have
value in distinguishing noninflammatory synovial
proliferation in osteoarthritis from inflammatory
arthritis (Breidahl et al. 1996). Similar to gadolinium-enhanced MR imaging, some attempts have
been made with US to obtain a quantitative estimate of the synovial volume. Although a correlation among the histologic findings, clinical markers of disease activity and synovial volume seems to
exist, such measurements are time-consuming and,
therefore, not currently applicable in routine practice. More recently, microbubble-based US contrast
agents seem to be a promising adjunct to assess the
activity of the disease process (Magarelli et al.
2001; Klauser et al. 2002). There have been many
reports in the literature on power Doppler rather
than on color Doppler imaging to detect synovial
hyperemia. Current US technology indicates, however, that the sensitivity of color Doppler systems to
detect slow and low blood flow signals is now at least
equal to or even superior to that of power Doppler
imaging. The main limitations of both techniques
are essentially related to the lack of standardized
examination technique, reproducibility, operator
159
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Bone and Joint
experience and choice of the equipment (Cardinal
et al. 1996; Koski et al. 2006).
In advanced disease, the inflammatory process
may lead to massive erosions and extensive bone
damage with disintegration of structures of and
around joints, fibrosis, subluxation or dislocation
and, at the end stage, bone ankylosis. Based on
cartilage thickness measurements, US has proved
able to estimate the amount of cartilage destroyed
(Grassi et al. 1993; Grassi et al. 1999). US can also
depict joint space abnormalities at an earlier stage
than conventional radiography. A characteristic feature of rheumatoid arthritis is the release of a subset
of loose bodies, called “rice bodies,” within the joint
cavity (see Chapter 6). These particles are considered to be the result of sloughed fibrinogen-coated
infarcted synovial tissue or aggregates of fibrin,
fibronectin or multinuclear cells (McCarthy and
Cheung 1982; Popert 1985). US may demonstrate
rice bodies as hypoanechoic spherules measuring
a few millimeters in size (Martini et al. 2003). In
many instances, however, distinguishing them from
hypertrophied synovium with US may be difficult
(Fig. 5.24).
Among the seronegative (rheumatoid factor negative) arthropathies, US has proved useful to examine
patients with psoriatic arthritis (Kane et al. 1999;
Fiocco et al. 2005; Ory et al. 2005; Kane 2005). Like
rheumatoid arthritis, psoriatic arthritis is a chronic
disorder with significant joint damage at an early
stage of the disease process (Husted et al. 2001). The
distal interphalangeal joints are typically affected in
an asymmetric pattern. Characteristic radiographic
features include joint erosions, joint space narrowing,
bony proliferation including periarticular and shaft
periostitis, osteolysis with “pencil-in-cup” deformity
and acro-osteolysis, ankylosis, spur formation and
spondylitis. In psoriatic arthritis, synovitis, enthesitis and tenosynovitis can be reliably assessed with
US (Barozzi et al. 1998; Kane et al. 1999; Fiocco
et al. 2005; Ory et al. 2005; Kane 2005; Falsetti et
al. 2003). In general, the US findings are nonspecific
as they may also occur in patients with rheumatoid
arthritis and osteoarthritis (Fiocco et al. 2005; Ory
et al. 2005). In psoriatic dactylitis (sausage digit), US
may show subcutaneous soft-tissue enlargement and,
to a lesser extent, tenosynovitis and joint synovitis,
the latter sign correlating with joint space narrowing
and periostitis on plain films (Fig. 5.25) (Barozzi et
al. 1998; Kane et al. 1999). In seronegative arthropathies, unenhanced and contrast-enhanced color
Doppler imaging are able to demonstrate active sacroiliitis by showing a hypervascular pattern around
a
b
Fig. 5.24a,b. Rice bodies in rheumatoid arthritis. a Longitudinal 12–5 MHz US image over the anterior knee shows a distended
suprapatellar recess (arrows) filled with heterogeneous solid tissue resembling synovial pannus. b Corresponding sagittal T2weighted MR image reveals multiple hypoechoic dots (arrowheads) in the fluid related to rice bodies. The US appearance of
rice bodies may be virtually indistinguishable from synovial pannus
162
M. P. Zamorani and M. Valle
*
MPh
*
PPh
Fig. 5.25. Psoriatic dactylitis. Longitudinal 17–5 MHz US image over the proximal interphalangeal joint of the middle finger in
a 45-year-old woman with psoriatic arthritis shows extensive destruction of the articular surface (arrowheads) of the middle
phalanx (MPh). Coexisting deformity (arrow) of the head of the proximal phalanx (PPh) and heterogeneous appearance of
para-articular soft-tissues (asterisks) is found. The findings correspond to the radiographic sign referred to as the “pencil-incup” deformity
the posterior aspect of the sacroiliac joints (Arslan
et al. 1999; Klauser et al. 2005). In ankylosing spondylitis, there is predominant involvement of large
joints, such as the knee, the shoulder and the hip,
with uniform joint space narrowing and low-grade
subchondral sclerosis and synovitis. Reiter arthritis
is characterized by prevalent distal lower extremity
involvement and conspicuous new bone deposition.
Arthritis in inflammatory bowel disease is, for the
most part, transitory and not destructive; the most
commonly involved joints are the knee and the ankle.
The features of juvenile idiopathic arthritis are discussed in detail elsewhere (see Chapter 19).
5.2.3.3
Septic Arthritis
Septic arthritis is a serious condition leading to
rapidly destructive joint disease (Goldenberg
1998; Mohana-Borges et al. 2004). This condition is most commonly caused by Staphylococcus
aureus (in adults and children older than 2 years)
and Neisseria gonorrheae (in young adults), which
have a definite tropism for the synovium (Craig
et al. 2003; Mohana-Borges et al. 2004). A variety of streptococci, including S. viridans and S.
pneumoniae, group B, aerobic Gram-negative rods,
viruses, mycobacteria and fungi may also produce
joint infection in isolation or as a result of polymicrobial association (Jbara et al. 2006). Possible
pathomechanisms of infection are: hematogenous
seeding of the synovium from a distant focus or an
adjacent area of osteomyelitis; spread from a contiguous infected site, such as the soft tissues in the
diabetic foot; and inadvertent implantation during
arthrocentesis or secondary to penetrating wounds
and postoperative infection (Mohana-Borges et
al. 2004). The most common pattern of presentation of septic arthritis is monoarticular. The most
commonly involved joints are the hip, the knee,
the shoulder, the elbow and the ankle (MohanaBorges et al. 2004; Chau and Griffith 2005).
Infection causes lysis of the articular cartilage,
joint space narrowing and periarticular osteopenia.
Late complications of arthritis include joint subluxation, premature osteoarthritis, osteonecrosis,
fibrous or bony ankylosis, and limb shortening. In
the acute setting, US is a reliable way to detect early
septic arthritis before the occurrence of substantial cartilage lysis and when radiographs are still
noncontributory (Bureau et al. 1999). The main US
sign of septic arthritis is detection of a joint effusion in a patient with clinical signs of joint infection (pain, redness, heat, soft-tissue swelling about
the involved joint). As regards fluid echotexture,
septic effusions often contain a diffuse pattern of
low-level echoes and are clearly demarcated from
the thickened synovial walls (Chau and Griffith
2005). Highly hyperechoic effusions with debris
and septations are often encountered. This appearance might confuse the inexperienced examiner as
the collection appears to be solid on static scans;
however, dynamic examination and probe com-
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Bone and Joint
pression may show swirling of echoes indicating
fluid (Fig. 5.26). Gas bubbles may also be found
in joint infection. On the other hand, completely
anechoic collections of infected joint fluid are
rare. However, these characteristics are too subtle
to allow a definitive diagnosis and needle aspiration of fluid, possibly obtained under US guidance,
is needed to confirm the infectious nature of the
effusion (Bureau et al. 1999; Widman et al. 2001).
Power Doppler imaging almost invariably shows a
synovial hyperemic flow pattern of hypertrophied
synovium and para-articular tissues. Even though
the absence of fluid in a joint does not exclude
adjacent osteomyelitis, a negative US and Doppler
imaging examination makes diagnosis of septic
arthritis unlikely (Zawin et al. 1993).
5.2.3.4
Traumatic Injuries
When affecting joint portions that are amenable to
US examination, osteochondrosis and osteochondral fractures can be detected as surface irregularities of the cartilage or nidus formation involving the
cartilage and the subchondral bone (Takahara et
al. 1988). In degenerative osteoarthritis, the cartilage
may appear progressively thinner and irregular, or
even completely disintegrated, whereas the hyperechoic line of the subchondral bone shows irregularities. At US, osteophytes are usually depicted at the
joint margins as beak-shaped hyperechoic bone projections covered by cartilage. Following joint surface
fractures or other conditions leading to progressive
Patella
F
e
T
b
Fem
e
a
c
Fig. 5.26a–c. Septic arthritis. a Lateral radiograph of the knee in a newborn with fever and painful swollen knee suggesting an
infection reveals diffuse soft-tissue swelling and an enlarged knee joint space. b,c Longitudinal 12–5 MHz US images obtained
over b the patella and c the suprapatellar recess demonstrate the joint cavity filled with highly echogenic dense fluid (arrows)
related to purulent material and debris. Note the hypoechoic appearance of the unossified patella and the epiphyseal cartilages of the femur (F) and tibia (T). e, ossification center of the distal femoral epiphysis. Aspiration of the joint fluid revealed
Staphylococcus aureus infection
164
M. P. Zamorani and M. Valle
derangement of joints (i.e., osteoarthritis, osteochondromatosis, neuropathic joint disease), loose
bodies can be released into the joint cavity, possibly
leading to intermittent locking of the joint and early
degenerative changes. Intra-articular loose bodies
are osseous, chondral or osteochondral fragments.
They often have a three-layered structure composed
of a superficial bright echo due to an artifact at
the interface with fluid, an intermediate hypoechoic
band due to the cartilage, and a deep hypoechoic
surface with posterior acoustic shadowing due to the
bone component (Bianchi and Martinoli 2000).
In many instances, US can give a better delineation of loose bodies than can plain films and MR
1
2
*
imaging (Fig. 5.27). On the other hand, MR imaging is superior in detecting the nidus of the fragment. A monolaminar appearance is observed in
old extensively calcified fragments, which appear
as hyperechoic images like gallstones without a
detectable rim of hypoechoic cartilage (Bianchi
and Martinoli 2000). During joint motion or while
applying transducer pressure, loose bodies can be
mobilized within joint recesses: this may be helpful
for the differential diagnosis with either osteophytes
or capsular and synovial calcifications.
The diagnosis of joint instability basically relies
on plain films. In some instances, however, the complex anatomy of joints and surrounding structures
Qt
3
c
a
Qt
*
1
2
3
*
b
d
Fig. 5.27a–d. Osteochondral fracture. a Longitudinal and b transverse 17–5 MHz US images of the anterior knee in a patient with
onset of painful swelling and locking of the knee following an episode of patellar dislocation show a distended suprapatellar
recess (asterisks) containing an osteochondral loose body (arrowhead). The fragment is characterized by a trilayered structure
composed of: a superficial bright echo (1) due to the acoustic impedance mismatch at the solid-fluid interface; an intermediate
hypoechoic layer (2) due to the cartilage; and a deep bright echogenic surface (3) with slight posterior attenuation due to the
detached subchondral bone. c Lateral radiograph is unable to reveal the loose body except for a subtle radio-opaque linear
image (arrows) reflecting its bony component. Qt, quadriceps tendon. d Gross operative view demonstrates the loose body
(arrowhead) fixed into the patellar nidus
Bone and Joint
may make detection of subluxation and dislocation
of joints difficult on standard radiographs. If undetected, joint instability may lead to chronic local
pain, secondary osteoarthritis and altered joint
function. In specific clinical settings in which the
physical examination may be inconclusive, US can
contribute to the detection of occult positional joint
abnormalities, including posterior shoulder dislocation and mild acromioclavicular joint instability
(see Chapter 6) (Hunter et al. 1998; Bianchi et al.
1994; Bize et al. 2004; Borsa et al. 2005).
Many joints contain fibrocartilaginous structures, including the meniscus in the knee, the
labrum in the hip and the shoulder, the triangular
fibrocartilage in the wrist, and the volar and plantar
plates in the hand and foot. Because of their deep
location and close contact with the bone, these structures can be evaluated with US only in part and not
reliably. Although different authors have reported
a high sensitivity and specificity of US in diagnosing knee meniscal and shoulder labral tears (Sohn
et al. 1987a, b; Schydlowsky et al. 1998; Hammar
et al. 2001), further evidence has demonstrated that
US cannot be considered an accurate technique
for diagnosing fibrocartilage tears (Azzoni and
Cabitza 2002). In particular, distinguishing tears
from degenerative states is problematic on the basis
of the US findings due to a similar echotextural pattern. However, some conditions involving the superficial part of these structures, such as an extruded
meniscus, a meniscocapsular detachment with fluid
intervening between the capsule and the fibrocartilage or a meniscal ossicle can be inferred on US (see
Chapter 14). Initial experience is also available in the
literature on US investigation of the normal triangular fibrocartilage of the wrist and the volar plates
(see Chapters 10, 11) (Boutry et al. 2004; Chiou et
al. 1988; Keogh et al. 2004). However, further studies are needed to establish the ultimate value of US
in imaging pathologic conditions affecting these
structures. In contrast to the results of fibrocartilage
evaluation, US has proved to be an effective modality for diagnosing parameniscal (see Chapter 14) and
paralabral (see Chapters 6, 12) cysts (Peetrons et al.
1990; Rutten et al. 1998; Seymour and Lloyd 1998).
These cysts are believed to derive from tangential or
compressive forces that lead to trauma, degeneration and tearing of the fibrocartilage. Synovial fluid
is extruded through the tear toward the peripheral
margin of the fibrocartilage, expanding it and displacing the capsule outward into the surrounding
tissues (McCarthy and McNally 2004). Because
these cysts are almost invariably associated with a
fibrocartilage tear, the US diagnosis of an associated
meniscal or labral rupture is straightforward even in
cases of unclear or doubtful findings (Fig. 5.28a,b).
The cyst can track some distance from the fibrocartilage before becoming clinically palpable and
US may show a narrow pedicle connecting it to the
tear. Parameniscal and paralabral cysts appear as
space-occupying masses with sharply defined borders. They often exhibit mixed internal echotexture as a result of mucoid degeneration or appear as
undefined softening and swelling of the connective
spaces in which they expand (Fig. 5.28c,d). Even if
small in size, labral-related cysts may lead to neuropathy of adjacent nerves, such as the suprascapular nerve (posterior glenoid labrum cysts), the axillary nerve (inferior glenoid labrum cysts) and the
femoral nerve (anterior acetabular labrum cysts)
(see Chapters 6, 12) (Takagishi et al. 1991).
Ligament tears can be demonstrated with US at different sites, including the ankle and foot (Campbell
et al. 1994; Peetrons et al. 2004), the wrist and hand
(Jones et al. 2000; Noszian et al. 1995; Finlay et
al. 2004; Boutry et al. 2005), the knee (Ptasznik et
al. 1995; Miller 2002; O’Reilly et al. 2003) and the
elbow (Nazarian et al. 2003). The US features of a
torn ligament vary depending on whether the lesion
is acute or has healed. In acute phases, a partially
torn ligament appears swollen and hypoechoic but
continuous (Fig. 5.29a); an anechoic band over the
superficial aspect of the ligament may be observed
representing reactive soft-tissue edema (Peetrons
et al. 2004). In complex ligaments, US can distinguish the abnormal hypoechoic portion of the ligament from the unaffected one retaining a normal
appearance (Fig. 5.29b). In acute complete ruptures,
a hypoechoic cleft reflecting the hematoma can be
detected through the ligament substance and the free
ends of the severed ligament may appear retracted
and wavy (Fig. 5.30a,b). In doubtful cases, the ability to assess the ligament dynamically is a definite
advantage of US: under stress, a normal ligament
tightens preventing excessive widening of the joint
space; if the ligament is torn, a paradoxical movement is obtained reflecting joint instability (Fig. 5.30)
(De Smet et al. 2002; Brasseur et al. 2005). In
chronic partial tears, the ligament always appears
thicker than normal on US images. Calcifications
within the ligament substance in old tears and irregularities of the bony insertions in avulsion injuries
may be observed (Fig. 5.31) (Brasseur et al. 2005).
A typical example is the Pellegrini-Stieda syndrome
(calcification of the proximal end of the medial collateral ligament of the knee) (see Chapter 14). In liga-
165
167
Bone and Joint
*
LM
Talus
a
MC
*
Tibia
b
Fig. 5.29a,b. Partial ligament tear. a Long-axis 17–5 MHz US image over the anterior talofibular
ligament (arrowheads) in a patient following an inversion injury of the ankle demonstrates a markedly thickened and hypoechoic but straight ligament without signs of macroscopic discontinuity. A
hypoechoic band of fluid (asterisk) underlines the superficial aspect of the ligament representing
reactive soft-tissue edema. LM, lateral malleolus. Arrow, articular cartilage of the talus. b Coronal
17–5 MHz US image over the medial aspect of the medial femoral condyle (MC) reveals diffuse
hypoechoic thickening of the superficial component (arrows) of the proximal medial collateral
ligament, whereas the deep meniscofemoral component (arrowheads) is unaffected. Asterisk,
medial meniscus
underlying bone and at the joint margins (Felson
2004; Gupta et al. 2004). Osteoarthritis is the most
widespread form of joint disease in the Western
world and can be divided into idiopathic and secondary forms (Gupta et al. 2004). The causes of
osteoarthritis include various combinations of
systemic risk factors (aging, inheritance, estrogen
deficiency), local joint vulnerabilities (previous
injuries, bone malalignment) and extrinsic factors acting on the joint (obesity, muscle weakness,
occupational and sports-related repetitive overuse
but also chronic underuse) (Felson et al. 2004).
The initial abnormality of osteoarthritis occurs
in the articular cartilage with edema followed by
fibrillation and superficial and deep clefts possi-
bly evolving toward ulcerations and production of
new cartilage and bone. In severe forms, complete
cartilage loss associated with pathologic changes
of the subchondral bone (i.e., sclerosis, cysts) and
marginal osteophytes can occur. Intra-articular
loose bodies may develop as a result of detachment
of small cartilage pieces or bone fragments which
may activate new chondral or bone formation. The
diagnosis of osteoarthritis is essentially based on
clinical and radiographic data. US is able to detect
joint surface and hyaline cartilage abnormalities
(Grassi et al. 2005). Changes include progressive
thinning and irregularity of the cartilage layer up to
its complete disintegration and irregularities of the
underlying subchondral bone (Fig. 5.32) (Grassi et
168
M. P. Zamorani and M. Valle
1
LM
*
1
2
Talus
c
a
b
d
Lun
e
*
2
*
Lun
Scaph
f
Scaph
g
Fig. 5.30a–g. Complete ligament rupture. Spectrum of US appearances in a–d the anterior talofibular and e-g scapholunate ligaments. a Long-axis 17–5 MHz US image obtained at rest over the anterior talofibular ligament after an inversion injury with b
schematic drawing correlation demonstrates the torn ends (1, 2) of the ligament in a wavy shape with hematoma insinuating
between them. c,d While performing an anterior drawer test, there is opening (large arrows) of the joint space (asterisks) and
the ligament ends are more clearly separated from each other. e Transverse 17–5 MHz US image over the dorsal aspect of the
proximal carpal row shows a normal scapholunate ligament (arrows) joining the lunate (Lun) and the scaphoid (Scaph). f,g
Transverse 17–5 MHz US images obtained in patient who underwent previous wrist injury. f In neutral position, there is absence
of the scapholunate ligament with respect to the normal findings shown in e. The dashed lines demarcate the distance between
the scaphoid and the lunate. g During ulnar deviation of the wrist, widening (arrows) of the scapholunate distance can be seen:
this can be considered a sign of ligament tear
al. 1999). One of the major limitations of US in
evaluating osteoarthritis is the incomplete evaluation of the cartilage surface, which is, for the most
part, masked by the ends of opposing bones. This
is true for both tight and large joints. In the knee,
for instance, articular cartilages that are vulnerable
to tears and ulcerations are mainly located at the
posteroinferior aspect of the femoral condyle and
on the lateral facet of the patella: both surfaces are
barely evaluated with US. Similarly, geodes (subchondral cysts) are not visible at US because they
are completely surrounded by bone. On the other
hand, osteophytes can be readily appreciated as
beak-like bone projections covered by hypoechoic
cartilage adjacent to the joint line (Fig. 5.33). They
increase the surface area of the articular cartilage,
thus lessening the stress and loading forces that
are experienced by the joint and, at the same time,
increasing its stability: typical locations of osteophytes are the posterior humeral head, the internal femorotibial and the anterior tibiotalar joints
(Gupta et al. 2004). Finally, US can be useful in
assessing para-articular soft-tissue abnormalities
that can be responsible for pain in osteoarthritis
and may help to guide intra-articular drug injection
(Naredo et al. 2005; Migliore et al. 2005).
Bone and Joint
molecule – a step that would enhance amyloid formation – and in the generation of pain, dysfunction and
even destructive arthropathy (Bancroft et al. 2004).
In its articular form, amyloidosis most often involves
the hip, the knee and the wrist leading to development
of large amyloid-filled subchondral cysts in the juxtaarticular bone. The thickness of abnormal soft-tissue
material measured with US in the anterior recess of
the hip and the suprapatellar recess of the knee has
been found to correlate positively with dialysis duration and radiological and histologic evidence of amyloidosis (Jadoul et al. 1993). Based on echotextural
findings, amyloid deposits cannot be distinguished
from other synovial pathology (Fig. 5.35a,b). MR
imaging demonstrates amyloid with low to intermediate signal on T1- and T2-weighted sequences
(Fig. 5.35c,d) (Cobby et al. 1991).
5.2.3.7
Postoperative Complications
Detection and localization of postoperative infection
may be a challenging task. Septic arthritis complicating hip and knee joint replacement procedures is an
important risk factor reported to involve approximately 2% of cases (Goldenberg 1998). Based on
the clinical and radiographic findings, it may be
impossible to distinguish mechanical loosening of
a prosthesis from septic loosening (Bureau et al.
1999). Nuclear medicine, CT and MR imaging can be
impaired around orthopaedic hardware by metallic
shielding and artifact. US is less hindered in many
of these respects and can be considered the firstline diagnostic modality in this setting, provided
that an adequate probe access is available (Chau
and Griffith 2005). In the postoperative hip, infection can be suspected with US by the presence of
a large joint effusion (mean bone-to-pseudocapsule
distance: normal, 3.2 mm; infected, 10.2 mm) associated with an extracapsular noncommunicating
soft-tissue fluid collection and local inflammatory
changes (see Chapter 12) (van Holsbeeck et al.
1994). More recently, however, a retrospective study
revealed some limitations of US as an indicator of
adult hip joint effusion, even in the postoperative
setting (Weybright et al. 2003). When a collection is
present around a postoperative hip, US can effectively
guide arthrocentesis to obtain material for Gram
staining and bacterial culture (van Holsbeeck et al.
1994; Gibbon et al. 2002). Doppler US may also be
used to rule out deep vein thrombosis after total hip
or knee arthroplasty, especially if routine periopera-
tive pharmacologic antithrombotic prophylaxis is not
practised (Ko et al. 2003).
Granulomatous synovitis can be seen as a result
of reaction to small particles of silicone polymers or
other synthetic components of prostheses secondary
to shedding, so-called “silastic synovitis” or “detritic synovitis”. Often encountered in wrist implants,
this condition derives from a kind of foreign-body
response, in which activated macrophages provoke
bone resorption and dissection around the implant
(Bancroft et al. 2004). Standard radiographs show
well-defined subchondral lucency and erosions usually associated with fracture and/or dislocation of
the prosthesis (Rosenthal et al. 1983; Schneider
et al. 1987). MR imaging confirms the radiographic
findings and demonstrates multiple small hypointense particles that represent silicone fragments
resulting from implant breakage and disintegration
(Chan et al. 1998). US can demonstrate the implantderived debris as hyperechoic spots embedded
within hypertrophied synovium: these fragments
should be differentiated from calcifications based
on the presence of posterior reverberation and ringdown artifact (Fig. 5.36).
5.3
Space-Occupying Masses
5.3.1
Bone Tumors
The role of US for the detection and assessment of
bone tumors is obviously poor, given its inability to
define intraosseous processes. US can only detect
lesions associated with considerable cortical thinning and/or large extraosseous spread, such as large
tumors eroding the cortex (Saifuddin et al. 1998).
While evaluating bone tumors, US can be useful
in two main clinical situations: the detection of
an otherwise unsuspected tumor, or as guidance
for a percutaneous biopsy of a bone tumor already
investigated with standard radiographs, CT and MR
imaging. It is not uncommon for patients with a bone
tumor, either primary or metastatic, to complain of
nonspecific regional pain and to undergo US examination for a suspected soft-tissue abnormality before
a radiographic study. Therefore, careful assessment
of the bone surface must be part of a standard US
examination of soft tissues and the US signs suggesting a possible abnormality of bone – even if minimal
– must be known by the examiner.
173
175
Bone and Joint
In osteolytic tumors with extraosseous extension, US shows a periosseous soft-tissue mass arising from a break or a deep defect in the hyperechoic
bony cortex (Fig. 5.37). Direct continuity of the
mass from the inner bone into adjacent soft tissues
is a sign of the intraosseous origin of the tumor.
Although US has limitations in assessing infiltration of periosseous tissue planes, the boundaries
of the extraosseous component of the neoplasm are
usually well circumscribed. In general, the tumor
echotexture ranges from solid hypoechoic to a
mixed heterogeneous appearance due to internal
anechoic areas related to necrosis. In most cases, US
is unable to suggest the histologic diagnosis as well
as to differentiate malignant from locally aggressive
benign tumors. Based on their fluid-filled appearance, US can diagnose intraosseous ganglia extruding into the paraosseous soft tissues (Bianchi et al.
1995). Occasionally, a presumptive diagnosis can
be made, such as in the case of aneurysmal bone
cysts presenting marked cortical thinning and multiple fluid-fluid levels (Fig. 5.38) (Haber et al. 1993;
Gomez et al. 1998). In these instances, changing the
patient’s positioning can show respective changes
in the disposition of fluid layers within the tumor
compartments (Fig. 5.38a-d). Recently, the US
appearance of osteoid osteoma located in the proximal metaphysis of the right tibia and left femoral
diaphysis of adolescents has been described (GilSanchez et al. 1999). Color Doppler imaging may
be useful for detection of the hypervascular nidus
and to guide percutaneous localization and biopsy.
Doppler imaging should always be performed when
evaluating soft-tissue tumors. It can show internal
vasculature, thus helping to differentiate viable from
necrotic tissue. When a bone tumor exhibits a large
extraosseous component at MR imaging, US can be
effective and reliable to guide percutaneous needle
biopsy (Civardi et al. 1994; Saifuddin et al. 1998,
2000; Konermann et al. 2000; Yeow et al. 2000; GilSanchez et al. 2001; Torriani et al. 2002). Biopsy is
a fundamental step in the investigation of suspected
bone tumors and must be obtained in specialized
centers to avoid inadequate tissue sampling, which
is the most common reason for the inability to perform limb-salvage surgery (Skrzynski et al. 1996;
Saifuddin et al. 2000). US-guided biopsy must be
performed only in patients in whom the feasibility
of the procedure has been previously checked on
MR imaging or CT scan. The biopsy of a bone tumor
must be performed in agreement with the referring
orthopaedic surgeon in order to decide the most
*
b
Tibia
*
a
c
Fig. 5.37a–c. Bone tumors. Two different cases. a Extended field-of-view 12–5 MHz US image over a slow-growing palpable
pretibial mass in a patient with breast cancer shows a large well-circumscribed solid neoplasm causing osteolysis (straight
arrows) and extending into the adjacent extraosseous spaces (white arrowheads). Dashed line indicates the level of destroyed
tibial cortex. Residual small bone fragments (curved arrows) displaced by the growing neoplasm are seen. Biopsy revealed breast
metastasis. b Longitudinal 12–5 MHz US image obtained over the shoulder in a patient with suspected rotator cuff disease
reveals a large hypoechoic mass (asterisk) causing extensive osteolysis (white arrows) of the acromion (black arrow): some bone
fragments are visible within the mass (arrowhead). c Anteroposterior radiograph confirms the osteolytic lesion (asterisk) and
an associated pathologic fracture (black arrowhead). Biopsy revealed metastasis from lung cancer
176
M. P. Zamorani and M. Valle
a
c
e
b
d
g
f
Fig. 5.38a–g. Aneurysmal bone cyst in a 12-year-old boy with a stiff slow-growing painless swelling over the fibular head and
neck. a,b Coronal 12–5 MHz US images obtained over the fibular head a with the patient supine and b standing reveal a complex mass (arrows) which creates a bulge on the surface of the bone with cortical thinning (arrowheads) sufficient to allow
US beam penetration. The mass is characterized by multiple dual fluid levels, an appearance fairly specific for an aneurysmal
bone cyst. When the patient’s position is changed, fluid levels rearrange parallel to the floor according to gravity. c,d Diagrams
show the disposition of fluid levels as seen in a and b. e Photograph shows focal bulging (curved arrow) over the fibular head.
f Anteroposterior radiograph and g transverse T2-weighted MR imaging confirm the US diagnosis
appropriate needle path by consensus: this helps to
avoid seeding of tumor cells out of the involved compartment. As described in Chapter 18, 14–18 gauge
Tru-cut type automatic devices are recommended to
achieve better diagnostic yield for histologic diagnosis. Fine-needle aspiration biopsy seems to have
definite limitations in this field, even in detection
of tumor recurrence or diagnosis of metastasis of
a known primary tumor. Compared with CT guidance, the main advantages of US-guided biopsies
of bone tumors rely on the ability of US: to recognize viable tumor and adjacent vessels with Doppler
imaging; to allow continuous real-time visualization of the needle to avoid necrotic areas and the
risk of injury to adjacent structures; and to perform
the procedure more rapidly, reducing patient discomfort (Torriani et al. 2002). If the US biopsy is
performed in experienced hands, complications are
rare (Torriani et al. 2002). In rib lesions, local pain
and hematoma, infection and pneumothorax have
been reported as complications.
5.3.2
Pigmented Villonodular Synovitis
Pigmented villonodular synovitis is an uncommon
benign proliferative disease of the synovium that
affects joints, bursae or tendon sheaths (Dorwart
et al. 1984; Yang et al. 1998; Bianchi et al. 1998; Lin
et al. 1999; Middleton et al. 2004). From the pathogenetic point of view, the etiology of pigmented villonodular synovitis remains controversial. Of the
two most widely accepted theories, one implicates
a chronic inflammatory process, the other a benign
neoplasm (Byers et al. 1968; Mukhopadhyay et al.
Bone and Joint
2006). The presence of histiocytes that contain fat or
hemosiderin (a breakdown product of hemoglobin),
multinucleated giant cells and plasma cells seems
suggestive of inflammation, whereas the high cellularity, tendency for recurrence and recent cytogenetic studies revealing clonal cell proliferation favor
a neoplastic process (Mukhopadhyay et al. 2006).
The clinical presentation of articular pigmented
villonodular synovitis depends on the morphologic
form of disease, including a diffuse and nodular
type. The more common diffuse pigmented villonodular synovitis grossly appears as a widespread
proliferation of the synovium that shows fingerslike masses and villosities. It usually occurs in the
third and fourth decades of life as a monoarticular arthritis affecting the knee (80% of cases) (see
Chapter 14), the hip and the ankle. Patients’ complaints include insidious onset of progressive joint
swelling, discomfort, pain, mechanical derangement
and decreased range of motion. Focal pigmented
villonodular synovitis more frequently occurs in the
fifth and sixth decades, affecting joint, para-articular
bursae and synovial tendon sheaths (giant cell tumor
of tendon sheath), the latter being more common. It
has a female predominance and affects the digits of
the hand and foot, presenting as a slow-growing painless mass (Rao and Vigorita 1984).
Plain radiographs can be normal or show intraarticular effusion, an ill-defined para-articular
soft-tissue mass and, in longstanding disease, juxtaarticular bone erosions and subchondral cysts caused
by pressure and hypertrophied synovium. CT shows
hemosiderin and fat deposits, and is able to detect
bone erosions that are not manifest on radiographs.
MR imaging shows synovial effusion and hypertrophied synovitis containing scattered areas of hemosiderin that exhibits low signal intensity on T1- and
T2-weighted sequences—darker on T2* gradient-echo
sequences due to susceptibility artifact (Fig. 5.39).
Although similar appearances can be observed in
hemophilic and rheumatoid arthritis in the proper
clinical setting, these findings are often considered
to be diagnostic of pigmented villonodular synovitis
(Hughes et al. 1995; Jelinek et al. 1989; Narváez et
al. 2001). The US appearance of diffuse pigmented
villonodular synovitis is nonspecific as it appears
either as an intra-articular area of hypoechoic synovial thickening or as an irregular mass located within
the joint cavity usually associated with a joint effusion
(Fig. 5.39a). In some cases, US can detect pressure erosions on the bone cortex as defects of the joint surfaces filled with hypertrophied synovium. Doppler
imaging can show a hypervascular pattern within the
synovial mass (Yang et al. 1998; Lin et al. 1999). A
pattern of relatively increased flow in the periphery of
the synovial capsule may be present (Lin et al. 1999).
Local recurrence after surgical or arthroscopic synovectomy takes place in almost 50% of cases (Sheldon
et al. 2005). The nodular type of pigmented villonodular synovitis has been already described in Chapter 3
(Bianchi et al. 1998; Middleton et al. 2004).
5.3.3
Lipoma Arborescens
Lipoma arborescens, also referred to as diffuse synovial lipoma or villous proliferation of synovium, is
P
Femur
a
b
c
Fig. 5.39a–c. Pigmented villonodular synovitis: diffuse type. a Longitudinal 12–5 MHz US image obtained over the suprapatellar
recess demonstrates hypoechoic thickening of the synovium (arrowheads), a fairly nonspecific appearance. P, patella. b Sagittal
T2-weighted and c fat-suppressed postcontrast T1-weighted MR images confirm the US finding (arrowhead) and reveal additional lesions (arrows) lying in the anterior and posterior joint recesses. The hypointense pattern of these lesions on T2-weighted
sequences strongly suggests pigmented villonodular synovitis
177
Bone and Joint
a
b
a
c
d
b
c
Fig. 5.41a–d. Synovial chondromatosis. a Plain lateral radiograph of the index finger shows a small soft-tissue calcified mass
on the volar (white arrow) aspect of the first phalanx. Some calcifications are also visible on the dorsal aspect of the proximal
phalangeal joint (void arrow). Lack of bone erosion and of periosteal reaction suggests excluding bone involvement. b Longitudinal 17-5 MHz US images obtained at the level of the proximal interphalangeal joint reveal a conglomerate of calcifications
(arrows) filling the ventral joint recess (arrowheads) between the bone and the flexor tendons (ft). MPh, middle phalanx; PPh,
proximal phalanx. c Axial CT imaging correlation. d Surgical specimen of the same case shows the loose bodies
tate or dense lobular calcifications, which occur in
approximately two-thirds of cases. Treatment is surgical synovectomy; however, the recurrence rate is
over 25% (Sheldon et al. 2005).
5.3.5
Synovial Hemangioma
Synovial hemangioma is a rare intra-articular benign
tumor arising from the synovium that is difficult to
diagnose because of its nonspecific clinical presentation of nontraumatic recurrent swollen painful
knee (Narváez et al. 2001; Okahashi et al. 2004).
The knee of young adults and adolescents is usually
affected. Clinical symptoms are related to the mass
effect of the tumor, which leads to a decreased range
of motion and repetitive episodes of bleeding causing joint pain and swelling and possibly mimicking
other conditions, such as hemophilic arthropathy,
arthritis or medial shelf syndrome. Hemangiomas arising from the synovium have a similar US
appearance to other soft-tissue hemangiomas, but
the presence of hypoechoic tissue with fluid-filled
areas related to pooling of blood within vascular
spaces may generate confusion with more common
synovial conditions. Therefore, the examiner must
be aware of this condition to avoid making a wrong
diagnosis and wasting time for the patient. In the
cavernous type of synovial hemangioma, slow-flowing blood can occasionally be appreciated within the
anechoic spaces of the mass on gray-scale and color
179
180
M. P. Zamorani and M. Valle
F
F
a
b
&
c
d
e
f
Fig. 5.42a–f. Synovial hemangioma. a,b Transverse 12–5 MHz US images obtained over the suprapatellar region a without and
b with compression with the probe demonstrate a fluid-filled suprapatellar recess (arrows) containing slow-flowing swirling
echoes that change their echogenicity depending on the pressure exerted over them. F, femur. c Color Doppler imaging displays
venous flow filling the fluid-filled cavities contained in the recess. d Sagittal T2-weighted and e fat-suppressed postcontrast
T1-weighted MR imaging correlation show a markedly hyperintense lesion (arrow) containing linear low-signal structures
(arrowhead) representing fibrofatty septations and intratumor vascular channels. f Lateral radiograph reveals fullness of the
suprapatellar recess and scattered phleboliths (arrowheads), a feature of value for the diagnosis of synovial hemangioma
Doppler US (Fig. 5.42a–c). MR imaging of synovial
hemangioma is pathognomonic, with intermediate
T1-signal intensity and marked hyperintensity on
T2-weighted images and after gadolinium administration (Fig. 5.42d,e). Intratumor fat overgrowth,
low T2-signal vascular channels and phleboliths can
also be found (Fig. 5.42e,f). Circumscribed masses
can be resected on arthroscopy, whereas diffuse
lesions need open surgery (Sheldon et al. 2005).
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Radiology 187:459–463
185
Shoulder
Individual Anatomic Sites
Upper Limb
187
Shoulder
6
Shoulder
Stefano Bianchi and Carlo Martinoli
CONTENTS
6.1
Introduction 190
6.2
6.2.1
6.2.1.1
6.2.1.2
6.2.1.3
6.2.1.4
6.2.2
6.2.2.1
6.2.2.2
6.2.2.3
Clinical Anatomy 190
Osseous and Articular Anatomy 190
Glenohumeral Joint 190
Acromioclavicular Joint 191
Sternoclavicular Joint 193
Scapulothoracic Plane 193
Muscles and Tendons 193
Rotator Cuff 193
Biceps and Rotator Cuff Interval 196
Deltoid and Extrinsic Muscles of the
Shoulder 198
6.2.3 Bursae and Gliding Spaces 199
6.2.4 Neurovascular Structures 202
6.2.4.1 Suprascapular Nerve 202
6.2.4.2 Axillary Artery and Nerve 202
6.2.5 Thoracic Outlet Structures 202
6.2.5.1 Brachial Plexus Nerves and
Vertebral Anatomy 204
6.3
6.3.1
6.3.2
6.4
6.4.1
6.4.1.1
6.4.1.2
6.4.1.3
6.4.1.4
6.4.1.5
6.4.2
6.4.2.1
6.4.2.2
Essentials of Clinical History and
Physical Examination 205
Rotator Cuff Pathology 206
Thoracic Outlet and
Brachial Plexus Pathology 209
Normal Ultrasound Findings and
Scanning Technique 210
Biceps Tendon and Rotator Cuff 210
Long Head of the Biceps Tendon 210
Subscapularis Tendon 214
Supraspinatus Tendon 216
Infraspinatus and Teres Minor Tendons 223
Rotator Cuff Interval 226
Shoulder Beyond the Cuff 227
Glenohumeral Synovial Space 227
Subacromial Subdeltoid Bursa 229
S. Bianchi, MD
Privat-docent, Université de Genève, Consultant Radiologist,
Fondation et Clinique des Grangettes, 7, ch. des Grangettes,
1224 Genève, Switzerland
C. Martinoli, MD
Associate Professor of Radiology, Cattedra “R” di Radiologia
– DICMI – Università di Genova, Largo Rosanna Benzi 8, 16132
Genova, Italy
189
6.4.2.3
6.4.2.4
6.4.2.5
6.4.2.6
Acromioclavicular Joint and Os Acromiale 232
Glenoid Labrum 234
Nerves around the Shoulder 235
Brachial Plexus and
Other Nerves of the Neck 235
6.5
6.5.1
6.5.1.1
6.5.1.2
6.5.2
6.5.2.1
6.5.2.2
6.5.2.3
6.5.2.4
6.5.2.5
6.5.2.6
6.5.2.7
6.5.2.8
6.5.2.9
6.5.3
6.5.3.1
6.5.3.2
6.5.3.3
6.5.4
Shoulder Pathology 242
Pathophysiologic Overview 242
Impingement and Rotator Cuff Disease 242
Instability 245
Rotator Cuff Pathology 246
Cuff Tendinopathy 247
Partial-Thickness Tears 248
Full-Thickness Tears 251
Complete and Massive Tears 256
Intramuscular Cysts 259
Cuff Tear Arthropathy 262
Acromioclavicular Cysts 265
Postoperative Cuff 267
Calcifying Tendinitis 269
Biceps Tendon Pathology 275
Biceps Tendinopathy 275
Biceps Tendon Rupture 276
Biceps Tendon Instability 279
Shoulder Pathology Beyond the
Rotator Cuff 283
6.5.4.1 Pectoralis and Deltoid Lesions 284
6.5.4.2 Adhesive Capsulitis (Frozen Shoulder) 287
6.5.4.3 Glenohumeral Joint Instability 289
6.5.4.4 Humeral Head Fractures 292
6.5.4.5 Degenerative Arthropathies and
Loose Bodies 296
6.5.4.6 Inflammatory Arthropathies 300
6.5.4.7 Shoulder Arthroplasty 302
6.5.4.8 Septic Arthritis and Bursitis 303
6.5.4.9 Acromioclavicular Joint Trauma and
Instability 304
6.5.4.10 Sternoclavicular and
Costosternal Joint Pathology 307
6.5.4.11 Quadrilateral Space Syndrome 307
6.5.4.12 Suprascapular Nerve Syndrome 309
6.5.5 Thoracic Outlet and
Brachial Plexus Pathology 313
6.5.5.1 Brachial Plexus Trauma 313
6.5.5.2 Neoplastic Involvement of the
Brachial Plexus 315
6.5.5.3 Parsonage-Turner Syndrome 317
6.5.5.4 Thoracic Outlet Syndrome 318
6.5.6 Shoulder Masses 321
6.5.6.1 Elastofibroma Dorsi 322
References
324
190
S. Bianchi and C. Martinoli
6.1
Introduction
6.2
Clinical Anatomy
The shoulder is one of the most common applications of musculoskeletal US due to the high incidence of rotator cuff disorders related to increasing
aging and sporting activities. Many papers dealing with the US scanning technique of the rotator cuff tendons have already been published in
the radiological, rheumatologic and orthopaedic
literature and US is now widely recognized as an
accurate means to evaluate rotator cuff disease
(Ptasznik 2001; Bouffard et al. 2000; Brasseur
et al. 2000; Thain and Adler 1999; Bretzke et
al. 1985; Collins et al. 1987; Crass et al. 1985;
Hall 1986; Middleton et al. 1984; Middleton
et al. 1986b; Mack et al. 1988a; Middleton 1989;
Seibold et al. 1999; Teefey et al. 2000; Naredo
et al. 2002). With appropriate equipment and
skilled hands, this technique provides assessment
of rotator cuff pathology with high sensitivity and
specificity in the diagnosis of both partial and fullthickness tears with some specific advantages over
MR imaging, such as higher resolution capabilities
and the ability to examine tissues in both static
and dynamic states and with the patient in different positions.
In addition to the rotator cuff, interest is also
growing in the US evaluation of a variety of abnormalities of articular and para-articular structures located in and around the shoulder area
(Martinoli et al. 2003). These conditions can
mimic rotator cuff tears clinically and most commonly involve the glenohumeral and acromioclavicular joints and the soft-tissue structures around
the shoulder, including the joint recesses, the bone
and articular cartilage, the subacromial subdeltoid
bursa, the labrum, the muscles and the suprascapular and axillary nerves. In these cases, US is able to
redirect the diagnosis if a complete examination of
the shoulder area is performed instead of a simple
rotator cuff assessment. Furthermore, we include
in this chapter a specific focus on the US assessment of brachial plexus nerves and the thoracic
outlet syndrome as well as the US evaluation of
local tumors leading to painful shoulder or snapping scapula syndrome.
As for other sites in the body, a deep knowledge
of anatomy, of the proper scanning technique and
of the normal imaging findings is essential in order
to perform an accurate shoulder examination with
US.
6.2.1
Osseous and Articular Anatomy
The shoulder girdle is composed of the scapula, the
clavicle and the proximal humerus acting as a single
biomechanical unit. Three joints – the glenohumeral, acromioclavicular and sternoclavicular joints
– and two gliding planes – the subacromial and the
scapulothoracic – allow a greater range of motion
in the shoulder than is possible at any other joint in
the body, reaching approximately 180° in almost all
directions of movement. It is clear that such a wide
range of shoulder mobility depends on these joints
and gliding planes working together with synchronicity, in order to permit the arm and the hand to be
positioned as required in space around the body.
6.2.1.1
Glenohumeral Joint
The glenohumeral joint is a “ball-and-socket” joint
made up of the relatively small and flat glenoid fossa
and the large and round articular surface of the
humeral head (Fig. 6.1a,b). Owing to a discrepancy in
the size and curvature of the joint surfaces, the glenoid
cavity covers only a small portion (about one-fourth)
of the humeral head. This incongruity along with
the relative laxity of the joint capsule provides wide
mobility but makes the joint inherently unstable and,
therefore, prone to subluxation and dislocation. The
articular surfaces of the humeral head and the glenoid
fossa are covered by a layer of hyaline cartilage, which
is thicker in its center in the humerus and thinner at its
outer edges in the glenoid (Fig. 6.1b). In the humerus,
the articular cartilage reaches the anatomic neck, the
site of attachment of the joint capsule. Closely attached
at its base to the periphery of the glenoid, a concentric
rim of fibrocartilage, the labrum, widens and deepens
the shallow concavity of the bony glenoid, providing
the joint with inherent stability and restricting anterior
and posterior excursions of the humerus. Similar to
the meniscus of the knee, the glenoid labrum has a triangular shape and is in direct continuity with the hyaline cartilage of the glenoid cavity (Fig. 6.1b). A loose
fibrous capsule envelops the joint, extending from the
base of the coracoid through the supraglenoid region
cranially, onto the anatomic neck of the humerus laterally, and into the labrum posteriorly and inferiorly,
Shoulder
lar joint receives cranial-caudal shearing load due
to muscle action. Because the articular surfaces of
this joint are obliquely oriented, the applied tension
leads the clavicle to slide and displace cranially. This
tendency is resisted by the coracoclavicular ligaments, damage to which allows the typical superior
prominence of the clavicle end.
6.2.1.3
Sternoclavicular Joint
The sternoclavicular joint is the only articulation of
the shoulder girdle with the thorax. It is a shallow
saddle-shaped joint between the manubrium of the
sternum and the first rib medially and the medial
end of clavicle laterally. The articular surfaces of the
manubrium and the clavicle are, at least in part, incongruent, that of the clavicle being wider than that of the
manubrium. The sternoclavicular joint houses a fibrocartilaginous disk dividing the joint space into medial
and lateral cavities, each of which lined with its own
synovial membrane. The costoclavicular and interclavicular ligaments reinforce the joint and oppose to its
tendency to anteroposterior instability.
6.2.1.4
Scapulothoracic Plane
The scapulothoracic plane separates the body of the
scapula and the subscapularis muscle from the thoracic surface, consisting of the superficial aspect of
the serratus anterior muscle which overlies the ribs.
This gliding plane allows the scapula and the glenoid
cavity to tilt anteriorly and posteriorly around the
rib cage during shoulder movements. In addition,
the scapulothoracic articulation has an important
role in shoulder abduction.
6.2.2
Muscles and Tendons
From the anatomic point of view, the muscles of the
shoulder may be subdivided into two main groups:
intrinsic muscles (subscapularis, supraspinatus,
infraspinatus, teres minor, teres major and deltoid),
which originate and insert on the skeleton of the
upper limb, and extrinsic muscles, which join the
upper limb with either the spine (trapezius, latissimus dorsi, levator scapulae and rhomboid) or the
thoracic wall (serratus anterior, pectoralis minor
and pectoralis major). The clinical relevance is for
the most part related to the intrinsic muscles and
especially to the rotator cuff muscles and tendons.
6.2.2.1
Rotator Cuff
There are four rotator cuff muscles: the subscapularis, which is located on the anterior aspect of the
shoulder; the supraspinatus, which lies on its superior aspect; and the infraspinatus and teres minor,
which are situated on the posterior shoulder (Fig. 6.3).
They arise from the anterior and posterior aspects
of the scapula. The subscapularis muscle takes its
origin from the anterior aspect of the body of the
scapula. The muscle belly gives rise to a series of two
or three intramuscular tendons which direct laterally to join together to form the subscapularis tendon
(Fig. 6.4). This tendon inserts onto the lesser tuberosity in a broad band and acts as an adductor and
internal rotator of the arm. Its more cranial fibers
are intra-articular in location and some of its superficial fibers overlay the bicipital sulcus and reach the
greater tuberosity, merging with the coracohumeral
and transverse humeral ligament. The supraspinatus muscle originates from the supraspinous fossa
of the scapula and passes underneath the acromion
and above the glenohumeral joint before inserting on
the upper facet of the greater tuberosity (Fig. 6.5a).
It is separated from the acromion, coracoacromial
ligament and deltoid muscle by the subacromialsubdeltoid bursa. Anatomic studies indicate that the
supraspinatus consists of two distinct portions: ventral and dorsal (Fig. 6.5b) (Vahlensieck et al. 1994).
The ventral portion takes its origin from the anterior supraspinous fossa and inserts anteriorly onto
the greater tuberosity to act as an internal rotator
of the arm. This ventral portion may have an accessory site of insertion onto the lesser tuberosity. The
dorsal portion of the supraspinatus lies more posteriorly, with muscle fibers arising from the posterior
aspect of the supraspinous fossa and spine of the
scapula, assuming a strap-like configuration made
up of several small tendon slips that coalesce into a
broad attachment inserting more posteriorly onto the
greater tuberosity. This is the portion that acts primarily as a shoulder abductor. The individual layers of
the supraspinatus tendon have different mechanical
properties, leading to shearing between them, and
can tense and slacken depending on shoulder movements. On the posterior shoulder, the infraspinatus
muscle originates from the infraspinatus fossa and
193
194
S. Bianchi and C. Martinoli
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Fig. 6.3a–c. Projectional images of rotator cuff muscles and tendons as seen in an anterior (a), lateral (b) and posterior (c)
view of the shoulder. Note the relationship of the supraspinatus (SupraS), subscapularis (SubS), infraspinatus (InfraS), teres
minor (Tm) and long head of the biceps tendon (asterisk) with the main palpable bony landmarks of the shoulder, including
the acromion (Acr), the clavicle (Cl), the greater tuberosity (GT), the lesser tuberosity (LT) and the coracoid process (C). The
coracoacromial ligament is shown as a blue strip covering the biceps and the supraspinatus
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Fig. 6.4a,b. Subscapularis anatomy. a Gross cadaveric view through the anterior aspect of the shoulder after removal of the
deltoid muscle. The muscle belly of the subscapularis (SubS) has a broad origin from the anterior fossa of the scapula and
converges into a flat and wide tendon (asterisks) which inserts onto the lesser tuberosity (LT). More caudally, another broad
tendon, that of the pectoralis major (PectMj), parallels the course of the subscapularis inserting onto the lateral slip of the
intertubercular sulcus. b Gross cadaveric view of the same specimen shown in a after removal of the myotendinous junction
of the subscapularis displays part of the humeral head (H) covered by cartilage and the glenohumeral joint cavity (star). Note
the tight acromioclavicular joint (arrowheads) delimited between the acromion (Acr) and the clavicle end (Cl). Drawing at the
right side of the figure indicates the position of the subscapularis (in black) relative to the other cuff tendons and the biceps
(in grey) as seen on a lateral view through the shoulder
gives rise to a wide tendon that extends laterally to
insert onto the greater tuberosity, just posterior and
inferior to the supraspinatus tendon (Fig. 6.6). The
teres minor muscle, the smallest muscle of the rotator cuff, has a more oblique course than that of the
infraspinatus. This latter muscle arises from a narrow
strip on the lateral border of the scapula and inserts
just posterior and inferior to the infraspinatus into
the most caudal segment of the greater tuberosity
(Fig. 6.6). The posterior infraspinatus and teres minor
muscles act as external rotators of the arm.
Considered as a whole, the tendons of the rotator cuff muscles are broad and relatively flat, somewhat similar to belts, and converge toward the lesser
and greater tuberosity to create a hood – commonly
referred to as the “rotator cuff” – that covers the
humeral head anteriorly, superiorly and posteriorly (Fig. 6.7). The subscapularis tendon is sepa-
Shoulder
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Fig. 6.5a,b. Supraspinatus anatomy. a Gross cadaveric view through the cranial aspect of the shoulder after removal of the
trapezius and deltoid muscles. The origin of the supraspinatus muscle (SupraS) from the supraspinous fossa of the scapula is displayed. The supraspinatus muscle traverses the subacromial space passing underneath the acromioclavicular joint
(arrowheads) to converge, over the humeral head (HH), in a strong tendon which inserts into the cranial aspect of the greater
tuberosity. Observe the orientation of the acromion (Acr) and clavicle (Cl) compared with the long axis of the supraspinatus.
b Gross cadaveric view through the lateral aspect of the shoulder after removal of the trapezius, the deltoid and the structures
forming the acromioclavicular joint. The supraspinatus is shown in its long axis. The tendon consists of a smaller anterior portion (dashed arrows) and a larger posterior portion (large arrow). Both insert into the greater tuberosity (GT). Some fibers from
the anterior portion of the supraspinatus may even insert into the lesser tuberosity after crossing the interval and the biceps
tendon (asterisk). Note the acromion (Acr) and the coracoid (C) on each side of the supraspinatus. Drawing at the right side
of the figure indicates the position of the supraspinatus (in black) relative to the other cuff tendons and the biceps (in grey) as
seen on a lateral view through the shoulder
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Fig. 6.6a,b. Infraspinatus and teres minor anatomy. a,b Gross cadaveric view through the posterior aspect of the shoulder after
removal of the deltoid muscle illustrates the separate origin of the cranial infraspinatus (InfraS) and caudal teres minor (Tm)
muscles from the infraspinous fossa of the scapula. These muscles converge to insert onto the posterior aspect of the greater
tuberosity (GT) by means of two separate tendons (asterisk, infraspinatus; star, teres minor). Cranial to them, note the position
of the scapular spine (arrows). Drawing at the right side of the figure indicates the position of the infraspinatus and teres minor
(in black) relative to the other cuff tendons and the biceps (in grey) as seen on a lateral view through the shoulder
rated from the other tendons of the rotator cuff by
the ligamentous complex of the rotator interval and
the long head of biceps tendon, which is positioned
between it and the supraspinatus. The rotator cuff
tendons have a constant relationship in the different positions of the humerus and, as a result of
their combined activity, play an important role as
stabilizers of the humeral head in the glenoid fossa
during movements of the arm (for this reason, the
rotator cuff tendons have also been referred to as
“active ligaments”). The abduction of the arm when
the humerus is kept close to the side of the body, for
example, is mainly accomplished by contraction
of the deltoid muscle, but the force of this muscle
is also directed cranially, so that the humeral head
would displace upward. The combined action of
195
Shoulder
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Fig. 6.8a–c. Long head of the biceps tendon anatomy. a Gross cadaveric view through the glenohumeral joint cavity reveals the
glenoid cavity (GC) covered by hyaline cartilage and surrounded by a thick fibrocartilaginous labrum (arrows). The biceps
tendon (asterisk) arises from the top of the glenoid rim, in continuity with the superior glenoid labrum. b Arthroscopic view
of the glenohumeral joint displays the origin of the long head of the biceps tendon (curved arrow) from the superior aspect of
the glenoid (Gl). H, humeral head. c Gross cadaveric view through the proximal humerus demonstrates the curvilinear course
of the biceps tendon (asterisks) as it reflects over the anterosuperior aspect of the humeral head, between the supraspinatus
(SupraS) and subscapularis (SubS) tendons to reach the furrow between the greater and the lesser tuberosity, the intertubercular
groove. Drawing at the right side of the figure indicates the position of the long head of the biceps tendon (in black) relative to
the cuff tendons (in grey) as seen on a lateral view through the shoulder
3UPRA3
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Fig. 6.9a–c. Rotator cuff interval anatomy. Gross cadaveric views through the humeral head. a The long head of the biceps tendon (asterisks) is restrained between the supraspinatus (SupraS) and the subscapularis (SubS) tendons by a fibrous plate which
courses above it and the joint capsule as a roof (arrows), reflecting the coracohumeral ligament and some crisscrossing fibers
of the supraspinatus and subscapularis. b Fine anatomic dissection of the fibrous plate covering the biceps tendon (asterisks)
reveals fibers of the coracohumeral ligament (curved arrow) overlying the joint capsule (arrowhead). Note the intra-articular
location of the biceps tendon. c As the dissection progresses with more extensive removal of the joint capsule, the biceps tendon
(asterisks) becomes visible up to its origin from the top of the glenoid rim. On the medial side of the biceps, a well-defined fibrous
band reflects the superior glenohumeral ligament (arrows). Just cranially to the intertubercular groove, this ligament passes deep
to the biceps tendon and joins the medial part of the coracohumeral ligament (not shown) to form the reflection pulley
referred to as the “reflection pulley,” is more flexible
than the fibrous plate described above (Weishaupt
et al. 1999; Werner et al. 2000; Patton et al. 2001).
It assumes a crescentic shape surrounding the anteromedial aspect of the biceps tendon(Fig. 6.9c). More
distally, in the proximal bicipital groove, the biceps
tendon lies in close contact with the subscapularis
and is stabilized by fibrous bands arising from it.
The superficial component of these fibers forms the
transverse humeral ligament that, in distal continuity with the coracohumeral ligament, bridges the
tuberosities transforming the biceps sulcus into
an osteofibrous tunnel. The transverse humeral
ligament is thin and weak and its role in stabilizing the biceps just distal to its exit from the rotator interval is not considered important unless the
coracohumeral ligament is torn (Patton et al. 2001;
Bennett 2001).
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S. Bianchi and C. Martinoli
The other belly of the biceps, the short head, takes
its origin from the tip of the coracoid process of the
scapula, in a more medial location than the long
head, in close contact with the tendon of the coracobrachialis. The long and short bellies of the biceps
continue down in two separate muscle bellies which
join together just distal to the middle third of the arm
to form a long fusiform muscle (see also Chapter 7).
In contrast to the long head of the biceps, the tendon
of the short head has a straight course and is not
invested by a synovial sheath. In the rare cases when
it is involved in shoulder pathology, this is usually
injured as a result of to trauma (i.e., anteroinferior
dislocation of the shoulder) or inflammatory states.
6.2.2.3
Deltoid and Extrinsic Muscles of the Shoulder
In addition to the rotator cuff muscles and the biceps,
the intrinsic muscles of the shoulder include the
teres major and the deltoid. The teres major muscle
arises from a raised oval area at the dorsal aspect
of the inferior angle and the adjacent lateral border
of the scapula and inserts into the medial lip of the
intertubercular groove of the humeral shaft. This
muscle acts as an adductor and medial rotator of the
humerus and plays a role in stabilizing the proximal humerus during abduction. Together with the
tendon of latissimus dorsi, the teres major forms
part of the posterior wall of the axilla. The deltoid
is a thick and powerful muscle supplied by the axillary nerve which forms something of a roof over the
rotator cuff tendons and the glenohumeral joint. Its
name derives from the fact that its shape is similar to
an inverted Greek letter delta (∆). This muscle has a
wide origin from the lateral third of the clavicle, the
acromion and the spine of the scapula, and inserts
on the anterolateral surface of the humerus at the
middle third of the arm. The action of the deltoid
muscle is multifaceted. In fact, it can be a flexor
and medial rotator of the humerus with its anterior
fibers (in that assisting the coracobrachialis, the subscapularis and the pectoralis major), an abductor
of the humerus with its middle fibers (assisting the
supraspinatus) and an extensor and lateral rotator of
the humerus with its posterior fibers (assisting the
infraspinatus and teres muscles). The primary function of the deltoid muscle, however, is to abduct the
humerus. When the supraspinatus is torn, the abduction of the arm becomes the only result of a deltoid
contraction, although the upward pull of the deltoid
leads to superior subluxation of the humeral head.
The extrinsic shoulder muscles which join the
upper limb with the spine are the trapezius, the latissimus dorsi, the levator scapulae and the rhomboids. Among them, the trapezius is the most relevant during examination of the shoulder with US.
This muscle is broad, flat and overlies the posterior
neck and the superior half of the posterior trunk
with a triangular shape (hypotenuse facing the
spine). Its name derives from the fact that it becomes
a trapezius when the muscles of the two sides are
considered as a single muscle. The trapezius has
a wide origin from the external occipital protuberance, the ligamentum nuchae and the spinous
processes of C7 to T12 vertebrae and attaches to the
lateral third of the clavicle, the acromion and the
spine of the scapula. The trapezius receives supply
from the accessory nerve and some cervical nerves
(III–VII), and has its primary function in the elevation and rotation of the scapula.The extrinsic muscles which joint the shoulder with the thoracic wall
are the pectoralis major, the pectoralis minor and
the serratus anterior. The pectoralis major muscle
is a strong fan-shaped muscle covering most of the
upper part of the chest wall and forming, with its
lateral part, the anterior wall of the axilla. This
muscle is separated from the more cranial deltoid
by a groove, the deltopectoral triangle, which is traversed by the cephalic vein (Fig. 6.10a). The pectoralis major has three heads arising respectively from
the anterior aspect of the medial half of the clavicle
(clavicular head), from the manubrium and body of
the sternum and the costal cartilages from II to VI
ribs (sternocostal head), and from the aponeurosis
of the external oblique muscle (abdominal head).
The muscle fibers converge laterally into a broad
trilaminar tendon which crosses the myotendinous
junction of the long head of the biceps and inserts
on the lateral lip of the intertubercular groove of
the humerus (Wolfe et al. 1992). The tendon layers
fuse and twist 90° just before the tendon insertion
at the lateral lip of the bicipital groove, where the
posterior lamina inserts cranially and the anterior
lamina comprises the most caudal part of the enthesis (Fig. 6.10a,b). Distal to the humeral tuberosities,
the pectoralis tendon participates in retaining the
long head of biceps tendon close against the anterior aspect of the humeral shaft. The main action
of the pectoralis major is to adduct and internally
rotate the humerus. Deep to the pectoralis major,
the pectoralis minor is a smaller triangular muscle
which takes its origin from the III, IV and V ribs
and inserts onto the medial border of the coracoid
process. It stabilizes the scapula against the tho-
Shoulder
Del
1
2
3
1
3
2
1
2
Tendon
3
Muscle
a
b
Fig. 6.10a,b. Pectoralis major anatomy. a Frontal photograph of the thorax taken while the patient kept the arm abducted and
b schematic drawing correlation of an anterior view through the shoulder show the distinct orientation of the clavicular head
(1), the sternocostal head (2) and the abdominal head (3) of the pectoralis major muscle. They converge to form a broad tendon
inserting into the lateral lip of the intertubercular groove. The separate contributions to this tendon twist on each other so that
at the level of the axillary fold the tendon fibers of the clavicular head pass superficial to those arising from the sternal head
and insert caudally, whereas the fibers from the abdominal head have the most cranial attachment onto the humeral shaft. Note
the cephalic vein (arrowheads) as it traverses the space between the deltoid (Del) and the clavicular head of the pectoralis (1)
– the deltopectoral triangle – where it deepens to reach the subclavian vein
racic wall and is a useful landmark for the axillary vessels and nerves as it lies just superficial to
them.
Figure 6.11 illustrates the anatomic relationship
among intrinsic and extrinsic muscles of the shoulder and the bones by means of one-to-one correlation between cadaveric specimens and CT images.
6.2.3
Bursae and Gliding Spaces
Knowledge of the anatomy of synovial recesses and
para-articular bursae is an essential prerequisite to
avoid misdiagnoses and pitfalls in the interpretation
of pathologic findings. Three main synovial spaces
are found around the shoulder area: the glenohumeral joint cavity, the subacromial-subdeltoid
bursa and the acromioclavicular cavity. In normal
conditions, these spaces are separated from one
other because the rotator cuff is interposed between
the glenohumeral joint and the subacromial-subdeltoid bursa and the acromioclavicular capsule is
found between the acromioclavicular joint and the
subacromial-subdeltoid bursa. In some pathologic
states, such as a defect in the rotator cuff or in the
inferior capsule of the acromioclavicular joint, these
spaces can communicate.
The subacromial space, which is located between
the coracoacromial arch and the humeral head, contains the rotator cuff tendons, the long head of the
biceps tendon, the subacromial-subdeltoid bursa
and a variable amount of connective tissue and fat
(Fig. 6.12). The subacromial-subdeltoid bursa is a
large synovium-lined structure located inferior to
the acromion and the coracoacromial ligament that
overlies the superior aspect of the supraspinatus
tendon (Fig. 6.13). It also extends medially to the
coracoid (subcoracoid bursa) and anteriorly to cover
the bicipital groove, whereas its lateral and posterior
boundaries are more variable and reach approximately 3 cm below the greater tuberosity (Bureau
et al. 1996). From the functional point-of-view, the
main role of the subacromial-subdeltoid bursa is to
minimize the attrition of the cuff against the coracoacromial arch and the deltoid during movements
of the arm. To facilitate gliding, the bursa is surrounded by a thin cleavage plane of peribursal fat.
The subcoracoid bursa may be separated from the
subacromial-subdeltoid bursa to form an individual
cavity. In these cases, the bursa lies just inferiorly
and medially to the coracoid and may simulate a
cystic mass when distended by fluid if the examiner
is not aware of its existence. In addition, care should
be taken not to mistake it for the adjacent subscapularis recess of the glenohumeral joint.
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PMj
Da
Da
PMj
C
V
C
Cl
Cl
HH
V
G
LS
G
SubS
LS
Dm
HH
Dm
SubS
Tra
InfraS
Tra
Dp
Dp
InfraS
Da
Da
Cl
Da
PMj
Da
Acr
PMj
Pm CB
SB
Pm
HH
SB
CB
HH
Dm
Dm
Cl
Acr
Dm
Tm
G
SupraS
SubS
Tra
InfraS
Tm
G
SubS
InfraS
Dp
Dp
Tra
Da
PMj
Da
Da
Pm CB
HH
HH
SupraS
HH
Tm
G
Dp
SB
CB
HH
C
Dm
C
Pm
Dm
Da
PMj
SB
Dm
Dp
PMj
Da
Da
*
HH
G
InfraS
Da
Pm
*
*
Dp
Dm
Da
PMj
CB SB
Pm
SB
CB
HH
HH
Dm
Dp
InfraS
SupraS
C
Dm
SubS
InfraS
C
Tm
G
SubS
HH
Dm
SubS
G
Dm
G
G
Tm
Tm
SubS
InfraS
Dp
Dp
InfraS
InfraS
Dp
Fig. 6.11. Sectional anatomy of the shoulder. Series of cadaveric sections (left) and corresponding CT images (right) displayed
in sequence from cranial to caudal. Acr, acromion; Arrowheads, cleavage plane between infraspinatus and deltoid; asterisks,
rotator cuff; C, coracoid process; CB, coracobrachialis; Cl, Clavicle; curved arrow, spinoglenoid notch; Da, deltoid, anterior part;
Dm, deltoid, middle part; Dp, deltoid, posterior part; G, glenoid; LS, levator scapulae; HH, humeral head; InfraS, infraspinatus;
open arrow, bicipital groove; Pm, pectoralis minor; PMj, pectoralis major; SB, short head of the biceps; stars, fibrocartilaginous
glenoid labrum; SubS, subscapularis; SupraS, supraspinatus; Tm, teres minor; Tra, trapezius; V, axillary vessels; white arrow,
anterior bundle of fibers of the supraspinatus tendon
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S. Bianchi and C. Martinoli
In addition to the subacromial gliding plane, the
scapulothoracic plane facilitates movement of the
scapula relative to the chest wall and rotation of the
scapula during abduction and adduction of the arm.
6.2.4
Neurovascular Structures
The rotator cuff muscles receive nerve supply from
the suprascapular nerve (supraspinatus and infraspinatus), the subscapular nerve (subscapularis)
and the axillary nerve (teres minor). The examiner
should be aware of the anatomic course of the suprascapular and axillary nerves because these nerves are
vulnerable to stretching injuries and trauma and
may be involved by extrinsic compression (i.e., paralabral ganglia) leading to well-categorized entrapment syndromes: the suprascapular nerve syndrome
(see Sect. 6.5.4.12) and the quadrilateral space syndrome (see Sect. 6.5.4.11). The musculocutaneous
nerve will be described in Chapter 7.
6.2.4.1
Suprascapular Nerve
The suprascapular nerve originates from the
upper trunk of the brachial plexus (C5–C6 level)
and descends through the suprascapular foramen
formed by the supraspinous notch of the scapula
and the superior transverse scapular ligament to
reach the supraspinous fossa (Fig. 6.14). Then,
the nerve continues inferiorly to the supraspinatus muscle passing through the tunnel formed by
the inferior transverse scapular ligament and the
spinoglenoid notch to distribute in the infraspinous fossa (Fig. 6.14). In the supraspinous fossa,
the suprascapular nerve gives off motor branches to
the supraspinatus muscle, whereas the innervation
to the infraspinatus muscle is provided by distal
branches arising in the infraspinous fossa. Along
its entire course, the suprascapular nerve is accompanied by the suprascapular vessels.
6.2.4.2
Axillary Artery and Nerve
The axillary artery continues the subclavian artery
beyond the outer border of the first rib. It traverses
deep to the pectoralis minor muscle and is accompanied by the cords and distal branches of the bra-
chial plexus, and the axillary vein. The axillary artery
can be palpable in the inferior part of the axilla, in
proximity to the inferior glenohumeral joint capsule.
Distal to the lateral border of the pectoralis minor, it
sends three branches: subscapular, and anterior and
posterior circumflex humeral arteries. The circumflex arteries have a horizontal course and anastomose to form a circle around the anterior and posterior aspect of the surgical neck of the humerus. The
anterior circumflex humeral artery is smaller than
the posterior and runs deep to the coracobrachialis
and the biceps and in front of the surgical neck of
humerus. It gives off an ascending branch, the arcuate
artery, which accompanies the long head of the biceps
tendon in the intertubercular groove. The posterior
circumflex humeral artery is larger and crosses the
posterior wall of the axilla through the quadrilateral
space in association with the axillary nerve. It is a
landmark for the US detection of the nerve.
The axillary nerve arises from the posterior cord
of the brachial plexus (C5–C6 level) near the coracoid
process and proceeds along the inferolateral border
of the subscapularis muscle to curve inferior to the
glenohumeral joint capsule and pass into the posterior aspect of the arm. The nerve courses in association with the posterior circumflex artery through the
quadrilateral space – a squared passageway bounded
by the long head of the triceps muscle medially, the
surgical neck of the humerus laterally, the teres minor
muscle cranially and the teres major muscle caudally
(Fig. 6.15) (Loomer and Graham 1989). It has two
terminal branches: anterior and posterior. The anterior branch supplies the anterior deltoid muscle and
overlying skin; the posterior branch innervates the
teres minor and the posterior deltoid muscle and distributes to the skin overlying the distal deltoid and
the proximal triceps muscle.
6.2.5
Thoracic Outlet Structures
The thoracic outlet region includes the brachial
plexus nerves and the subclavian artery and vein.
These neurovascular structures traverse restricted
spaces in which they can be compressed, the most
important of which are the interscalene triangle, the
costoclavicular space and the retropectoralis minor
space (Fig. 6.16a) (Demondion et al. 2000). Both
subclavian artery and brachial plexus nerves pass
through the interscalene triangle, a space bordered
by the anterior scalene muscle anteriorly, the middle
scalene muscle posteriorly and the first rib inferiorly.
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S. Bianchi and C. Martinoli
C5
a
b
C6
*
C7
*
T1
short physical examination and a review of previous imaging studies.
6.3.1
Rotator Cuff Pathology
First, the examiner should check whether previous
shoulder accidents, including acute trauma, chronic
microtrauma, sport-related injuries and episodes of
shoulder instability, have occurred. Special attention should be given to the location, type, severity and circumstances of the referred pain. Patients
with rotator cuff pathology typically complain of
night pain and inability to sleep on the affected side.
Generally speaking, the location and irradiation of
shoulder pain is not related to involvement of a
specific tendon. Most patients are fairly accurate in
localizing pain. Often, patients with supraspinatus
tendon tear complain of pain irradiated along the
lateral aspect of the upper and middle third of the
arm, in proximity to the insertion of the deltoid
muscle. Pain distal to the elbow level in association
with paresthesias is usually related to cervical or
brachial plexus disorders rather than an isolated
rotator cuff pathology. Next, the patient should be
asked what kind of movement produces discomfort, or the examiner should attempt to produce
pain with different maneuvers. In anterosuperior
impingement syndrome, pain is reported during
activities or maneuvers that require active abduction and forward elevation of the arm. Exacerbation
Fig. 6.17a,b. Vertebral anatomy: neural
foramina. a Schematic drawing of the
cervical spine illustrates the anatomic
correspondence between transverse
processes and nerve roots. Each root (in
yellow) leaves the intervertebral foramen
sliding on the transverse process of its
corresponding vertebral level. Because
there are eight cervical nerves and only
seven cervical vertebrae, the C8 root lies
at the level of the T1 vertebra. The position f the vertebral artery (in red) relative to the bony tubercles b Photograph
of the cervical spine shows the typical
appearance of transverse processes,
which exhibit prominent anterior (star)
and posterior (asterisks) tubercles. Note
the absence of the anterior tubercle at C7
level, whereas the lateral aspect of T1 is
flat without any bony prominence
of pain can also be noted during maximal elevation
of the arm and internal rotation in posterosuperior
impingement and during maximal internal rotation
and adduction of the arm in anteromedial impingement.
A basic physical examination of the affected
shoulder for rotator cuff assessment is part of the
routine US study (Moosikasuwan et al. 2005).
The examination begins with observation on how
the patient is undressing, because the act of slipping the shirt off is an indicator of the full range of
movements that the patient is able to perform and is
typically limited in rotator cuff disease. Then, the
overall range of shoulder motion can be assessed
by asking the patient to place the dorsal aspect of
the hand behind the back as cranially as possible,
between the scapulae (internal rotation and extension), and behind the neck (external rotation and
abduction). With the patient seated, the affected
shoulder is inspected and simultaneously palpated
by the examiner. Swelling and tenderness around the
shoulder, especially when located over the anterior
aspect of the joint, more likely reflects an effusion
in the subacromial subdeltoid bursa rather than an
intra-articular effusion. In chronic cuff tears, palpable crepitus over the cranial aspect of the shoulder
can be produced by rotation of the shoulder with the
arm in 90° of elevation. A localized soft-tissue lump
over the cranial aspect of the acromioclavicular joint
is often related to a cyst arising from the acromioclavicular joint which develops following massive
rotator cuff tear (Geyser Sign). Care should be taken
Shoulder
to correlate it with the tear because patients usually
take medical advice for the lump and not for the
underlying disorder (Fig. 6.18a). Ecchymosis over
the anterior aspect of the shoulder and arm is typically correlated with an acute tear of the long head
of biceps tendon but it may also be appreciated in
cases of traumatic enlargement of a previous tear of
the supraspinatus or subscapularis tendons. Except
for the subscapularis, atrophy of rotator cuff muscles can be appreciated by inspection and palpation.
Although the occurrence of a bilateral cuff rupture
should be always kept in mind, comparative examination of the two shoulders for asymmetry may help
the examiner to evaluate muscle atrophy. On the
lateral shoulder, deltoid atrophy may reveal wasting
from axillary neuropathy or from previous surgery
with deltoid detachment for rotator cuff repair. On
the posterior shoulder, wasting of the infraspinatus
and teres minor muscles may derive from chronic
rotator cuff tears, disuse, glenohumeral arthritis and
suprascapular nerve palsy (Fig. 6.18b). In patients
with biceps tendon tear, the retracted muscle can
be palpated as a soft-tissue lump over the anterior
aspect of the middle third of the arm, possibly mimicking a hypertrophied muscle, the so-called Popeye
sign (Fig. 6.18c). Detection of the retracted biceps
can be difficult in obese patients. Rotator cuff tendons may be palpated systematically for focal tenderness starting anteriorly with the subscapularis
and the biceps and then moving posteriorly to evaluate the insertions of the supraspinatus and infraspinatus into the superior and posterior facets of the
greater tuberosity. Finally, the acromioclavicular
a
b
joint is assessed by applying a firm pressure over it
with the thumb. If this pressure generates pain, the
ache should be compared with that recalled by the
patient to ensure matching of symptoms. A painful
acromioclavicular joint may indicate an arthritic or
traumatized joint. Acromioclavicular joint separation is noted by the painful prominence of the distal
end of the clavicle associated with excessive mobility of the joint.
The overall range of shoulder motion is frequently affected in patients with rotator cuff disorders. In these cases, examination of passive motion
may be helpful to differentiate a real impingement
syndrome with rotator cuff pathology from adhesive capsulitis (frozen shoulder). Whereas in rotator
cuff disease without secondary adhesive capsulitis
the range of motion is restricted during active but
not passive motion, shoulder motion in adhesive
capsulitis is always lost. In this disorder, the motion
is for the most part restricted in external rotation
tested in both 0° and 90° of abduction, although all
directions are usually involved to some extent. Specific clinical tests to evaluate the strength of individual rotator cuff tendons have been described in
the orthopaedic literature (Hawkins and Hobeika
1983). Supraspinatus function can be evaluated by
testing the patient’s ability to resist a downward force
applied to the humerus with the elbow extended and
the arm in a position of internal rotation and 45° of
forward flexion (Fig. 6.19a). If positive, the test generates pain, weakness or both symptoms. Then, two
impingement maneuvers, which may be performed
with the patient standing or supine, may help the
c
Fig. 6.18a–c. Physical findings around the shoulder. a Geyser sign. Photograph of the right shoulder shows a soft-tissue lump
(arrow) over the cranial aspect of the acromioclavicular joint reflecting a cyst. This sign is pathognomonic of a complete tear
of the supraspinatus tendon. b Wasting of the supraspinatus and infraspinatus resulting from suprascapular nerve palsy. Compared with the opposite side, note the loss in bulk of muscles contained in the supraspinous (arrowhead) and infraspinous
(arrow) fossa of the right shoulder. c Popeye sign. Photograph shows a prominent lump (arrow) over the anterior aspect of
the middle arm related to a ruptured long head of the biceps tendon. This sign results from the distal retraction of the muscle
belly because of the tendon tear
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S. Bianchi and C. Martinoli
a
b
Fig. 6.19a,b. Clinical tests for assessing the strength of rotator cuff muscles. a Supraspinatus strength is tested with the patient’s
arm in a position of 60° of forward elevation with the shoulder internally rotated and the elbow extended. A downward force
(arrow) applied by the examiner is resisted by the patient. b A lift-off test is performed to evaluate subscapularis strength. The
patient is asked to actively lift (arrow) the hand off of the lumbar region
examiner to assess shoulder pain related to rotator
cuff disease or biceps tendinitis. The first, which
is referred to as Neer’s test, is obtained with maximal passive glenohumeral forward flexion with the
shoulder in neutral rotation to obtain impingement
of the supraspinatus and the biceps against the
anterolateral margin of the acromion (Neer 1983).
The second, Hawkins’ test, is performed with 90°
forward flexion, slight horizontal adduction and
internal rotation to compress the insertion of the
supraspinatus and the subacromial bursa under the
coracoacromial ligament (Hawkins and Hobeika
1983). The internal rotation of the shoulder reflects
the action of the subscapularis tendon and can be
assessed by means of the “lift-off test” (Gerber and
Krushell 1991). To avoid the contribution of other
muscles (i.e., pectoralis major, teres major) to internal rotation, this test measures the strength of the
subscapularis in isolation by positioning the forearm behind the patient’s back. The patient is then
asked to lift her or his hand off of the lumbar region,
an action that requires the active contraction of the
subscapularis (Fig. 6.19b). Inability to perform this
maneuver indicates subscapularis tear. The combined action of the infraspinatus and teres minor
cannot be differentiated during external shoulder
rotation. The ability of these muscles considered as
a whole can be estimated using the “horn-blower
sign,” in which the patient’s arm is passively brought
into 90° of abduction and full external rotation. The
examiner holds the elbow while the patient is asked
to maintain maximal external rotation. Any loss of
active external rotation represents weakness of the
posterior rotator cuff, whereas failure to maintain
full external rotation of the abducted arm suggests a
large posterior rotator cuff defect. Posterior deltoid
contraction could give a false negative Hornblower‘s sign. Performing the test bilaterally is useful to
avoid this potential pitfall (Hawkins and Hobeika
1983). Although strength tests are useful to support
the clinical suspicion of rotator cuff disease, they
have been found to have varying sensitivity and
specificity in the diagnosis. Sonologists must at least
be familiar with them because the orthopaedist can
cite these maneuvers in the request for a US examination. In patients who have undergone previous
surgery for rotator cuff tears, the examiner should
spend some additional time reviewing the surgical
report before starting the US examination, because
surgical procedures can alter the local anatomy. One
should also keep in mind that the surgical intervention may have consisted of acromioplasty and bursectomy without any suture of the torn tendons. In
these cases, discontinuity of the rotator cuff must
not be misinterpreted as a retear.
Although conventional radiography is somewhat limited in evaluation of the rotator cuff and
its findings become pathognomonic only in patients
with chronic tear, previous imaging studies should
be reviewed before starting the US examination.
Advising the patient or the referring physician the
day before the examination will usually ensure these
studies available. Standard radiographs are the most
common imaging studies performed before US examination. Pathologic changes associated with rotator
cuff disorders include intratendinous or bursal cal-
Shoulder
cifications, acromial spurs, erosions and sclerosis of
the tuberosities, a reduced subacromial space with
superior subluxation of the humeral head and a lateral downsloping or low-flying acromion. Inferior
humeral osteophytes, osteoarthritic changes and
undersurface osteophytes of the acromioclavicular
joint, and bony changes related to previous surgical
procedures can be appreciated as well. In anterior
shoulder dislocation, a compression fracture on the
posterolateral aspect of the humeral head – commonly referred to as the Hill-Sachs fracture – is seen
as the result of impaction of the displaced humeral
head against the anterior aspect of the glenoid rim.
Similarly, in the setting of posterior shoulder dislocation, a compression fracture on the anteromedial
aspect of the humeral head, the so-called reversed
Hill-Sachs or McLaughlin lesion, can be encountered due to the impaction of the humerus against
the posterior glenoid rim. Both abnormalities can
be detected on plain films and should redirect the
US examination toward an instability problem. The
examiner should be aware that the availability of
standard radiographs is time-saving and essential
for the adequate interpretation of troublesome US
images related to disorders that can be more obvious on plain films.
6.3.2
Thoracic Outlet and Brachial Plexus Pathology
Thoracic outlet pathology is conventionally divided
into two main types – vascular and neurogenic
– although vascular and nervous entrapment signs
and symptoms, such as pain, numbness, tingling,
weakness and other disturbances in the upper
limb, often coexist as a single clinical picture. In
general, brachial plexus nerves are more often
involved than subclavian vessels. Brachial plexus
syndromes often resemble more distal entrapment
neuropathies and are often mistaken for a lower
level (i.e., carpal tunnel, cubital tunnel) compression. To distinguish them from distal entrapment
of individual nerves, one should consider that sensory and motor system abnormalities encountered
in brachial plexus pathology are, in general, not
clearly attributable to a single nerve. Patients with
upper plexus involvement (C5–C7 level) complain of
pain in the region of the trapezius and shoulder, with
symptoms radiating along the lateral aspect of the
extremity down to the territory of innervation of the
median nerve. Motor symptoms include weakness of
shoulder abduction (involvement of the deltoid and
supraspinatus) and external rotation (involvement
of the infraspinatus and teres minor). In overt cases,
patients exhibit an extended and internally rotated
arm, a pronated forearm and a flexed wrist. On the
other hand, patients with lower plexus involvement
(C8–T1 level) feel pain in the supraclavicular region,
in the back of the neck and in the axilla down to
the area of the hand innervated by the ulnar nerve,
with sensory disturbances in the fourth and fifth
fingers. In longstanding disease, muscle weakness
may involve the ulnar-innervated muscles of the
hand and forearm (flexor carpi ulnaris) resulting in
a claw-hand deformity. Trauma to the neck, shoulder girdle and even the upper limb is often associated with the onset of a thoracic outlet syndrome
related to brachial plexus involvement. Brachial
neuritis (Parsonage Turner syndrome) may also be
suspected when the onset of shoulder pain and disability follows a viral illness or unrelated previous
surgical procedure. Apart from nerves, if the subclavian vein is selectively compressed, symptoms
are mostly related to increased venous pressure in
the upper extremity. Entrapment of the subclavian
artery is rare and usually presents with arterial
insufficiency and a cold extremity.
When examining a patient with suspected thoracic outlet syndrome, objective findings are, in
many cases, few. The physical examination should
include general evaluation of the musculoskeletal
and vascular systems of the upper extremity looking for temperature changes and areas of muscle
atrophy. The supraclavicular and infraclavicular
area should be palpated for tenderness and a radiating Tinel sign. Several provocative tests may be
performed both before and during the US examination, including the Adson maneuver (Adson and
Coffey 1927), the hyperabduction test or Wright
maneuver (Wright 1945), the Eden maneuver, or
military position (Eden 1939), and the Roos maneuver (Roos 1976). In particular, the Adson maneuver
is performed by holding the patient’s arm down and
checking the radial pulse while the patient inspires
deeply and keeps the head extended and turned
toward the involved extremity. The Wright maneuver is obtained with the patient seated or standing
and the shoulder hyperabducted and rotated externally. If the test is positive, the patient complains
of paresthesias in the extremity and any change in
arterial pulse. The Roos test is performed by means
of a 3-minute abduction with exercise (clenching
fists). While performing these tests, the examiner
must be aware that positive findings may also occur
in normal subjects.
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6.4
Normal Ultrasound Findings and Scanning
Technique
When examining the shoulder with US, appropriate
positioning of the patient is essential to allow the
examiner access to the patient’s shoulder and the
US keyboard simultaneously. Positioning should
be comfortable for the patient and the examiner,
and allow examination of the shoulder in as short
a time as possible. Different patient positions have
been reported for the US examination of the shoulder, likely reflecting the preference and habit of the
examiner. Many sonologists examine the shoulder
using an anterior approach, standing in front of the
patient while he or she is seated on the examination
bed. Generally speaking, the anterior approach is
easier to learn for the beginner and offers greater
opportunity to correlate US images with probe
positioning based on skin landmarks. At least in
our opinion, this is particularly true while evaluating anterior structures, such as the biceps tendon
and the rotator interval. Other sonologists prefer to
perform the examination by a dorsal approach with
the patient seated on the bed or on a revolving stool.
This approach allows the examiner to perform a
brief physical examination and prevents excessive
backward curvature of the spine, thus improving
the US assessment of the supraspinatus (Lyons and
Tomlinson 1992). In addition, the dorsal approach
makes guiding the patient to assume different arm
positioning easier and increases stability during
scanning (Allen and Wilson 2001). Depending on
the examiner’s and patient’s height, an appropriate
adjustment of the bed level allows a more comfortable examination, while a revolving stool makes
the approach to the different aspects of the joint
easier. An additional technique in which the patient
is examined supine with the arm hanging down the
side of the bed has been described for a better evaluation of the internal structure of the supraspinatus
(Turrin et al. 1997; Turrin and Capello 1997).
The US examination is well tolerated by patients
and even preferred to MR imaging (Middleton
et al. 2004A). The main reasons for this preference
probably include a shorter examination time, the
lack of discomfort related to positioning within the
magnet, and a free environment with contact with
the medical personnel and absence of the sense of
isolation and anxiety which is typically produced
during MR imaging examinations (Middleton et
al. 2004a).
Because most indications for shoulder US are concerned with the rotator cuff, most of this section will
focus on the examination of these tendons. Before
discussing the normal US anatomy and examination
technique of the cuff, some important points should
be taken into account.
a. Rotator cuff US needs a rigorous standardized
technique to obtain systematic and comprehensive assessment of the individual tendons within
a short examination time.
b. While examining the rotator cuff with US, it is
essential to perform the assessment of each of the
four tendon–muscle units and the biceps tendon
by means of scanning planes oriented according
to their long-axis and short-axis. Although this
approach might seem boring and time-consuming, it is the only way that ensures subtle pathologic findings are not missed. This is true even for
skilled examiners.
c. Each tendon should be evaluated systematically
from its myotendinous junction to the bony insertion and in the proper position during maximal
tendon stretch so that the bony structures that
limit US access, such as the acromion and the
coracoid process, are moved away from it.
6.4.1
Biceps Tendon and Rotator Cuff
Apart from the type of approach used, we perform
a standard US examination of rotator cuff tendons
starting with the long head of the biceps tendon as the
initial key reference. The examination of the biceps is
then followed by scanning the anterior (subscapularis), superior (supraspinatus) and posterior (infraspinatus and teres minor) aspects of the rotator cuff. To
avoid confusion with the spatial planes of the body,
we prefer to use the terms “long-axis” and “shortaxis” rather than “longitudinal” and “transverse” to
indicate the orientation of the scanning plane according to the axis of the examined structure.
6.4.1.1
Long Head of the Biceps Tendon
In most patients, the biceps tendon is assessed with
the arm in neutral position. In most instances, a
slight internal rotation of the arm can be helpful
for a more accurate assessment. The first landmark
to identify is osseous: the intertubercular sulcus,
which is also referred to as the “bicipital groove.”
Shoulder
It lies between the lesser and the greater tuberosities and has a well-defined concave appearance
(Fig. 6.20a,b). Once the groove is found, one should
check its appearance, looking at its depth and presence of focal cortical erosions (Fig. 6.20c–e). The
two tuberosities do not have the same appearance,
the lesser having a more pointed and the greater
a more rounded look. Care should be taken to
examine the content of the bicipital groove. This
cavity holds the long head of the biceps tendon
invested by its proper synovial sheath, along with
the ascending branch of the anterior circumflex
artery, located on the lateral side of the tendon, and
fatty tissue (Fig. 6.21). Visualization of the arcuate artery depends on its size and flow volume.
In younger patients, it is almost invariably found.
Awareness of its presence can avoid misdiagnosis of
tendon sheath hyperemia. The transverse humeral
ligament appears as a very thin hyperechoic band
overlying the sulcus (Fig. 6.20b).
GT
LT
GT
a
*
LT
b
a
GT
b
GT
c
Short-axis scans are the most useful planes for
evaluating the biceps tendon. Because this tendon
courses from cranial to caudal and from superficial to deep, a careful scanning technique is needed
to distinguish it from both the adjacent fat (which
is not affected by anisotropy and always appears
hyperechoic) and the sheath fluid (Middleton et
al. 1985). In fact, if the transducer is not maintained
parallel to the tendon, this may appear artifactually
hypoechoic mimicking fluid (Fig. 6.22a–c). Often,
the transducer must be rocked slightly to ensure
the best visualization of the fibrillar echotexture.
In particular, a slight tilting of the probe (short-axis
scans) or a slight pressure exerted with its caudal
end on the skin (long-axis scans) may be helpful
for this purpose (Fig. 6.22c,d,f). Once the tendon
has reached maximum reflectivity, the orientation
of the transducer should maintained constant while
shifting the probe up and down. Cranially, at the
intra-articular level, the biceps tendon assumes a
GT
LT
LT
LT
d
e
Fig. 6.20a–e. Bicipital groove. a Anterior view of the proximal humerus from a caudal perspective reveals the bicipital groove
(arrowhead) lying between the greater (GT) and the lesser (LT) tuberosities. b Corresponding 12–5 MHz transverse US image demonstrates the normal biceps tendon (asterisk) as a rounded echogenic structure contained within the bicipital groove
(arrowheads). Over the tendon, a straight hypoechoic layer (curved arrow) related to the transverse humeral ligament bridges
the greater (GT) and the lesser (LT) tuberosities transforming the bicipital sulcus into an osteofibrous tunnel. The US appearance of the intertubercular sulcus closely resembles the outline of bone visible in a. In this case, it has normal size and shape.
c Congenital shallow intertubercular sulcus. The groove is wider and has flat walls. The depth of the groove can be measured
on short-axis planes. A line (a) is first drawn tangential to the tuberosities; then, the distance (b) between this line and the
deepest point of the groove is calculated: a distance ⱕ3 mm indicates a shallow sulcus and can be considered a predisposing
cause for biceps tendon instability. d,e Bicipital groove osteophytes leading to an abnormally narrow sulcus and even to a true
bicipital tunnel. Bony proliferation in this area may be associated with attrition of the tendon causing progressive narrowing
of the biceps (arrow) and, perhaps, its rupture
211
Shoulder
of the biceps should be always evaluated because a
tear or calcification may occur at this level. In the
evaluation of the long head of the biceps tendon, the
importance of long-axis scans is limited to confirm
the tendon integrity in doubtful cases based on visualization of its fibrillar echotexture. The pectoralis
tendon is a broad flattened tendon which crosses
anterior to the biceps to insert into the lateral lip
of the intertubercular groove, receiving contributions from the three heads of the muscle: clavicular
(superficial layer), sternal (intermediate layer) and
abdominal (deep layer). When the arm is internally
rotated, this tendon assumes an arcuate course over
the biceps, whereas it becomes straight in external
to the humeral tuberosities, the long head of the
biceps tendon lies in front of the proximal humeral
metaphysis. It is important to examine this level
because even small effusions tend to fill the most
dependent portion of the tendon sheath (Fig. 6.23).
In this area, a small amount of intrasheath fluid, not
sufficient to encircle the tendon, is a normal finding
and should not to be indicated in the report. More
caudally, the myotendinous junction of the biceps
tendon can be appreciated as a gradual decrease
in the size of the tendon and a parallel increase in
the size of the muscle. It lies deep to the tendon of
the pectoralis major and lateral to the short head
of the biceps muscle (Fig. 6.24a). The distal portion
SupraS
Capsule
InfraS
GT
*
SubS
**
bt *
H
Synovium
Hs
a
Hs
b
bt
*
c
*
*
bt
*
d
Fig. 6.23a–d. Biceps tendon sheath. a Schematic drawing of a coronal view through the anterior shoulder demonstrates the
relationships of the long head of the biceps tendon (bt) with the rotator cuff tendons, including the subscapularis (SubS), the
supraspinatus (SupraS) and the infraspinatus (InfraS). In its intra-articular portion, the biceps tendon is overlaid by the capsule
of the glenohumeral joint. More distally, the biceps enters the intertubercular sulcus, coursing in between the greater (GT) and
the lesser (LT) tuberosities. At this level, it is invested by a sheath of synovial membrane which represents an anterior extension
of the glenohumeral joint. b Short-axis 12–5 MHz US image over the biceps tendon (bt) obtained approximately 2 cm below
the bicipital groove with c transverse T2-weighted MR imaging correlation reveals the sheath of the biceps tendon distended
by fluid (asterisks). Note the mesotendon (arrowhead) connecting the visceral and parietal layers of the synovial envelope. Hs,
humeral shaft. d Long-axis 12 –5 MHz US image over the extra-articular long head of the biceps tendon (bt) demonstrates a
small amount of sheath effusion (asterisks). The overall longitudinal extension of the biceps tendon sheath is shown
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S. Bianchi and C. Martinoli
Hs
b
Hs
SubS
b
PMj
b
Hs
b
a
b
c
Fig. 6.24a–c. Pectoralis major tendon. a Schematic drawing of a coronal view through the anterior shoulder and the upper arm
shows the humeral insertion of the pectoralis major (PMj) and the relationships of its tendon with the myotendinous junction
of the long head of the biceps brachii muscle (b) and the more cranial subscapularis (SubS). Owing to its broad insertion, the
pectoralis tendon is best examined by means of transverse planes shifting the probe up and down over it (arrows). The insert
on the upper right side of the image illustrates the relationship of the pectoralis major tendon (arrowheads) with the underlying
myotendinous junction of the biceps brachii (b). Hs, humeral shaft. b,c Transverse 12–5 MHz US images obtained on the long
axis of the pectoralis major tendon (arrowheads) while the arm is kept b in external and c internal rotation. In external rotation, the tendon has a straight course pushing the myotendinous junction of the biceps toward depth. In internal rotation, the
tendon is relaxed and tends to assume an arcuate course over the biceps. Note the more anterior position of the biceps relative
to the pectoralis insertion on the humeral shaft (Hs)
rotation (Fig. 6.24b,c). It is best evaluated with the
arm abducted and externally rotated to stress the
myotendinous region (Rehman and Robinson
2005). US is able to distinguish the three heads of
the pectoralis major muscle but not the individual
components of the tendon because the three tendon
layers blend with no significant intervening connective tissue (Rehman and Robinson 2005).
6.4.1.2
Subscapularis Tendon
After the biceps has been examined, the patient is
asked to rotate the arm externally in order to evaluate the subscapularis tendon on the anterior aspect
of the shoulder. This maneuver stretches the subscapularis and helps to move its tendon from underneath the coracoid process into a more superficial
position for an adequate examination (Fig. 6.25).
Dynamic scanning during passive internal and
external rotation with the arm adducted may also be
helpful to assess the integrity of the subscapularis.
While the arm is in external rotation, the examiner
must remember to neutralize the tendency for the
patient to lift and abduct the elbow from the lateral
chest wall. This can be easily avoided by keeping
the hand in supination while rotating the arm externally. Conditions limiting external rotation, such
as shoulder casting, may lead to a poor delineation
of the anterior structures. Any of these constraints
should be indicated in the report.
When examined on its short axis, the multipennate
structure of the normal subscapularis tendon creates
a series of hypoechoic clefts among the fascicles that
should not be confused with tendon tears (Fig. 6.26).
In fact, these cleft are related to muscle fibers interposed with tendon fascicles. On short-axis scans,
the lesser tuberosity has a flat appearance ending in
a smooth downsloping contour located just caudal
to the tendon insertion (Fig. 6.26). Such a bony landmark would be helpful when assessing partial tears
217
Shoulder
Deltoid
Deltoid
SubS
SubS
Co
HH
HH
a
b
Fig. 6.28a,b. Short head of the biceps tendon, coracobrachialis and pectoralis minor. a,b Transverse 12–5 MHz US images
obtained a at the level of the coracoid process of the scapula and b approximately 2 cm caudal to it. In a, the relationship of
the coracoid (Co) with the humeral head (HH), the subscapularis tendon (SubS) and the deltoid muscle are illustrated. The
coracoid is easily identified with US owing to its medial position relative to the humeral head and the curvilinear hyperechoic
appearance of its bony surface. In b, three individual structures are seen arising from the coracoid. From lateral to medial,
they are: the hyperechoic tendon of the short head of the biceps (curved arrow), the hypoechoic myotendinous junction of the
coracobrachialis (straight arrow) and that of the pectoralis minor (arrowheads)
Del
Acr
GT
a
Del
Acr
GT
b
Fig. 6.29a,b. Appropriate positioning for visualization of the supraspinatus tendon. Long-axis 12–5 MHz US images obtained
over the supraspinatus tendon (arrowheads) with the arm a in neutral position and b flexed at the elbow while keeping the hand
placed over the posterior iliac crest and the elbow directed posteriorly (modified Crass or Middleton position). The supraspinatus tendon appears as a thick echogenic structure (arrowheads) emerging from underneath the acromion (Acr) to insert into the
greater tuberosity (GT). In b, the acromion is moved away from the tendon and can be depicted in its full extent, even including
visualization of its myotendinous junction. The gray vertical bars indicate the respective tendon extension as it appears in the
US images. In this position, it is important to realize that the long axis of the tendon is oriented approximately 45° between the
sagittal and coronal planes. Del, deltoid. The inserts at the upper left side of the figure indicate arm positioning
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S. Bianchi and C. Martinoli
bt
a
b
Fig. 6.38a,b. Coracoacromial ligament. a Schematic drawing of a lateral view through the rotator cuff demonstrates the proper
transducer positioning to examine the coracohumeral ligament. It has to be shifted proximally when oriented in the short axis
over the anterior supraspinatus tendon (SupraS). Acr, acromion; C, coracoid; SubS, subscapularis tendon. b Corresponding 12–5
MHz US image demonstrates the coracohumeral ligament (arrowheads) as a slightly convex fibrillar band which overlies the
myotendinous junction of the supraspinatus and the biceps tendon (bt). Note that the supraspinatus exhibits two discrete origins
for the anterior cylindrical bundle (large arrow) and the posterior flat tendon component (thin arrows)
forearm in a supination on the ipsilateral thigh or
with the patient’s hand on the opposite shoulder. We
believe the first approach works better as it avoids
repositioning of the tendon too anteriorly, which
may make it difficult to separate its fibers from the
supraspinatus. Using such a posterior approach, the
spine of the scapula may be a useful landmark to distinguish these tendons (Fig. 6.39). First, one should
palpate the scapular spine and place the transducer
over it, in a more medial position relative to the
greater tuberosity (Fig. 6.39a): shifting the transducer up on the sagittal plane, the supraspinous
fossa and the supraspinatus muscle can be found
deep to the trapezius muscle (Fig. 6.39b). After that,
the infraspinatus and teres minor muscle can be
depicted as individual structures deep to the deltoid muscle by shifting the transducer down to the
scapular spine (Fig. 6.39c). Each of these muscles is
characterized by a central aponeurosis and should
be evaluated and compared for size and echogenicity
(Fig. 6.40a). The teres minor muscle is smaller than
the infraspinatus and has a rounded cross-section
while the infraspinatus is more oval in appearance.
In some cases, these muscles are fused together and
exhibit a common elongated central aponeurosis
(Fig. 6.40b). Systematic scanning over these muscles
may help to rule out echotextural changes related to
tendon tears and nerve pathology. In fact, certain
shoulder diseases, such as suprascapular neuropa-
thy, can be recognized on the basis of muscle atrophy
detected in these scans. After scanning the muscles,
the transducer is swept toward the greater tuberosity
on sagittal planes and the two tendons can be appreciated as individual hyperechoic structures arising
from the respective muscles, the larger and more
cranial being the infraspinatus, and the smaller and
caudal, the teres minor (Fig. 6.41). Often, the profile
of the posterior aspect of the greater tuberosity can
demonstrate two separated facets at the insertion
of these tendons (Fig. 6.41). On long-axis scans, the
infraspinatus tendon appears as a thick beak-shaped
structure coursing deep to the deltoid and superficial to the posterior aspect of the humeral head, the
posterior labrum and the bony glenoid (Fig. 6.42a).
The teres minor tendon, the smallest tendon of the
cuff, has a more oblique course than that of the infraspinatus and arises eccentrically with respect to the
muscle (Fig. 6.42b). Therefore, the probe should be
oriented obliquely to image it in its long axis. Each
tendon must be examined separately. Care should
be taken to evaluate the infraspinatus tendon up to
its insertion. In fact, at least when the arm is kept
in internal rotation, the tendon may project over the
lateral rather than the posterior aspect of the shoulder. Dynamic scanning during passive internal and
external rotation with the arm adducted may help
the examiner to assess the insertion level and the
integrity of both tendons.
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S. Bianchi and C. Martinoli
1
2
2
1
a
b
Fig. 6.41a,b. Normal infraspinatus and teres minor tendons. a Sagittal 12–5 MHz US image over the short axis of the infraspinatus
and teres minor tendons. These tendons can be seen arising from, respectively, the larger infraspinatus muscle (open arrows)
and the smaller teres minor muscle (white arrow). Note two separate facets (1, 2) in the posterior aspect of the greater tuberosity (dashed line) for the insertion of these tendons. b Photograph over the posterior aspect of the humeral head illustrates the
shape of the greater tuberosity (dashed line) as well as the two facets (1, 2) for tendon insertion depicted with US. The insert
at the upper left side of the figure indicates transducer positioning
a
Deltoid
Deltoid
b
HH
*
a
HH
Gl
b
Fig. 6.42a,b. Normal infraspinatus and teres minor tendons. a,b Transverse 12–5 MHz US images over the long axis of a the infraspinatus and b the teres minor tendons. a The infraspinatus tendon arises within the muscle from a thick central aponeurosis
(arrowhead) and appears as a thick beak-shaped structure (arrows) coursing deep to the deltoid muscle and superficial to the
posterior aspect of the humeral head (HH), the posterior labrum (asterisk) and the bony glenoid (Gl). b Immediately caudal
to it, the teres minor tendon (arrows) appears as a smaller fibrillar structure arising eccentrically relative to the muscle belly
(arrowhead). The inserts at the upper left side of the figure indicate the respective transducer positioning. Note the slightly
oblique orientation of the probe needed to image the teres minor tendon along its major axis
6.4.1.5
Rotator Cuff Interval
Before entering the bicipital groove, the biceps tendon
passes across the “rotator cuff interval”, a free space
delimited by the subscapularis and supraspinatus
tendons. In this space, the biceps tendon is retained
in its proper location by the coracohumeral ligament, which courses above it as a roof, and by the
superior glenohumeral ligament (Fig. 6.43a, 6.44a).
At US, the coracohumeral ligament can be appreciated as a thick homogeneous echogenic band of
tissue, tightened between the subscapularis and
the supraspinatus and located just over the biceps
(Fig. 6.43b). Often, a thin hypoechoic layer is seen
arising from the deep edge of the supraspinatus
tendon and intervening between the ligament and
the biceps tendon, a finding that may represent the
joint capsule (Fig. 6.43b). The coracohumeral ligament is best depicted on short-axis scans while the
arm is kept in posterior flexion, because this position causes maximal opening of the rotator cuff
interval, stretches the biceps against the humeral
cartilage and tightens the ligament. Careful scan-
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S. Bianchi and C. Martinoli
CHL
SupraS
*
SGHL
GT
SupraS
LT
*
SubS
SubS
a
b
SupraS
GT
**
LT
SubS
GT
*
LT
c
SubS
d
Fig. 6.44a–d. Rotator cuff interval: intermediate and distal levels. a Schematic drawing with b corresponding transverse 12–5 MHz
US image of the intermediate level of the rotator cuff interval. The medial cord of the coracohumeral ligament (CHL) and the
superior glenohumeral ligament (SGHL) form an anterior sling (arrowheads) around the biceps tendon (asterisk), the so-called
reflection pulley. In the US image, note that the biceps is elevated at this site relative to the bone and assumes an oblique orientation due to the pulley which surrounds it with a crescentic shape. The deep fibers of the pulley that infiltrates the undersurface
of the biceps tendon are part of the superior glenohumeral ligament. SubS, subscapularis; SupraS, supraspinatus. c Schematic
drawing with d corresponding transverse 12–5 MHz US image of the distal level of the rotator cuff interval. In the proximity
of the bicipital groove, the biceps tendon (asterisk) lies in contact with the lesser tuberosity (LT) and the subscapularis tendon
(SubS) and is stabilized by fibrous bands arising from it. Arrowheads indicate the insertion of the supraspinatus tendon into
the greater tuberosity (GT)
of movement of the arm. The large axillary recess
arises, for instance, from a deep folding of the capsule that permits a complete elevation of the arm
without stretching the inferior capsule. The same is
true for the anterior and posterior recesses, which
allow maximal external and internal rotation of the
arm. In normal states, the small amount of synovial
fluid contained in the joint space cannot be recognized with US. On the other hand, US has high
sensitivity for appreciating even a minimal amount
of pathologic fluid inside the main synovial recesses
(i.e., the dependent axillary pouch, the posterior and
anterior recesses and the sheath of the long head of
the biceps tendon).
Although a caudal approach through the axilla has
been described to evaluate the axillary pouch, posterior transverse scans are usually preferred for better
accessibility. Once the teres minor tendon is localized,
the transducer is shifted more caudally to investigate
the space intervening between the humeral metaphysis and the inferior neck of the scapula, where the
axillary pouch lies. If distended by considerable effusion, this pouch is visible as a fluid-filled area.
The posterior recess is best examined on transverse scans by placing the transducer over the infraspinatus tendon (Fig. 6.45). An effusion filling the
posterior recess appears as a hypoanechoic crescent
surrounding the tip of the posterior labrum. In larger
effusions, the infraspinatus tendon can be seen displaced posteriorly by the fluid contained in the recess.
In doubtful cases, the examiner can induce changes
in the shape of the recess by passively moving the
patient’s arm externally and internally, which results
in reduced/increased tension of the posterior capsule
and the overlying infraspinatus. Due to the lack of
intervening vessels and easy accessibility, procedures
of needle aspiration or injection in the posterior recess
can be safely performed under US guidance while the
patient is seated or prone (Fessell et al. 2000; Zwar
et al. 2004). This recess can be selected for a safe USguided needle placement for shoulder arthrography
(Cicak et al. 1992; Valls and Melloni 1997).
Shoulder
InfraS
HH
*
Gl
a
*
b
Fig. 6.45a,b. Posterior recess of the glenohumeral joint. a Transverse 12–5 MHz US image over the posterior shoulder with
b gradient-echo T2*-weighted MR imaging correlation demonstrates a hypoechoic effusion (asterisk) distending the posterior
recess. This recess is located between the humeral head (HH) and the posterior aspect of the bony glenoid (Gl), deep to the
infraspinatus (InfraS) tendon and muscle
US evaluation of the anterior recess is more complex due to its deep location, and often requires a
small curved-array transducer, lower frequencies
and a careful scanning technique. When fluid is
present in the anterior recess, it can be appreciated
on transverse scans as a hypoechoic halo surrounding the anterior labrum. Similarly, the subscapularis recess (also known as the subscapularis bursa) is
difficult to evaluate reliably with US because of its
small size and problems of access related to its location deep to the coracoid tip. This is a small saddlebag-shaped recess located between the anterior neck
of the scapula and the subscapularis tendon which
may extend above the tendon to overlie its anterior
aspect. Using transverse or sagittal scans, the main
landmark to find is the coracoid: an effusion in the
subscapularis recess can be demonstrated as a small
hypoanechoic area located just caudally and posteriorly to the bone and adherent to the subscapularis
tendon (Fig. 6.46). The subscapularis recess should
not be confused with the larger subcoracoid bursa
that extends more caudally and does not communicate with the glenohumeral joint as it is an extension
of the subacromial subdeltoid bursa (Figs. 6.46b,
6.47) (Grainger et al. 2000). The subcoracoid bursa
lies deep to the conjoined tendon of the short head
of the biceps and the coracobrachialis, in a more
medial location relative to the subscapularis tendon
and the coracoid, and may contain abundant effusion in cases of anterior rotator cuff tears (Fig. 6.47c).
It is best examined while keeping the patient’s arm
adducted by scanning just inferiorly and medially to
the coracoid. The distinction between the subscapularis recess and the subcoracoid bursa is relevant
because the causes of a subscapularis recess effusion
may be different from the causes of a subcoracoid
bursa effusion (which is most often associated with
rotator cuff tears, including tears of the rotator cuff
interval) (Grainger et al. 2000).
Finally, the synovial sheath of the long head of the
biceps tendon is formed by an extrusion of the articular synovial membrane. As the sheath is merely an
extension of the joint cavity, intra-articular effusion
can lead to fluid in the sheath (see Fig. 6.23). Fluid
secondary to an isolated biceps tendinitis is rare.
6.4.2.2
Subacromial Subdeltoid Bursa
The subacromial subdeltoid bursa appears as a
2 mm thick complex comprised of an inner layer
of hypoechoic fluid between two layers of hyperechoic peribursal fat (see Fig. 6.31) (van Holsbeeck
and Strouse 1993). In normal states, the synovial
membrane of the bursa cannot be depicted with US.
Hypoechoic thickening of the bursal walls can be
observed in a variety of shoulder disorders, among
which anterosuperior impingement is the most
important (Fig. 6.48a). In these instances, the bursa
assumes a pseudosolid appearance and may be difficult to delineate from the underlying supraspinatus tendon, somewhat mimicking a degenerative
tendinopathy. A notch sign in the upper profile of
the bursa at the point where it passes deep to the
coracoacromial ligament may help this differentiation (Fig. 6.48b,c). Because intrabursal fluid can
migrate depending on gravity and arm positioning,
229
230
S. Bianchi and C. Martinoli
Co
Co
*
CjT
SubS
*
SubS
a
c
Acr
Co
*
b
a
*
Gl
SubS
HH
b
CjT
*
d
Fig. 6.46a-d. Subscapularis recess of the glenohumeral joint. a Sagittal oblique T1-weighted MR image over the glenoid reveals
the extension of the superior subscapularis recess (asterisk) in a patient with joint effusion. The subscapular recess is a small
saddlebag-shaped recess lying anterior to the glenohumeral joint capsule, between the anterior neck of the scapula and the
subscapularis (SubS) which extends above this muscle to overlie its anterior aspect. Note the anterior glenohumeral joint cavity (straight arrows) with the middle glenohumeral ligament (arrowhead) and the posterior synovial recess (curved arrow). b
Schematic drawing of an oblique sagittal view through the glenoid (Gl) illustrates the relationships of the superior (asterisk)
and inferior (star) glenohumeral recesses with the superior (in yellow), middle (in purple) and inferior (in green) glenohumeral
ligaments. Observe that the superior subscapularis recess extends below the coracoid (Co) and above the subscapularis (a) up
to reach the anterior aspect of the muscle. This recess should not be confused with the adjacent subcoracoid bursa (arrowhead)
which intervenes between the subscapularis and the coracobrachialis and short head of the biceps tendon (b) and has a greater
caudal extension (see Fig. 6.47). Note the axillary (arrows) and posterior (curved arrow) recesses of the glenohumeral joint. Acr,
acromion. Unlike the superior subscapularis recess, the inferior recess (star) is smaller and lies deep to the subscapularis muscle.
c Sagittal 12–5 MHz US image over the coracoid process (Co) demonstrates the superior subscapularis recess (asterisk), which is
partially masked by the intervening bone and located between the conjoined tendon (CjT) of the short head of the biceps and
the coracobrachialis and the tip of the subscapularis (SubS). d Transverse 12–5 MHz US image obtained just below the coracoid
illustrates the relationships of the superior subscapularis recess (asterisks) with the conjoined tendon of the coracobrachialis
and the short head of the biceps (CjT) and the subscapularis (SubS). HH, humeral head
the various bursal portions should be systematically
assessed. Care should also be taken not to apply
excessive pressure with the probe over the bursa,
so as not to overlook small effusions. When the
patient is standing or seated, fluid tends to accumulate in the most dependent portions of the bursa
and, more commonly, along the lateral edge of the
greater tuberosity, producing a typical “teardrop”
sign (Fig. 6.49a) (van Holsbeeck and Strouse
1993). When effusion is contemporarily present
in the glenohumeral joint and the bursa, anterior
transverse planes are the best suited to demonstrate
fluid in both cavities. Using these planes, the intraarticular fluid can be appreciated as a hypoechoic
halo surrounding the long head of the biceps tendon,
while the bursal fluid appears as a crescent-shaped
collection located just deep to the anterior deltoid
muscle (Fig. 6.49b). The two effusions are separated
by a thin hyperechoic structure which represents
the bordering walls of the biceps tendon sheath and
the bursa. More abundant collections tend to fill the
bursal portion located posterior to the infraspinatus
tendon. In these cases, detection of the infraspinatus
may help to distinguish superficial bursal effusions
231
Shoulder
sBT
SubS
HH
Co
*
HH
a
*
SubS
CBr
CjT
*
*
SubS
b
c
Fig. 6.47a–c. Subcoracoid bursitis. Transverse 12–5 MHz US images obtained inferiorly and medially to the coracoid in three
patients with increasing distension of the subcoracoid bursa (asterisks). Similar to the subscapularis recess, the subcoracoid
bursa extends deep to the conjoined tendon (CjT) of the short head of the biceps (sBT) and the coracobrachialis (CBr) and medial to the subscapularis tendon (SubS) to reduce friction among these structures. When distended by large effusion, this bursa
extends more medially relative to the coracoid. A natural communication (arrowheads) between it and the larger subacromial
subdeltoid bursa may exist in some people, thus helping the examiner to distinguish subcoracoid bursitis from joint fluid in
the subscapularis recess. HH, humeral head
SupraS
*
2
a
1
GT
2
SupraS
3
1
b
c
Fig. 6.48a–c. Subacromial subdeltoid bursitis. a Short-axis and b long-axis 12–5 MHz US images over the supraspinatus tendon
(SupraS) demonstrate hypoechoic thickening of the bursal walls (arrowheads) and a small amount of fluid (asterisk) within
the bursal lumen. In a, the effusion tends to accumulate medially, in the dependent portion of the bursa. In b, the upper profile
of the bursa shows a deep notch (arrow) at the level of the myotendinous junction of the supraspinatus (SupraS) reflecting the
position of the coracoacromial ligament. c Schematic drawing of a coronal view through the shoulder illustrates the extension
of the subacromial subdeltoid bursa (arrowheads). This bursa is composed of the subacromial (1) and the subdeltoid (2) bursae,
which are in continuity and may extend laterally and inferiorly (3) even 3 cm below the greater tuberosity (GT). Similar to that
seen in b, note the notch in the bursal profile produced by the coracoacromial ligament (arrow)
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S. Bianchi and C. Martinoli
*
GT
*
SupraS
bt
*
*
InfraS
HH
HH
Hs
a
*
b
c
Fig. 6.49a–c. Dependent recesses of the subacromial subdeltoid bursa. a Coronal 12–5 MHz US image obtained at the proximal
humeral diaphysis, just distal to the supraspinatus tendon (SupraS) and the greater tuberosity (GT), reveals the lateral pouch
(asterisk) of the bursa distended by some fluid, the so-called teardrop sign. b Transverse 12–5 MHz US image over the anterior
shoulder shows effusion distending the bursal lumen (asterisks) both medially and laterally to the biceps tendon (bt). A small
amount of fluid (star) is also visible in the biceps tendon sheath. Note that the two spaces are separated by a hyperechoic cleavage
plane (arrowhead): they may communicate when a full-thickness tear of the rotator cuff occurs. Hs, humeral shaft. c Transverse
12–5 MHz US image over the posterior shoulder demonstrates the infraspinatus tendon (InfraS) which separates the superficial
posterior dependent portion of the bursa (asterisks) from the deep posterior synovial recess (star) of the glenohumeral joint.
HH, humeral head
from deep joint effusions (Fig. 6.49c). Demonstration of an effusion in both synovial spaces is, for
the most, an indicator of full-thickness tear of the
rotator cuff. Dynamic scanning performed with the
probe placed over one cavity – either the bursa or a
joint recess – while compressing the other with the
hand can reveal communication between the two
compartments as a result of rotator cuff tear.
6.4.2.3
Acromioclavicular Joint and Os Acromiale
To examine the acromioclavicular joint, the transducer is placed over the top of the shoulder in a
coronal plane. The width of the joint is measured
and compared with that of the contralateral side.
The evaluation of the acromioclavicular joint has
to be included as part of the routine study of the
shoulder, because its lesions can mimic rotator
cuff disease. In fact, this joint is intimately related
to the supraspinatus tendon, which runs directly
underneath the joint. In spite of a similar echogenicity, the superior acromioclavicular ligament can
be distinguished from the underlying joint cavity
using high-frequency probes and dynamic scanning (Fig. 6.50a,b). This ligament forms an external inextensible band joining the mobile ends of
the clavicle and the acromion, an appearance quite
different from the content of the acromioclavicular joint which is limp and can change shape and
width with shoulder movements. In young healthy
subjects, the internal fibrocartilaginous disk can
seldom be appreciated as a slightly hyperechoic
structure, an appearance somewhat similar to the
knee menisci or the glenoid labrum (Fig. 6.50c,d).
The coracoclavicular ligaments are difficult to be
detected with US due to the acoustic shadowing of
the overlying clavicle.
An os acromiale can occasionally be recognized
as an incidental finding while scanning the acromioclavicular joint with US (Fig. 6.51). This accessory
bone derives from the nonfused epiphysis of the anterior part of the acromion, has an overall frequency
of approximately 8% of general population and is
bilateral in one third of cases (Sammarco 2000).
The os acromiale is triangular in shape and has a
variable size (mean 22 mm). It can articulate with
the acromion and the clavicle with a distinct articulation, a fibrocartilaginous union or a nearly complete union (Sammarco 2000). The deltoid muscle
inserts on its anterolateral edge. The os acromiale is
a potential source of anterosuperior impingement,
either as a fragment mobilized by deltoid pulls or
from osteophyte lipping. US is a sensitive means to
identify or confirm this anomalous bone (Boehm et
al. 2003). The diagnosis is based on detection of a
well-defined cortical discontinuity on the superior
aspect of the acromion, often mimicking a double
acromioclavicular joint (Figs. 6.51, 6.52). At US, an
os acromiale may exhibit flat bony margins (type I),
marginal osteophytes (type II) or inverted bony
margins (type III) (Boehm et al. 2003). A confident
identification of the os acrominale from the adjacent
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S. Bianchi and C. Martinoli
Os
Cl
Acr
Os
a
c
b
Os
d
f
Cl
g
Acr
Acr
Os
*
e
Os
Cl
Os
Cl
*
Acr
h
Fig. 6.52a–h. Os acromiale. a,b Schematic drawings of a transverse view through the acromioclavicular joint showing adequate
transducer positioning for US depiction of an os acromiale with c,d corresponding 12–5 MHz US images. Two individual articulations are demonstrated instead of one, the pseudo-articulation of the accessory ossicle (Os) with the acromion (Acr) being
located in a more posterior site than expected for a true acromioclavicular joint. Cl, distal end of the clavicle. e,f Radiographic
appearance of an os acromiale imaged by means of e acromioclavicular and f Bernageau views. g,h Oblique coronal T2-weighted
MR images g over the pseudo-articulation of the os acromiale with the clavicle and h the acromion in a patient with rotator
cuff tear and abundant fluid collection (asterisk) in the subacromial subdeltoid bursa
acromioclavicular joint can easily be accomplished
by shifting and rotating the probe over the acromion
in order to identify two articulations instead of one.
In case of an associated rotator cuff tear, the treatment is varied. In patients with impingement symptoms, a small mobile os acromiale can be resected,
a large stable os acromiale treated by acromioplasty
and a large unstable os acromiale by fusion to the
acromion. The postoperative outcome is good.
6.4.2.4
Glenoid Labrum
The fibrocartilaginous labrum can be demonstrated
at US as a triangular homogeneously hyperechoic
structure capping the bony rim of the glenoid
(Schydlowsky et al. 1998a). The different portions
of the labrum lie at various depths, the inferior being
the most superficial and the anterior the deepest.
Consequently, an adequate US scanning technique
should first include a dynamic adjustment of the focal
zone, based on the characteristics of each individual
quadrant to be examined. The anterior labrum is
best scanned with curved-array transducers and
low frequencies (down to 5 MHz) using an anterior
transverse approach (Fig. 6.53a). The patient’s arm
is maintained adducted or abducted at 90° with the
elbow flexed or with an axillary transverse approach
placing the arm in the same position as before
(Hammar et al. 2001). While evaluating the anteroinferior quadrant of the glenoid, difficulties may
arise in patients who are obese or unable to put their
arm in the proper position because of pain or apprehension. Contrary to the anterior labrum, the posterior labrum is more superficial in position and can
be easily imaged at US using transverse planes while
placing the patient‘s hand on the opposite shoulder
(Fig. 6.53b). It appears as a triangular structure with
the base directed medially and the apex pointing
laterally. Changes in the shape of the labrum can be
observed in different rotations of the arm. A more
pointed appearance is noted when traction is applied
on it by the capsule (during internal rotation for the
posterior labrum). The superior labrum is very difficult to visualize due to problems of access related to
the acoustic shadowing of the acromion. A tentative
approach can be made in slender subjects by placing
the probe just behind the head of the clavicle while
abducting the arm to better differentiate the static
glenoid from the moving humeral head (Fig. 6.53c).
Even with appropriate technique, high-end equipment and skilled hands, US is unable to demonstrate
superior labrum abnormalities, such as anterior to
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S. Bianchi and C. Martinoli
Acr
SupraS
*
*
HH
Gl
a
InfraS
Gl
Gl
b
c
Fig. 6.54a,b. Supraspinous and spinoglenoid notches. a Oblique coronal 12–5 MHz US image obtained medial to the acromion
(Acr) reveals the supraspinous notch as a shallow groove located in the cranial aspect of the scapula just medial to the bony
glenoid (Gl) and the superior labrum (asterisk). A couple of tiny hypoechoic dots (arrow) are appreciated in the supraspinous
notch, deep to the supraspinatus muscle (SupraS), reflecting the suprascapular artery and the suprascapular nerve. b Transverse
10–5 MHz US image obtained over the posterior shoulder demonstrates the spinoglenoid notch (arrows) as a fat-filled concavity
of the scapula located at the base of the glenoid (Gl) and deep to the infraspinatus muscle (InfraS). Note the posterior labrum (asterisk) and the humeral head (HH). c Transverse 12–5 MHz color Doppler US image helps to distinguish the suprascapular artery
(arrowhead) from the adjacent suprascapular nerve (arrow) based on detection of blood flow signals in the artery
HH
HH
Gl
a
TMj
b
Deltoid
Tm
Tm
Hm
c
d
Fig. 6.55a–d. Axillary nerve and posterior circumflex artery. a Oblique sagittal 12–5 MHz US image obtained over the axillary
recess of the glenohumeral joint demonstrates the inferior fibrocartilaginous labrum (white arrows) between the humeral head
(HH) and the bony glenoid (Gl). In proximity to these structures, the posterior circumflex artery (arrowhead) and the axillary
nerve (curved arrow) are displayed. b Long-axis 12–5 MHz US image of the axillary nerve (curved arrows) along its course
through the axilla. Note the relationship of the nerve with the posterior circumflex artery (arrowhead) and the deep teres major
muscle (TMj). Sagittal c gray-scale and d color Doppler 12–5 MHz US images obtained over the posterior humeral metaphysis
(Hm) demonstrate the axillary nerve (curved arrow) and the adjacent posterior circumflex artery (arrowhead) as they course
superficial to the bone, below the teres minor muscle (Tm) and deep to the deltoid. The inserts at the upper left side of the figure
indicate respective transducer positioning
Shoulder
supraclavicular, infraclavicular and axillary regions
(Yang et al. 1998; Sheppard et al. 1998; Apan et
al. 2001; Retzl et al. 2001; Martinoli et al. 2002;
Demondion et al. 2003). The US examination of
brachial plexus nerves is based on detection of some
anatomic landmarks in the neck, including bones
(roots), muscles (trunks) and vessels (divisions and
cords). After exiting the neural foramina, the roots
pass between two prominent apophyses of the transverse processes of the cervical vertebrae – the anterior and posterior tubercles – in close relationship
with the vertebral artery and vein (Fig. 6.56). Each
root emerges as an individual (monofascicular)
hypoechoic structure, an appearance quite different from that of nerves in the extremities, which
are composed of clusters of hypoechoic fascicles.
Coronal planes are able to depict the nerve roots in
the paravertebral area using the same longitudinal
scan for the study of the vertebral artery and vein
as a landmark (Fig. 6.57a,b). In these planes, the
picture of the vertebral vessels is obscured at regular
intervals by the acoustic shadowing from the anterior tubercles of the transverse processes. Moving
the transducer slightly posteriorly, the vessels disappear and the roots appear as elongated hypoechoic
images exiting the neural foramina, each of which is
located over the costotransverse bar of the vertebra
(Fig. 6.57c,d). Nevertheless, transverse planes are
ideal to depict the relationship of the roots with the
transverse processes at any given level. Based on the
peculiar appearance of the transverse process of C7,
in which the posterior tubercle is absent, US is able
to assess the level of the nerve roots (Martinoli et
al. 2002). For this purpose, scanning first reveals the
C7 level and then moves either up or down on axial
planes. The C7 root is detected in the same plane as
the C7 vertebra is bordered by the posterior tubercle
only (Fig. 6.58a–d). Shifting the transducer upward,
the C6 vertebra is recognized due to the presence
of prominent anterior and posterior tubercles: the
C6 root appears as a hypoechoic structure held
in between them (Fig. 6.58e–h). The transverse
processes of C5 have basically the same shape as
those of C6 and can be identified as successive
steps cranial to the C6 level by taking into account
the number of transverse processes encountered
while sweeping the transducer cranially from C7.
From the anatomic point of view, the higher the
level, the smaller the space between the tubercles.
Then, moving the transducer downward from
C7, the lateral aspect of the T1 vertebra is flat
without any tubercle; at this level, the C8 root can
be appreciated near the foraminal outlet. More
caudally, identification of the T1 root is not always
feasible due to problems of access related to the too
deep location of the intervertebral foramen between
the T1 and T2 vertebrae. The T1 root shows a curving
course below the first rib, and can be examined
by using an axial oblique plane of approximately
45°. In addition to determining whether a lesion is
preganglionic rather than postganglionic, or infraclavicular rather than supraclavicular, attributing
SternoCl
Thy
IJV
CA
LC
*
Esoph
1
2
3
Fig. 6.56. Normal brachial plexus: paravertebral area. Transverse 12–5 MHz US image over the left anterolateral neck demonstrates the main landmarks for identification of the nerve roots. Note the position of the left lobe of the thyroid (Thy), the
esophagus (Esoph), the common carotid artery (CA), the internal jugular vein (IJV) lying between the superficial sternocleidomastoideus (SternoCl) and the deep longus colli (LC) muscles. Deep to these structures, the lateral aspect of the C6 vertebra
shows a wavy hyperechoic contour, which delineates the vertebral body (1), the pedicle (2) and the transverse process (3), which
exhibits in turn two prominent anterior (asterisk) and posterior (star) tubercles. The C6 root (arrow) appears as a hypoechoic
image contained between these tubercles. The insert at the upper left side of the figure indicates transducer positioning
237
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S. Bianchi and C. Martinoli
*
*
a
v
a
b
c
d
Fig. 6.57a–d. Normal brachial plexus: paravertebral region. a,c Oblique coronal 12–5 MHz US images over the lateral neck with
corresponding b,d schematic drawings showing the position of the US transducer. a,b The vertebral artery (a) and vein (v) are
demonstrated along their long axis. Note that these vessels are obscured at regular intervals by the intervening acoustic shadowing of the anterior tubercles (asterisks) of the transverse processes. c,d Shifting the transducer slightly posteriorly (black arrow
in d), the vessels disappear and two nerve roots (open and white arrowheads) are appreciated as elongated hypoechoic images
exiting the neural foramina (open and white arrows), each of which courses over a costotransverse bar (rhombi)
a given level of nerve involvement is an important
component of the imaging report since the list of
possible clinical syndromes in a patient with brachial plexopathy is different according to the pattern
of the injured roots and trunks (e.g., upper partial:
C5, C6 [C7]; lower partial: C8, T1; complete: C5–T1)
(Narakas 1993). Sweeping the transducer down
to the interscalene region on short-axis planes, the
nerve trunks are visualized as they pass in between
the scalenus anterior and scalenus medius muscles
(Yang et al. 1998). Visualization of the trunks in
the interscalene space depends on the amount of fat
between these muscles, and a careful scanning technique is needed because nerve fascicles can easily
be confused with muscle fascicles. The upper and
middle trunks are more readily identified with US
(Fig. 6.59). They are arranged in series from superficial to deep and receive contributions from the C5
and C6 levels (upper trunk) and C7 level (middle
trunk). One has to consider that the progression of
the roots is anatomically constant down to the interscalene region, where they unite to form the three
trunks: upper (C5 and C6), middle (C7) and lower
(C8 and T1). Therefore, the ability of US to recognize
the root levels in the paravertebral area also reflects
on a confident identification of the trunks by simply
following the nerves from where these latter arise.
In the supraclavicular region, the nerves are visualized as a cluster of hypoechoic rounded images that
represent the divisions (Yang et al. 1998). The divisions follow, for the most part, the posterior aspect
of the subclavian artery, just over the straight hyperechoic appearance of the first rib and apical pleura
(Fig. 6.60) (Sheppard et al. 1998; Yang et al. 1998).
Crossing down the clavicle, in the infraclavicular
area, the nerve cords continue their course along
the axillary artery and behind the pectoralis minor
muscle (Fig. 6.61). An individual identification of
divisions and cords of the brachial plexus distal to
the interscalene region is less feasible on US because
these branches anastomose with each other in various combinations. Overall, we believe that the main
advantage of US in brachial plexus imaging is its
ability to follow up continuously each individual
component of the plexus through the lateral neck
by shifting the probe back and forth in short-axis
plane. Similar to other sites in the body, anatomic
variants of brachial plexus nerves and surrounding
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S. Bianchi and C. Martinoli
SA
SA
b
First Rib
L
L
a
c
Fig. 6.60a–c. Normal brachial plexus: supraclavicular region. a Oblique transverse 12–5 MHz US image over the supraclavicular
region shows brachial plexus divisions and initial parts of the cords as clusters of round hypoechoic fascicles (arrows) located
above and, for the most part, posterior to the subclavian artery (SA). Deep to these structures, the straight profile of the first
rib and the lung (L), which appears as a bright hyperechoic interface due to its air content, are also demonstrated. b,c Oblique
transverse b gray-scale and c color Doppler 12–5 MHz US images over the supraclavicular region. Doppler imaging may help
to identify nerves (arrow) in this region based on detection of blood flow signals from the adjacent artery. The insert at the
upper left side of the figure indicates transducer positioning
PMj
PMj
Pm
Pm
AA
a
b
Fig. 6.61a,b. Normal brachial plexus: infraclavicular region. Oblique transverse 12–5 MHz US images obtained under the clavicle
a over the major axis of the axillary artery (AA) and b immediately behind it. The cords of the brachial plexus (open and white
arrowheads) are visualized as elongated fascicular structures coursing around the axillary artery and deep to the pectoralis minor muscle (Pm). PMj, pectoralis major muscle. The insert at the upper left side of the figure indicates transducer positioning
tissues possibly predisposing to compressive neuropathy can be demonstrated with US, including
cervical rib, hypertrophied transverse process of
C7 and variations in the scalene muscles (Fig. 6.62).
Detection of a discrete arterial branch arising from
the subclavian artery and encroaching on the brachial plexus nerves in the supraclavicular region
is a normal finding. This blood vessel is the dorsal
scapular artery (Fig. 6.63).
In addition to brachial plexus nerves, US is
also able to image other nerves running in the lateral cervical region, including the vagus nerve
(Giovagnorio and Martinoli 2001), the recurrent
laryngeal nerve (Solbiati et al. 1985) and the spinal
accessory nerve (Bodner et al. 2002). The vagus
nerve (CN X), the main parasympathetic nerve to
the organs of the body, leaves the skull through the
jugular foramen and passes inferiorly in the posterior part of the carotid sheath, in the angle between
and posterior to the internal jugular vein and the
carotid artery (Fig. 6.64a). In this location, it can be
appreciated with US as a thin (<2 mm in cross-sectional diameter) vertically oriented cord-like structure containing three or four very small fascicles
(Fig. 6.64b) (Giovagnorio et al. 2001). Its secondary
branch, the recurrent laryngeal nerve, reaches the
Shoulder
SA
First Rib
a
b
c
Fig. 6.62a–c. Accessory cervical rib. a Anteroposterior radiograph in an asymptomatic subject demonstrates a cervical rib
(straight arrow) on the right and a hypertrophied transverse process (curved arrow) of the C7 vertebra on the left. The cervical
rib articulates with a prominent posterior tubercle of C7 and the first rib. b Transverse 12–5 MHz US image obtained in the
right paravertebral area demonstrates the close relationship between the C7 root (large arrow) and an abnormally prominent
posterior tubercle (narrow arrow). c Oblique transverse 12–5 MHz US image obtained in the right supraclavicular region reveals
the distal articulation (arrowheads) of the cervical rib as it bulges alongside the subclavian artery (SA) and the nerve divisions
(large arrow) of the brachial plexus to connect with the first rib
*
SA
*
SA
*
a
b
Fig. 6.63a,b. Dorsal scapular artery. a,b Oblique transverse a gray-scale and b color Doppler 12–5 MHz US images obtained in
the right supraclavicular region of an asymptomatic subject demonstrates an anomalous origin of the dorsal scapular artery
(asterisks) from the subclavian artery (SA). Soon after its origin, the artery passes among the brachial plexus nerves (arrows)
forming a cleavage plane between superficial (upper and middle trunks) and deep (lower trunks) clusters of nerve fascicles
IJV
Thy
IJV
CA
T
CA
a
b
c
Fig. 6.64a–c. Vagus and recurrent laryngeal nerves. a Schematic drawing shows the vagus nerve (arrow) inside the major neurovascular bundle, and behind the common carotid artery (CA) and the internal jugular vein (IJV). The recurrent laryngeal nerve
(curved arrow) courses more medially, along the tracheoesophageal groove and immediately posterior to the thyroid lobes. b
Transverse 12–5 MHz US image of the right neurovascular bundle shows the vagus nerve (arrow) as a very tiny structure characterized by a few hypoechoic fascicles surrounded by hyperechoic epineurium, between the common carotid artery (CA) and
the internal jugular vein (IJV). c Transverse 12–5 MHz US image over the right lobe (Thy) of the thyroid gland demonstrates
the small recurrent laryngeal nerve (curved arrow) as it ascends the neck alongside the trachea (T)
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S. Bianchi and C. Martinoli
posteromedial aspect of the lower pole of the thyroid
after looping the subclavian artery (on the right) and
the aortic arch (on the left). Then, it proceeds cranially in the tracheoesophageal groove to supply the
intrinsic muscle of the larynx (Fig. 6.64a). Using a
high-resolution transducers, small segments of this
nerve may be recognized in a few patients with lean
necks, deep to the thyroid (Fig. 6.64c) (Solbiati et
al. 1985). The spinal accessory nerve (CN XI) is a
motor nerve consisting of spinal and cranial roots
which leaves the skull base through the jugular
foramen and traverses the lateral cervical triangle,
a space bordered by the sternocleidomastoideus
muscle anteriorly, the trapezius posteriorly and the
clavicle inferiorly, to supply the trapezius muscle. Its
palsy causes limited shoulder elevation and retraction, the so-called drooping shoulder. The spinal
accessory nerve passes underneath the sternocleidomastoideus muscle and, in the lateral cervical triangle, it becomes superficial, coursing immediately
deep to the fascia and adjacent to superficial lymph
nodes. At this site, it may be injured during lymph
node biopsy or procedures of carotid surgery. US is
able to depict the normal nerve as a small (1 mm in
size) linear structure traversing the lateral cervical
triangle and can reveal its traumatic damage in the
appropriate clinical setting (Bodner et al. 2002).
6.5
Shoulder Pathology
Knowledge of the complex pathophysiology and
biomechanics underlying rotator cuff impingement
and shoulder instability is an essential prerequisite
for a correctly executed US examination and interpretation of the imaging findings.
6.5.1
Pathophysiologic Overview
6.5.1.1
Impingement and Rotator Cuff Disease
Rotator cuff disease is the commonest cause of shoulder pain and dysfunction in adults. It derives from a
wide range of pathologic conditions, including acute
and chronic trauma, arthritis and shoulder instability (Laredo and Bard 1996). Most tears, however,
occur in patients who lack a definite clinical history
of trauma or systemic disease. In these cases, rota-
tor cuff disease is believed to be secondary to local
causes. From the pathophysiologic point of view,
tendon ischemia was the first factor hypothesized
to play a causative role in the pathogenesis of rotator cuff disease (Codman, 1934). This theory was
supported by the histologic evidence of a relatively
hypovascular area in the supraspinatus tendon, the
so-called “critical zone”, which is located approximately 1 cm medial to the tendon attachment on the
greater tuberosity (Fig. 6.65a). Microangiographic
studies demonstrated that this zone is located at
the limit between the tendon vasculature deriving
from the myotendinous junction and that arising
from the teno-osseous junction of the supraspinatus
(Chansky and Iannotti 1991). The critical zone
is, therefore, prone to ischemia and more susceptible to develop degenerative changes. More recently,
tendon damage secondary to chronic contact of the
supraspinatus tendon with the undersurface of the
coracoacromial arch, the so-called “impingement
syndrome”, was proposed as the main causative
factor leading to rotator cuff tears (Neer, 1972). The
clinical success of combined procedures of rotator
cuff repair and anterior acromioplasty led to the
widespread acceptance of this hypothesis. A consensus is now emerging that the causes of rotator cuff
disease are manifold, including various combinations of extrinsic factors, such as morphology of
the coracoacromial arch, tensile overload, repetitive
overuse and kinematic abnormalities, and intrinsic factors, such as altered tendon vascular supply
(Soslowsky et al. 1997). The degenerative process
in the tendon substance may progress toward partial and complete tendon tears. As demonstrated
on autopsy studies, rotator cuff pathology becomes
more prevalent with increasing age. A disease prevalence of approximately 10% at 30 years, 50% at 60–70
years and 80% at 80 years has been reported and it
is well known that asymptomatic rotator cuff lesions
are not so uncommon, particularly in elderly subjects who do not realize the shoulder failure given
their reduced demands (Leach and Schepsis 1983;
Yamaguchi et al. 2001). Depending on the location of the contact, three main types of shoulder
impingement have been described: anterosuperior
(the most common), anteromedial and posterosuperior. As described above, the supraspinatus tendon
lies in the subacromial space between the humeral
head and the cover of the coracoacromial arch,
which is formed (from posterior to anterior) by the
anterior portion of the acromion and the acromioclavicular joint, the coracoacromial ligament and tip
of the coracoid. In normal states, the tendon glides
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S. Bianchi and C. Martinoli
a
b
c
d
e
f
Fig. 6.66a–f. Types of acromial morphology. a–c Schematic drawings of a sagittal view through the shoulder with d–f corresponding outlet view radiographs demonstrate a,d type I or flat acromion, b,e type II or curved acromion and c,f type III or
hooked acromion. Arrows indicate the different acromial shapes
Spurs on the acromial attachment of the coracoacromial ligament are also considered signs of shoulder
impingement. A poorly consolidated fracture of the
greater tuberosity can lead to an abnormal upward
displacement of the bony fragment and subsequent
narrowing of the subacromial space. Anterosuperior impingement may occur in the absence of
any evidence of anatomic abnormalities that may
explain it. Unlike impingement syndrome related
to alterations in the coracoacromial arch, these
cases occur in athletes involved in sporting activities which require overhead motion of the arm (e.g.,
volleyball, throwing) and are somewhat related to
glenohumeral joint instability (Jobe et al. 1989).
During anterior instability, repetitive overload leads
to some degree of anterior and superior translation
of the humeral head with secondary restriction of
the subacromial space and local attrition of the
supraspinatus tendon against the anterior acromion
and the coracoacromial ligament when the arm is
abducted and externally rotated. In general, these
patients have less advanced rotator cuff disease
(i.e., tendinosis, partial-thickness tears) and benefit
from therapy directed to the underlying instability, including strengthening of the rotator cuff. The
same often occurs in slender young females who
have weak scapular rotators. Once the impingement
syndrome is established, chronic mechanical microtrauma induce progressive tendon degeneration and
tearing as well as changes in the subacromial subdeltoid bursa. In the anterior impingement syndrome,
three stages of increasing tendon damage have been
described (Neer, 1972). Stage I is mainly appreciated in young adults in whom impingement leads to
subacromial bursitis and absent or minimal tendon
changes: this stage is usually reversible. Stage II is
characterized by progressive thickening and an
irregular appearance of the supraspinatus tendon
and the subacromial subdeltoid bursa as a result of
the degenerative process: surgery is usually considered (i.e., removal of the thickened bursa and release
of the coracoacromial ligament) if conservative
management fails. Stage III indicates progression of
tendon damage to partial- and full-thickness tears:
acromioplasty and cuff repair are often required.
Far less common than anterosuperior impingement, anteromedial impingement (subcoracoid
impingement) derives from encroachment of the
superior portion of the subscapularis tendon and the
long head of the biceps tendon against the tip of the
coracoid during maximal internal rotation and forward flexion of the arm (Gerber et al. 1985). Laxity
of the anterior capsule and ligaments and congenital anomalies of the coracoid process and the lesser
tuberosity seem to be implicated as predisposing factors. Finally, a third type of shoulder impingement,
the posterosuperior impingement (posterosubglenoid impingement) occurs as a result of pinching
of the rotator cuff at the junction of the supraspinatus and infraspinatus tendons, between the greater
tuberosity and the posterosuperior aspect of the glenoid rim, during maximal abduction and external
Shoulder
rotation of the arm (Walch et al. 1991). This kind
of impingement causes degenerative changes and
partial tears of the posterior supraspinatus tendon,
typically involving its undersurface.
6.5.1.2
Instability
Due to its peculiar anatomy, the shoulder joint is
inherently unstable. Several shoulder structures
may be involved in the pathogenesis of instability,
including bony surfaces, joint capsule, ligaments
and the fibrocartilaginous labrum (static restraints)
and the rotator cuff tendons (dynamic constraints).
In addition to anatomic factors, a combination of
other predisposing factors related to both developmental and acquired diseases, often combined with
one another, can be responsible for glenohumeral
joint instability. The degree of glenohumeral joint
instability ranges from subluxation to dislocation
and indicates that the humeral head slips out of its
socket during movements. In this setting, the clinician must realize whether a subluxation or dislocation has occurred and has to assess the state of the
anatomic structures responsible for joint stability
to establish a proper treatment. Based on its direction, shoulder instability can be defined as anterior,
posterior or inferior to the glenoid, or multidirectional (Zarins and Rowe, 1984). Anterior instability
accounts for approximately 96–98% of all shoulder
dislocations. Although often encountered in sub-
Acr
jects with a loose anterior capsule and ligaments,
anterior instability usually follows an acute injury
that weakens the para-articular structures responsible for joint stability. The mechanism associated
with anterior instability is abduction, extension and
external rotation. Recurrent subluxations or dislocations may occur even after trivial trauma. The
diagnosis of anterior instability is based on physical examination and plain films (Fig. 6.67). In most
cases, anteroposterior views are sufficient to detect
the anterior dislocation of the humeral head and
no additional projections are needed. Unlike dislocation, a subluxation of the humeral head may
be a subtle transient event that may be difficult to
recognize. Posterior instability may be secondary to
shoulder trauma and, when bilateral, is frequently
observed in seizures as a result of the stronger
convulsive contraction of the posterior muscles
(infraspinatus and teres minor) relative to that of
the subscapularis. The diagnosis is often missed
because this condition is uncommon (4% of all
shoulder dislocations) and may present with subtle
clinical and radiographic findings. Standard radiographs, including anteroposterior and lateral views,
may often be inadequate for detection of posterior
dislocation and additional projections, such as the
axillary view, may be required for this purpose.
However, these projections are not easily obtained
in the acutely injured patient. Approximately 50%
of posterior shoulder dislocations go unrecognized
and some authors have reported an average interval
from the injury to the diagnosis of 1 year, particu-
*
HH
a
b
Fig. 6.67a,b. Anterior shoulder instability. a Chronic anterior instability in an elderly patient. Note the anterior dislocation of the
humeral head (HH) relative to the acromion (Acr) and the coracoid (asterisk). b Anterior glenohumeral dislocation, subcoracoid
type. Anteroposterior radiograph demonstrates anterior displacement of the humeral head, which appears located inferior to
the coracoid process. A Hill-Sachs deformity is present (arrow)
245
246
S. Bianchi and C. Martinoli
larly in the case of a “locked” posterior dislocation
which occurs when the posterior glenoid causes an
impaction fracture on the humeral head preventing its repositioning (Hawkins et al. 1987). If not
recognized early, posterior dislocation can lead to
chronic joint stiffness, pain and reduced range of
motion. Chronic longstanding dislocations are most
often found in the elderly. In these cases, the prognosis is not good and the decision may often be to
leave the shoulder dislocated and attempt to regain
as much motion as possible with physical therapy or
the insertion of a shoulder prosthesis.
6.5.2
Rotator Cuff Pathology
Initially and for many years, investigators reported
contradictory results, either enthusiastic or poor,
in the ability of US to diagnose rotator cuff pathology (Mayer 1985; Mack et al. 1985; Middleton
et al. 1985, 1986b; Hodler et al. 1988, 1991; Burk
et al. 1989; Brandt et al. 1989; Soble et al. 1989;
Hall 1989; Ahovuo et al. 1989a,b; Miller et al.
1989; Drakeford et al. 1990; Vick and Bell 1990;
Misamore and Woodward, 1991; Nelson et al.
1991; Wulker et al. 1991; Wiener and Seitz, 1993;
Guckel and Nidecker 1997). In many cases, the
first studies made use of US criteria that nowadays
have either been refined or are no longer accepted,
examinations were performed with a scanning technique that has since been modified to improve visualization of the cuff, and old low-resolution equipments were employed. In the context of technological
improvements, higher resolution capabilities and
new criteria to diagnose rotator cuff tears, the current US technology is now increasingly able to reliably provide good accuracy in the assessment of rotator cuff tears (Teefey et al. 1999, 2004; Bouffard
et al. 2000; Leotta et al. 2000; Roberts et al. 2001;
Moosikasuwan et al. 2005). In addition, this technique allows the assessment of most of the stages of
rotator cuff disease and the classification of rotator
cuff tears based on the extent of tendon involvement,
size and location of the tear. As already described,
the supraspinatus is the rotator cuff tendon most
commonly involved by either partial- or full-thickness tears as a result of subacromial impingement.
In a large series of surgically proven rotator cuff
ruptures, isolated tears of the supraspinatus tendon
were found in 62% of cases, accounting for 18% of
partial-thickness and 44% of full-thickness tears
(Walch et al. 1999). Early degenerative changes and
tears of the supraspinatus are typically observed in
the anterior half of the tendon, just behind the long
head of the biceps tendon (Fig. 6.68a). The smallest forms of rotator cuff tears are partial-thickness
tears, which can in turn be located at either the articular (12%) or the bursal (5%) surface of the involved
tendon. Intrasubstance tears occur more rarely (1%).
If untreated, partial-thickness tears can enlarge to
become full-thickness tears (Fig. 6.68b). Overall,
one should consider that partial-thickness tears are
more common than full-thickness tears and those
involving the articular side of the rotator cuff are
slightly more common than those of the bursal side.
Beginning in the anterior third of the supraspinatus,
most tears then propagate in a posterior direction to
involve the middle and posterior tendon, eventually
in some cases causing complete supraspinatus rupture (Fig. 6.68c). In more advanced disease, other
rotator cuff tendons may additionally rupture as a
result of excessive tensile forces due to the altered
shoulder biomechanics related to the supraspinatus
tear (Fig. 6.68d). The involvement of other tendons
together with the supraspinatus has been reported
in an additional 30% of patients (Walch et al. 1999).
In these combined tears, the posterior extension of
a supraspinatus tear to the infraspinatus occurs in
approximately 20% of cases, whereas the anterior
involvement of the subscapularis from a supraspinatus tendon tear is less common and accounts for
approximately 10% of cases (Walch et al. 1999). As
the lesion expands anteriorly into the subscapularis,
disruption of the stabilizers of the biceps tendon
(i.e., rotator cuff interval structures) occurs. Isolated rupture of the subscapularis tendon occurs
in another 8% of cases: such ruptures are more
common in sport traumas due to forceful stretching on an abducted and externally rotated arm. On
the other hand, isolated rupture of the infraspinatus
is rare and occurs in the spectrum of posterior posterosuperior subglenoid impingement.
The classification of rotator cuff tears is somewhat confusing because different terms have been
inappropriately used with the same meaning. In
an effort to better understand the type of tendon
tear and to standardize the observations of various
examiners, the rotator cuff should be thought of in a
three-dimensional view. A tear must be considered
incomplete when it involves only a part of the tendon
width on short-axis planes (Fig. 6.68a,b). Incomplete
tears may be in turn subdivided into partial-thickness (Fig. 6.68a) or full-thickness (Fig. 6.68b) types
depending on whether they result in an abnormal
communication of the glenohumeral joint and the
Shoulder
a
b
c
d
Fig. 6.68a–d. Schematic drawings of a sagittal view through the shoulder illustrate the typical progression of a rotator cuff
tear. a Initially, a partial-thickness tear (dark gray) of the anterior supraspinatus tendon (light gray) occurs. This tear tends to
enlarge (arrows) in the vertical plane up to become b a full-thickness tear. Once established, a full-thickness tear expands in an
anterior and posterior direction (arrows) up to cause c complete rupture of the supraspinatus tendon. d In advanced disease, the
supraspinatus tendon tear may further expand either in a posterior direction (white arrow), involving the infraspinatus tendon,
or in an anterior direction (black arrows), involving the biceps and the subscapularis tendon, to create a massive tear
subacromial subdeltoid bursa. According to their
depth, partial-thickness tears may involve the
bursal side, the articular side or the midsubstance
(intrasubstance) of the tendon (Ellman 1990).
When a full-thickness tear involves the full width
of a tendon, it becomes a complete tear (Fig. 6.68c).
Then, it can become a massive tear as it spreads to
involve more than one tendon with a total width of
the affected cuff more than 3 cm (Fig. 6.68d).
6.5.2.1
Cuff Tendinopathy
Rotator cuff tendinopathy is thought to be an early
result of anterosuperior impingement (Neer stage II)
and, at first, affects the supraspinatus tendon along
with the subacromial bursa. The US appearance
of tendinopathy includes swelling of the affected
tendon and abnormal tendon echotexture with a
heterogeneous hypoechoic appearance (Fig. 6.69).
Tendon swelling can be appreciated with US as
either a focal or – most often – a diffuse increase in
tendon thickness (Farin et al. 1990). Because longaxis planes give a panoramic depiction of the tendon
as a whole, they are the most adequate to recognize
its thickening. Bilateral examination may occasionally be used to improve diagnostic confidence when
only small changes in the tendon size occur. In these
cases, care should be taken to evaluate the same
level on both sides because the supraspinatus tapers
toward the greater tuberosity and from anterior to
posterior. Dynamic scanning obtained by placing
the probe in the coronal plane over the lateral margin
of the acromion while the patient abducts their arm
in internal rotation may demonstrate difficult gliding of the thickened tendon and subacromial bursa
underneath the acromion (Read and Perko 1998).
Some thresholds in tendon size between the unaffected side and the affected supraspinatus (thickness
difference ranging from 1.5 to 2.5 mm) or a tendon
thickness greater than 8 mm have been proposed as
indicators of tendinopathy (Crass et al. 1988a). Similar to other applications of musculoskeletal imaging, we believe US findings in rotator cuff pathology
should be interpreted in the light of clinical data
rather than on the basis of differences in measurements. In fact, measurements are not so reliable and
their value is poor in the absence of clinical correlation. In addition, supraspinatus tendinopathy is
often associated with diffuse wall thickening of the
subacromial subdeltoid bursa and a small reactive
bursal effusion. In many instances, a cleavage plane
is lacking between these two structures and, therefore, it may be difficult to exclude the contribution of
the bursa when measuring the tendon thickness. As
247
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S. Bianchi and C. Martinoli
GT
a
b
Fig. 6.69a,b. Impingement syndrome with supraspinatus tendon abnormalities reflecting tendinosis. a Long-axis 12–5 MHz US
image over the supraspinatus demonstrates a hypoechoic and swollen tendon (straight arrows). The tendon insertion (curved
arrow) is more rounded and bulges over the greater tuberosity (GT). The subacromial subdeltoid bursa (arrowheads) can be
distinguished from the underlying tendon on the basis of its more hypoechoic appearance. b Arthroscopic photograph reveals
a reddish microvascular network (arrows) over the surface of the supraspinatus tendon reflecting intratendinous hyperemia
regards the abnormal echotexture in tendinopathy,
US findings seem to be related to subtle fibrillar
tears and areas of mucoid degeneration intermixed
with the reparative process occurring in the tendon
substance. Nevertheless, a definite pathologic correlation of these abnormalities is lacking in the
imaging literature because these patients are treated
conservatively. Mild cortical changes in the greater
tuberosity can also be observed.
6.5.2.2
Partial-Thickness Tears
Partial-thickness tears account for approximately
13–18% of all rotator cuff tears and occur in a
younger age group compared with full-thickness
tears (Walch et al. 1999). US detection of these tears
and their differentiation from focal tendinopathy is
often challenging because the appearance of the two
conditions may be similar. It must be noted, however, that the therapeutic approach is conservative
for both, so their differentiation is clinically worthless. On the basis of the US findings, we believe that
an accurate diagnosis of a partial-thickness tear
should be made when a true defect or cleft within
the tendon substance is clearly delineated on both
long- and short-axis planes. As previously stated,
partial tears most frequently affect the anterior third
of the supraspinatus tendon. The main US finding
is a localized hypoechoic area affecting only part of
the tendon thickness. Because the echogenicity of
the different tendon portions can vary depending
on the incidence of the US beam, a reliable diagnosis
of partial-thickness tears should be made only when
the area does not change its hypoechoic appearance
on short- and long-axis scans and while tilting the
transducer over the tendon (van Holsbeeck et al.
1995). The size of the tear must be measured on long
and short-axis planes and should be indicated in the
report as a measurement (in mm) or a percentage
of the tendon diameter (thirds of tendon thickness).
In our opinion, the second option is more practical
because it gives an estimate of the lesion with respect
to the tendon size. With reference to partial-thickness tears may have either a bursal or articular or
intratendinous extension. Bursal surface tears are
better visible on US and typically appear as hypoechoic concave defects located at the bursal surface of
the supraspinatus, in most cases close to the greater
tuberosity (Figs. 6.70, 6.71). Focal herniation of hypoechoic bursal fluid or hyperechoic peribursal fat
within the defect is often seen and represents a useful
sign for detecting such tears (Fig. 6.72). Bursal effusion is usually moderate and needs accurate scanning
technique for its detection: graded pressure with the
probe can make fluid herniation into the tear more
evident. In bursal tears, visualization of the integrity
of the deep articular fibers is always required so as
not to confuse these tears with full-thickness tears.
Articular surface tears are more common than bursal
ones, but are also more difficult to detect with US.
They appear as a discontinuity of the articular line of
the tendon filled with joint effusion and are associated with a normal insertion of the superficial bursal
fibers (Fig. 6.73). Often, they appear as a deep mixed
249
Shoulder
*
*
GT
a
b
Fig. 6.70a,b. Bursal-side partial-thickness tear of the supraspinatus tendon. a Schematic drawing of a long-axis view through
the supraspinatus tendon and b corresponding 12–5 MHz US image reveal a concave defect (dashed line) at the bursal surface
of the supraspinatus tendon in close proximity to the greater tuberosity (GT). The defect is filled with hypoechoic bursal fluid
(asterisks). Note the intact deep articular fibers (black curved arrow) of the tendon. 1, acromion; arrowhead, subacromial subdeltoid bursa; 2, supraspinatus tendon; straight arrow, glenohumeral joint cavity; white curved arrow, articular cartilage; 3, humeral
head. Correlative MR imaging of the same case is provided in the insert at the left bottom side of the US image
GT
a
b
Fig. 6.71a,b. Bursal-side partial-thickness tear of the supraspinatus tendon. a Schematic drawing of a long-axis view through the
supraspinatus tendon and b corresponding 12–5 MHz US image reveal detachment of the superficial tendon fibers (dashed line
an a; arrowheads in b) from their insertion into the greater tuberosity (GT). Note a subtle hypoechoic cleft separating the ruptured bursal fibers from the intact deep articular fibers (black curved arrow) of the tendon. 1, acromion; arrowhead, subacromial
subdeltoid bursa; 2, supraspinatus tendon; straight arrow, glenohumeral joint cavity; white curved arrow, articular cartilage; 3,
humeral head. Correlative MR imaging of the same case is provided in the insert at the bottom left side of the US image
hyperechoic and hypoechoic focus at the humeral
neck, due to the separation of the retracted distal
segment of the tendon from the surrounding intact
tissue, resulting in a new acoustic interface within
the tendon substance (Fig. 6.74) (van Holsbeeck et
al. 1995; Teefey et al. 1999; Bouffard et al. 2000;
Yao et al. 2004). Articular side tears are often accom-
panied by bone irregularities in the greater tuberosity. Intrasubstance tears may be appreciated as subtle
intratendinous longitudinal splits oriented from the
bony insertion proximally without exiting onto
either the bursal or the articular side of the tendon.
They appear as thin fluid-filled intratendinous lines
and must be assessed in their long and short axis to
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S. Bianchi and C. Martinoli
GT
GT
a
b
Fig. 6.72a,b. Bursal-side partial-thickness tears of the supraspinatus tendon. Two different cases. a Long-axis 12–5 MHz US
image over the supraspinatus tendon shows focal herniation of hypoechoic bursal tissue within the defect (arrowheads). Note
the thickened bursal walls (arrow) and the loss of the normal convexity of the peribursal fat at the site of the tear. GT, greater
tuberosity. b Long-axis 12–5 MHz US image over the supraspinatus tendon reveals hyperechoic peribursal fat filling a small
superficial defect (arrowheads) in the absence of local effusion.
*
GT
a
b
Fig. 6.73a,b. Articular-side partial-thickness tear of the supraspinatus tendon. a Schematic drawing of a long-axis view through
the supraspinatus tendon and b corresponding 12–5 MHz US image demonstrate detachment of the deep articular fibers
(open arrow) of the tendon from their bone insertion. A small hypoechoic effusion (asterisk) is seen filling the tear. Note the
intact bursal fibers (black curved arrow) of the tendon and the irregular cortical outline (arrowheads) of the greater tuberosity
(GT). 1, acromion; arrowhead, subacromial subdeltoid bursa; 2, supraspinatus tendon; straight white arrow, glenohumeral joint
cavity; white curved arrow, articular cartilage; 3, humeral head. Arthro-CT imaging correlation of the same case is provided in
the insert at the bottom left side of the US image
GT
*
GT
*
a
b
Fig. 6.74a,b. Articular-side partial-thickness tears of the supraspinatus tendon. Spectrum of US appearances. a,b Long-axis 12–5
MHz US images over the supraspinatus tendon show an intratendinous triangular fluid-filled defect (asterisk) with its base
facing the cortical surface. The separation of the retracted distal segment of the tendon from the overlying intact tissue results
in new acoustic interfaces (arrowheads) within the tendon substance. GT, greater tuberosity. Arthro-MR imaging correlation of
the same cases is provided in the inserts at the upper right side of the US images
251
Shoulder
avoid pitfalls related to anisotropy and confusion
with focal tendinopathy (Fig. 6.75). In other cases,
these tears may be characterized by a linear highlevel echo surrounded by a hypoechoic halo of fluid
or edematous tendon, the so-called “rim rent” tears
(Fig. 6.76) (Bouffard et al. 2000). In a series of 52
shoulders with arthroscopic correlation, US had 93%
sensitivity, 94% specificity, 82% positive predictive
value and 98% negative predictive value for detecting partial-thickness tears of the rotator cuff (van
Holsbeeck et al. 1995). Another more recent study,
performed with high-end equipment in which the US
findings were controlled with arthroscopic findings,
reported 67% sensitivity, 85% specificity, 77% positive predictive value, 77% negative predictive value
and 77% accuracy in the diagnosis considering partial-thickness tears as true-positives and no tears
as true-negatives (Teefey et al. 2000a). Compared
with US, MR arthrography has a higher sensitivity
for depicting small partial-thickness tears, particularly those occurring on the articular side of the cuff
(Ferrari et al. 2002).
6.5.2.3
Full-Thickness Tears
Full-thickness tears extend from the bursal to the
articular surface of the tendon. As previously stated,
the term “full-thickness” may refer to either a complete (full-width) or an incomplete (partial-width)
tendon rupture (i.e., a tear located in the anterior
third of the supraspinatus which allows communi-
cation between the glenohumeral joint space and
the bursa is a full-thickness tear but not a complete tear because the middle and posterior third of
the tendon is unaffected). In general, full-thickness
tears have a greater extension than partial tears and
are, therefore, easier to be detected with US. A classification of full-thickness tears has been proposed in
both the radiographic and clinical literature (Lyons
and Tomlinson 1992). In small (<5 mm wide) fullthickness tears of the supraspinatus tendon, a thin
hypoechoic cleft can be seen connecting the joint
cavity and the bursa (Fig. 6.77). The identification
of these tears may not be easy because of the lack of
tendon retraction (the supraspinatus is maintained
in the correct position by its intact portions) and the
absence of changes in the inferior boundaries of the
deltoid and subdeltoid fat. A focal bursal thickening or a small amount of fluid collected just over
the lesion can increase the examiner’s confidence
that a lesion is present. In this regard, some authors
have even proposed performing the US examination after arthrography to obtain a better assessment of rotator cuff tears as a result of the induced
bursal-joint distension (Fermand et al. 2000; Lee
et al. 2002). Otherwise, small tears should always
be confirmed on both long- and short-axis planes
to avoid any confusion with the distal prolongation
of supraspinatus muscle tissue. In some cases, a differential diagnosis between a partial-thickness tear
and small full-thickness tear cannot be achieved
even with high-resolution transducers. Larger fullthickness tears usually affect the anterior portion
of the supraspinatus tendon at the level of the criti-
b
a
GT
a
b
Fig. 6.75a,b. Intrasubstance partial-thickness tear of the supraspinatus tendon. a Schematic drawing of a long-axis view through
the supraspinatus tendon and b corresponding 12–5 MHz US image display a hypoechoic longitudinal split (void arrow) oriented from the tendon insertion into the greater tuberosity (GT) proximally with integrity of the more external bursal (b) and
articular (a) fibers. 1, acromion; arrowhead, subacromial subdeltoid bursa; 2, supraspinatus tendon; white arrow, glenohumeral
joint cavity; white curved arrow, articular cartilage; 3, humeral head
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S. Bianchi and C. Martinoli
a
GT
b
Fig. 6.76a,b. Rim rent tear. a Long-axis 12–5 MHz US images of the supraspinatus tendon with b arthro-CT correlation demonstrate a small hypoechoic triangular defect (open arrowheads) with a central hyperechoic line (arrow) extending from the
tendon insertion proximally. These tears relate to a minimal detachment of fibers from the greater tuberosity (GT) and should
not be confused with linear intratendinous deposits in calcifying tendinitis. In most cases, they affect the articular fibers of the
anterior supraspinatus tendon and are associated with irregularities (white arrowhead) in the underlying bone
a
b
c
d
Fig. 6.77a–d. Small full-thickness tear of the supraspinatus tendon (perforation). a,c Schematic drawings of the supraspinatus
tendon depicted in its a long-axis and c short-axis views with b,d corresponding 12–5 MHz US images demonstrate a thin
funnel-like hypoechoic cleft (void arrows) connecting the deep glenohumeral joint cavity with the superficial bursa. In d, note
slight focal thickening (open arrowheads) of the bursal walls in relation to the tear. In doubtful cases, this sign can enhance the
diagnostic confidence of the examiner that a tear is present in the supraspinatus tendon. Arthro-CT imaging correlation of the
same case is provided in the insert in d. 1, acromion; arrowhead, subacromial subdeltoid bursa; 2, supraspinatus tendon; GT,
greater tuberosity; straight arrow, glenohumeral joint cavity; white curved arrow, articular cartilage; 3 and HH, humeral head
Shoulder
*
GT
*
GT
a
b
Fig. 6.78a,b. Non-retracted full-thickness tear of the supraspinatus tendon. a Long-axis 12–5 MHz US image over the posterior supraspinatus tendon with b T2-weighted MR imaging correlation displays a linear fluid-filled defect (arrowhead) with
minimal proximal tendon retraction (arrow), leaving a small tendon remnant (asterisk) attached to the distal tip of the greater
tuberosity (GT)
cal area (Fig. 6.78). When the tear is localized in
this area, the posterior supraspinatus can appear
completely normal. In these cases, US proved to be
accurate for predicting the size of the tear. Longaxis scans may be used to measure the amount of
retraction of the torn tendon end from the greater
tuberosity, whereas an estimate of the tear width can
be obtained on short-axis scans from the distance
between the torn tendon ends (Fig. 6.79) (Farin et
al. 1996b). The accuracy of these measurements is
worse in large-sized tears (Teefey et al. 2005), and
may be somewhat related to shoulder positioning
(Ferri et al. 2005). When scans using the Crass and
Middleton positions were compared with the operative findings, the former appeared to reflect more
accurately the true size of full-thickness tears in the
long-axis plane, whereas both were equally accurate
in evaluating the tear size in the short-axis plane
(Ferri et al. 2005). Conversely, the Middleton position tended to overestimate, at any extent, the size
of the tear. It is conceivable that the two positions
can create a different tension across a cuff tear, thus
affecting its measured size. In particular, the component of internal rotation in the Middleton position could contribute to increased tension along the
tendon length and the subsequent overestimation of
tear size (Ferri et al. 2005).
The US appearance of full-thickness tears depends
on the amount of joint effusion. When a large effusion is present, the tear appears as a focal hypoechoic area due to the fluid that fills in the tendon
discontinuity (Figs. 6.80, 6.81). In these cases, graded
pressure with the probe may be helpful to distinguish the hypoechoic fluid from the tendon. When
the effusion is small, it tends to collect in the most
dependent portions of the bursa and the joint cavity,
thus not filling the tear. In these cases, the diagnosis is based on focal non-visualization of tendon
fibers. In the absence of effusion or tendon retraction, tilting the probe and pressing it over the tendon
can demonstrate the detachment of the fibers from
their humeral insertion. Full thickness tear lead to
a naked appearance of the greater tuberosity as the
bone is no longer covered by the retracted tendon
(Fig. 6.80). In these patients, care must be taken not
to mistake the deltoid muscle for the supraspinatus.
Among the indirect signs of supraspinatus tendon
tears, the most important include focal herniation
of the deltoid muscle and peribursal fat into the
space created by the tear (Fig. 6.82a,b). This sign is
more pronounced in full-thickness than in partialthickness tears and can be appreciated even better
when pressure is applied with the probe. In addition,
there may be prominent reflection of the US beam
at the interface of fluid and the articular cartilage,
a sign which is commonly referred to as the “uncovered cartilage sign” or the “cartilage interface sign”
(Fig. 6.82c,d). Although this latter sign can be seen
in large partial tears affecting the articular surface
of the supraspinatus, it is most frequently encountered in full-thickness tears when there is anechoic
fluid overlying the articular cartilage. One should
be aware, however, that this latter sign is subjective and can also be appreciated in normal states
(Jacobson et al. 2004). The occurrence of bone
irregularities in the profile of the greater tuberosity is an important finding to be routinely sought
because it is not simply related to aging but also sig-
253
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S. Bianchi and C. Martinoli
*
*
1
a
c
bt
2
b
d
Fig. 6.79a–d. Size assessment of a supraspinatus tendon tear. a Long-axis and b short-axis 12–5 MHz US images of a full-thickness tear of the anterior supraspinatus tendon (asterisks) with c,d schematic drawing correlations showing transducer positioning demonstrate the amount of tendon retraction (1) and the width of the tear (2) as indicated by the distance (white lines)
between the gray vertical bars. The ovoid intra-articular portion of the biceps tendon (bt) may help the examiner to establish
that the affected portion of the tendon is the mid-anterior one
a
b
Fig. 6.80a,b. Large full-thickness tear of the supraspinatus tendon. a Schematic drawing of a long-axis view through the supraspinatus tendon and b corresponding 12–5 MHz US image demonstrate a large fluid-filled defect (asterisk) in the region of
the tear, where the tendon once inserted on the greater tuberosity (GT). Note the naked appearance of the greater tuberosity
and the retracted rotator cuff tissue (open arrow) which overlies the humeral head. 1, acromion; arrowhead, subacromial subdeltoid bursa; 2, supraspinatus tendon; white straight arrow, glenohumeral joint cavity; white curved arrow, articular cartilage;
3, humeral head
Shoulder
Deltoid
a
b
Fig. 6.81a,b. Full-thickness tear of the supraspinatus tendon. a Short-axis 12–5 MHz US image over the middle third of the
supraspinatus tendon with b T2-weighted MR imaging correlation display a large fluid-filled full-thickness tear (arrow). Slight
pressure applied with the transducer over the tear causes herniation (arrowheads) of hypertrophied bursal tissue into the defect
with loss of the normal convexity of the cuff and peribursal fat
GT
a
b
GT
c
bt
d
Fig. 6.82a–d. Deltoid herniation and uncovered cartilage sign. As in Figure 6.81, a long-axis 12–5 MHz US image over the
supraspinatus tendon with b schematic drawing correlation demonstrates herniation (large arrow) of the deltoid muscle and
hypertrophied bursal tissue into the space created by a full-thickness tear. The small arrow indicates tendon retraction. Note
the irregular cortical outline of the greater tuberosity (GT). c Long-axis and d short-axis 12–5 MHz US images reveal a small
full-thickness tear of the anterior supraspinatus tendon. The acoustic interface between the fluid in the tear (arrowheads) and
the surface of the articular cartilage produces a bright linear echo (curved arrow) which can be considered an indirect sign of
a rotator cuff tear. bt, biceps tendon
255
256
S. Bianchi and C. Martinoli
nificantly associated with rotator cuff tears, particularly with full-thickness supraspinatus tendon tears
(Wohlwend et al. 1998; Huang et al. 1999; Jiang et
al. 2002; Jacobson et al. 2004). This sign has been
found to be very important, as it has the highest
sensitivity and negative predictive value in the diagnosis of supraspinatus tendon tear (Jacobson et al.
2004). On the other hand, contradictory results are
reported in literature as to whether the US finding
of bursal fluid combined with a joint effusion may
be considered a specific predictive sign for a rotator cuff tear (Hollister et al. 1995; Arslan et al.
1999). This could be explained by the fact that bursal
or joint fluid is common in patients with shoulder
impingement even in the absence of a rotator cuff
tear (Jacobson et al. 2004).
Considering full-thickness tears as true-positives
and no tears as true-negatives, a recent study performed with high-end equipment in which the US
findings were controlled with arthroscopic findings
has reported 100% sensitivity, 85% specificity, 96%
positive predictive value, 100% negative predictive
value and 96% accuracy in the diagnosis (Teefey et
al. 2000a). In terms of study reproducibility, a low
level of interobserver variability was demonstrated
in the US detection, characterization and localization of rotator cuff tears by comparing the results
of two expert blinded observers in a group of 61
patients (Middleton et al. 2004). In the few discrepant cases, the disagreement concerned whether there
was a full-thickness or a partial-thickness tear or
whether a tear involved both the supraspinatus and
infraspinatus tendons or one or the other of these
tendons (Middleton et al. 2004b). Other diagnostic errors also occur in distinguishing tendinopathy
from partial-thickness tears (Teefey et al. 2005).
These data seem particularly important given that
US is generally regarded as one of the more operatordependent imaging techniques. On the other hand,
poor agreement is expected when there is marked
disparity between the operators’ experience levels
(O’Connor et al. 2005).
Compared with MR imaging, US has been demonstrated to have a comparable accuracy for identifying and measuring the size of full-thickness and
partial-thickness rotator cuff tears if performed by
an experienced examiner using high-end equipment (Jacobson 1999; Martin-Hervas et al. 2001;
Teefey et al. 2004). When the examiner has comparable experience with both imaging tests, the decision regarding which test to perform for rotator cuff
assessment does not need to be based on concerns
about accuracy (Chang et al. 2002; Teefey et al.
2004). Instead, it can be based on other factors, such
as the importance of ancillary clinical information
(regarding lesions of the glenoid labrum, joint capsule, or surrounding muscle or bone), the presence
of an implanted device, patient tolerance and cost
(Teefey et al. 2004).
6.5.2.4
Complete and Massive Tears
When a full-thickness tear spreads to involve the
full width of the supraspinatus, the tendon retracts
medially. The amount of tendon retraction depends
mainly on the age of the tear. In acute lesions, the
tendon is less retracted and its tip can still be detected
with US (Fig. 6.83a–c). In the more common chronic
ruptures, the tendon end disappears beneath the
coracoacromial arch as a result of involutional processes in the tendon substance and upward displacement of the humeral head (Fig. 6.83d,e). This condition can be promptly recognized with US. The main
US findings include nonvisualization of the tendon
and herniation of the deltoid, which shows a rectilinear or convex inferior margin facing the humeral
convexity. A broad area of the upper convexity of the
humeral head appears uncovered by the supraspinatus, the so-called “naked head” sign. Joint and
bursal fluid is often absent (Teefey et al. 2000b).
Especially in cases of mild retraction of the torn
tendon end, short-axis planes are essential to distinguish complete (full-thickness, full-width) from
incomplete (full-thickness, partial-width) tears of
the supraspinatus tendon (Fig. 6.84). A number of
possible pitfalls may mask or simulate a complete
tear of the supraspinatus tendon. Although most of
these pitfalls are easy to recognize and, therefore,
unlikely to present a diagnostic problem, others are
potentially confusing. Among them, the continuous layer of hypoechoic humeral cartilage resting
on a naked humeral head may create confusion with
an intact tendon (Fig. 6.85a). Similarly, massive calcific deposits in the supraspinatus tendon related
to calcifying tendinitis should not be mistaken for
a naked humeral head (Fig. 6.85b) (Middleton et
al. 1986a). Familiarity with these imaging findings,
coupled with the knowledge of the normal US anatomy of the rotator cuff, can facilitate recognition of
true disease and help avoid misdiagnosis.
After assessing a complete rupture of the supraspinatus tendon, attention should always be directed
to the infraspinatus and subscapularis tendons to
detect any possible posterior or anterior extension
258
S. Bianchi and C. Martinoli
*
Acr
HH
HH
a
Acr
*
b
Fig. 6.85a,b. Pitfalls in the diagnosis of complete supraspinatus tendon tear. a Long-axis 12–5 MHz US image over the cranial
aspect of the humeral head (HH) in a patient with a non-fluid-filled retracted tear of the supraspinatus tendon demonstrates a
thick hypoechoic layer (arrows) covering the cortical bone of the humerus. This is the articular humeral cartilage and should not
be mistaken for residual fibers of the supraspinatus tendon. Acr, acromion. b Long-axis 12–5 MHz US image over the supraspinatus tendon in a patient with calcifying tendinitis. Massive calcific deposits (asterisks) with well-defined posterior acoustic
shadowing occupy the supraspinatus tendon almost completely, giving it a hyperechoic appearance that possibly resembles a
convex bony surface. The thin hypoechoic band (arrowheads) which overlies the hyperechoic calcifications reflects bursal tissue.
A hypoechoic cleavage plane separates the humeral head (HH) from the intratendinous calcifications. This sign may be helpful
in making a correct diagnosis. Acr, acromion
of the lesion leading to a massive tear of the rotator cuff. Not uncommonly, a complete tear of the
supraspinatus can be seen expanding in the posterior direction to involve the infraspinatus tendon.
US findings of infraspinatus full-thickness tears
are often similar to those already described for
the supraspinatus (Fig. 6.86). Dynamic scanning
during internal and external rotation of the arm can
be helpful to demonstrate the torn infraspinatus
tendon detached from its insertion on the humeral
head. In these cases, atrophic changes in the infraspinatus muscle and a slight hypertrophy of the teres
minor muscle can be appreciated on posterior sagittal scans (Fig. 6.87). The examiner should be aware,
however, that infraspinatus muscle atrophy may
also occur with either an intact tendon as a result of
disuse in patients with full-thickness anterior cuff
tendon tears or suprascapular neuropathy (Yao and
Mehta 2002). Therefore, this finding does not imply
that the infraspinatus tendon is ruptured.
Due to the intrinsic interwoven structure of the
supraspinatus and infraspinatus tendons, some fullthickness tears of the supraspinatus may progress at
the posterior margin of the defect along a horizontal
cleavage plane causing a complex pattern of delamination (Fig. 6.88a). These horizontal tears are probably related to shearing stress forces generated by the
defect in the supraspinatus tendon. They consist of a
fissuration parallel to the plane of the articular side of
the tendon and appear as linear hypoechoic defects in
the middle thickness of the tendon. Detection of hori-
zontal tears has clinical relevance because it changes
the surgical approach. Unlike arthro-CT or arthroMRI, US does not easily reveal these tears. Changes
are usually subtle and experience is needed to correctly recognize this entity. When visible, horizontal
tears appear as focal linear hypoechoic defects in the
middle of the tendon (Fig. 6.89). In rare cases, insinuation of fluid into the tear can generate intramuscular cysts which appear as well-defined hypoanechoic
masses inside the belly of the supraspinatus or infraspinatus muscle (Fig. 6.88b). Tears of the teres minor
tendon are extremely rare and usually result from
acute shoulder trauma rather than caudal progression of a tear from the infraspinatus.
While tears of the infraspinatus tendon are almost
invariably associated with rupture of the supraspinatus, subscapularis ruptures can also be encountered as an isolated problem. Subscapularis tendon
tears are mainly related to acute traumatic lesions
produced with the arm abducted and in external rotation. Similar to other rotator cuff tendons,
complete tears of the subscapularis are revealed by
the absence of tendon fibers and the concavity of
the deltoid over the naked anterior surface of the
humeral head. Incomplete tears of the subscapularis tendon often involve the cranial and preserve the
caudal portion of the tendon (Fig. 6.90). This pattern
should not be mistaken for complete tears. For this
purpose, the morphology of the lesser tuberosity
as seen on sagittal planes may help to establish the
caudal limit of the tendon and avoid any confusion
Shoulder
HH
*
InfraS
Gl
a
b
Acr
S
*
c
d
Fig. 6.86a–d. Complete (full-thickness, full-width) tear of the infraspinatus tendon. a Transverse 12–5 MHz US image over the
posterior aspect of the glenohumeral joint demonstrates a fluid-filled rotator cuff tear (asterisk) producing herniation (open
arrows) of the deltoid muscle and peribursal fat at the site of the tear. Note the naked appearance of the humeral head (HH)
and the retracted end (arrowheads) of the infraspinatus tendon (InfraS) over the bony glenoid (Gl). b Corresponding schematic
drawing shows transducer positioning over the long axis of the ruptured infraspinatus tendon (IS). Tm, teres minor. c Sagittal
extended field-of-view 12–5 MHz US image over the posterior aspect of the glenohumeral joint with d T2-weighted MR imaging
correlation reveals fluid (asterisk) filling the infraspinatus tendon tear and the deltoid muscle overhead (open arrows) falling
into the tendon defect. At a more caudal level, note the ovoid appearance of the intact teres minor muscle (white arrows). S,
scapular spine; Acr, acromion
between incomplete and complete tendon ruptures
(Fig. 6.91). In addition, because of the peculiar insertion of the subscapularis on the lesser tuberosity and
relationships of this tendon with the long head of
the biceps tendon, subscapularis tears usuallycause
secondary instability of the biceps tendon. A more
detailed explanation of the mechanism of involvement of the biceps tendon will be given later.
Once a complete evaluation of rotator cuff tendons
has been performed, the size and location of the tear
has been determined and the degree of retraction
of the torn tendon has been assessed, the status of
the rotator cuff muscles should also be evaluated to
rule out possible hypotrophy and fat degeneration
(Sofka et al. 2004a). In fact, the orthopaedic literature has confirmed that recognition of muscle atro-
phy may contribute to a more precise choice of either
surgical or conservative treatment for patients with
rotator cuff tears, and may be useful for proving that
a post-traumatic lesion is not true but related to a
pre-existing degenerative state. Furthermore, presence of muscle atrophy following surgical repair
of a torn cuff may indicate that lack of functional
recovery is due to the state of the muscles and is not
related to unsuccessful surgery.
6.5.2.5
Intramuscular Cysts
Cysts located within the rotator cuff muscles are
essentially an imaging diagnosis as they are embed-
259
Shoulder
b
GT
a
c
Fig. 6.89a–c. Delamination of rotator cuff tears. a Long-axis 12–5 MHz US image over the infraspinatus tendon in a patient
with full-thickness tear of the posterior supraspinatus. A longitudinal hypoechoic cleft (arrows) in the middle thickness of the
infraspinatus tendon is observed reflecting delamination of fibers extending posteriorly to a supraspinatus tendon tear. GT,
greater tuberosity. b,c Oblique coronal arthro-CT images obtained over b the middle and c the posterior third of the supraspinatus tendon demonstrate an intratendinous horizontal cleavage plane (arrowheads) in continuity with the full-thickness tear
(arrow) of the supraspinatus
LT
c
a
*
LT
b
c
Fig. 6.90a–c. Incomplete (full-thickness, partial-width) subscapularis tendon tear. a,b Transverse 12–5 MHz US images obtained
over the anterior aspect of the humeral head (a upper level; b lower level) with c coronal T2-weighted MR imaging correlation
reveals a full-thickness tear of the upper portion of the subscapularis tendon. At the cranial level, no appreciable cuff tissue
is visible. Note the naked appearance of the lesser tuberosity (LT). A thin soft-tissue layer (void arrowheads) lies between the
humeral head and the deltoid: this represents thickened bursal tissue and should not be mistaken for cuff remnants. Shifting
the transducer slightly downward, some intact fibers (arrows) of the lower portion of the subscapularis are demonstrated. The
residual tendon has normal thickness and attachment into the lesser tuberosity. This finding indicates a full-thickness tear of
the subscapularis involving the cranial half of the tendon. In the MR image, note hyperintense fluid (asterisk) filling the wide
gap left by the torn tendon fibers and the intact lower tendon third (arrows). C, coracoid. White arrowheads, long head of the
biceps tendon
261
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S. Bianchi and C. Martinoli
* *
*
LT
a
b
Fig. 6.91a,b. Incomplete (full-thickness, partial-width) subscapularis tendon tear. a Sagittal 12–5 MHz US image obtained over
the short-axis of the subscapularis tendon with b sagittal arthro-CT correlation demonstrates a full-thickness tear of the upper two thirds of the subscapularis tendon. Note the flat appearance (dashed line) of the lesser tuberosity (LT), which curves
toward depth just caudal to the tendon insertion. This can be a useful landmark to establish the caudal limit of the tendon. In
this particular case, a wide fluid-filled cleft (asterisks) occupies the upper two thirds of the subscapularis insertion. Note some
echogenic fibers (arrow) of the subscapularis tendon which remain inserted onto the lowest aspect of the lesser tuberosity.
Compare Figure 6.90a with the normal short-axis appearance of the subscapularis shown in Figure 6.26a
ded within the muscle and, therefore, cannot be
recognized at either open or arthroscopic surgery.
At US, intramuscular cysts appear as well-defined
hypoanechoic masses with regular margins, located
within the bellies of these muscles (Fig. 6.92). Color
Doppler imaging does not usually reveal flow signals in the cystic wall. Once a cyst has been diagnosed, a careful search should be performed with US
to identify possible full-thickness or partial undersurface (horizontal cleavage) tears of the rotator
cuff tendons. In fact, a close association of these
cysts with rotator cuff pathology has been described
(Sanders et al. 2000). From the technical point of
view, abduction and external rotation of the shoulder
(ABER positioning) may be useful to better visualize
these cysts, possibly because this position removes
tension from the tendons and muscles of the cuff
and thus makes entry of fluid into the tendon tear
easier (Kassarjian et al. 2005). Although there
are no studies in the radiological literature dealing
with the pathologic findings of these lesions, their
pathogenesis is still debated. Two main hypotheses
seem possible. One theory is that they may represent
synovial cysts due to progressive accumulation of
articular fluid inside the muscle through a tendon
tear (Fig. 6.88b). It has been noted that the tendon
tear may not be located in the tendon of the muscle
containing the cyst but in the tendon of an adjacent
muscle, with the cyst developing as a result of a
delamination process (Kassarjian et al. 2005). On
the other hand, it has been proposed that these cysts
are ganglia arising from the rotator cuff tendons as a
result of a degenerative process. As with other cysts
around the shoulder, needle aspiration of intramuscular cysts can be attempted under US guidance.
6.5.2.6
Cuff Tear Arthropathy
In massive rotator cuff tears, the medial retraction
of the torn thinned tendons and the contraction of
the deltoid muscle cause upward displacement of
the humeral head resulting in an increased conflict
between the superior facet of the greater tuberosity
and the inferior aspect of the acromion (Fig. 6.93a).
Chronic local trauma leads to degenerative bony
changes such as sclerosis, subchondral cysts, spurring and thinning of the acromion and cortical
irregularities. In longstanding disease, subacromial changes are followed by a direct involvement
of the glenohumeral space related to the incongruity between the articular surfaces. The resulting
condition is referred to as eccentric (because of the
upward displacement of the humeral head) osteoarthritis or “cuff tear arthropathy” (Neer et al.
1983b). This state can be considered an end-stage
irreversible destructive arthropathy consisting of a
reduced or absent subacromial space, thinning and
loss of the articular cartilage at the lower third of
the humeral head and the superior aspect of the
glenoid cavity, inferior osteophytes of the humeral
head, a rounded and irregular greater tuberosity due
to abrasion during abduction of the arm with flat-
Shoulder
Acr
*
Acr
*
a
c
Cl
Acr
Acr
*
C
*
b
d
Fig. 6.92a–d. Intramuscular cyst. a Long- and b short-axis 12–5 MHz US images over the supraspinatus muscle (arrows) obtained by placing the transducer immediately posterior and medial to the acromioclavicular joint reveal an intramuscular cyst
(asterisk). In this particular case, the cyst was associated with an articular-side partial-thickness tear of the supraspinatus
tendon. Acr, acromion; Cl, clavicle. c Oblique coronal fat-suppressed Gd-enhanced T1-weighted and d sagittal proton density
MR imaging correlations. In c, contrast enhancement is seen in the muscle tissue surrounding the cyst
tening of the bicipital sulcus and a reduced thickness
of the acromion. In chronic longstanding disease,
the occurrence of a stress fracture of the acromion
can occur as a result of local trauma induced by the
humeral head (Hall and Calvert 1995). It has been
suggested that rotator cuff arthropathy may derive
from both mechanical factors and reduced cartilage
nutrition due to the increased volume of the articular cavity and subsequent decrease in intra-articular
pressure (Neer et al. 1983b).
The diagnosis of rotator cuff arthropathy basically relies on its radiographic appearance. We
believe standard radiographs are mandatory before
a US study because examining a patient with rotator cuff arthropathy with US as a first examination
may be a challenge, especially for the beginners. The
main US findings include a massive tear of two or
more rotator cuff tendons associated with a markedly reduced or absent subacromial space, loss of the
articular cartilage, a rounded and irregular greater
tuberosity due to abrasion during abduction of the
arm with flattening of the bicipital sulcus, a reduced
thickness of the acromion and marginal osteophytes
on the inferior humeral head (Figs. 6.93, 6.94). Joint
and bursal effusions may contain echogenic debris.
The close contact of the humeral head with the
undersurface of the acromion may make differentiation between these structures less immediate with
US. The best way to separate these structures is by
dynamic scanning on coronal planes (somewhat oriented along the long axis of the supraspinatus) over
the tip of the acromion while abducting the patient’s
arm in internal rotation. This maneuver may help
to distinguish the moving humeral head from the
stationary acromion and to appreciate the reduced
distance between them. An additional problem may
be related to the localization of the bicipital sulcus
which is, at least in part, effaced by the abrasions in
the greater tuberosity. This can lead to some technical problems even for the experienced examiner
because the sulcus is a main landmark for rotator
cuff evaluation. In the case of an intact subscapularis tendon, its identification may be helpful to localize the position of the flattened sulcus. A reduced
thickness of the acromion may also be observed.
These patients have a proximal migration of the
humeral head such that it contacts the undersurface of the acromion. This contact point functions
263
Shoulder
6.5.2.8
Postoperative Cuff
In the early stages, the impingement syndrome is
treated conservatively with restriction of activities, physical therapy, anti-inflammatory drugs
and, possibly, steroid injections in the subacromial subdeltoid bursa (Bokor et al. 1993). When
conservative treatment fails, surgery is indicated.
A basic knowledge of the type of surgical intervention performed and its extent is critical for the
examiner to reach a correct interpretation of the
US images. Before the examination, details of the
surgical intervention should always be collected
from the surgical reports or the patient’s records.
Generally speaking, the main surgical techniques
for impingement syndrome and rotator cuff disease
involve subacromial decompression and rotator cuff
repair or debridement. In patients with subacromial
impingement but without rotator cuff tears, subacromial decompression may be performed with either
an open procedure through an anterolateral deltoid
splitting incision or arthroscopy (Fig. 6.97a,b). The
open approach consists of excision of the anteroin-
Del
Del
Del
Del
HH
HH
a
b
Acr
c
ferior aspect of the acromion, including the distal
end of the clavicle, and resection or debridement of
part of the coracoacromial ligament (Fig. 6.97c,d). If
prominent osteophytes are present, the acromioclavicular joint and the distal 2.5 cm of the clavicle may
be removed. On the other hand, arthroscopic subacromial decompression is carried out by resecting the
anterior edge and inferior surface of the acromion
along with the subacromial subdeltoid bursa and
the subdeltoid fat. The coracoacromial ligament is
released and the distal clavicle is resected as well.
Combined open and arthroscopic approaches may
be used in the event of large full-thickness tears
of the rotator cuff. Although arthroscopy does not
require deltoid incision (leading to secondary weakness of the muscle), this technique is more often
associated with persistence or recurrence of pain
(procedure failure reported in up to 3–11% of cases),
as a result of insufficient excision of the acromion.
Other complications include progression of rotator
cuff tendinosis, residual or recurrent rotator cuff
tears and postoperative adhesions. In patients with
rotator cuff tear, the type of intervention mainly
depends on the location, thickness and severity of
Cl
d
Fig. 6.97a–d. Postoperative cuff: normal US findings. a,b Anterolateral deltoid splitting following open acromioplasty. Postsurgical coronal 10–5 MHz US images obtained lateral to the acromion while keeping the arm a abducted and b in neutral position. The deltoid (Del) tear produces a focal defect (arrows) in the normal convex muscle and causes herniation
(arrowheads) of subcutaneous fat within the tear. Note that the gap in the muscle enlarges with the arm in neutral position. HH,
humeral head. c,d Subacromial decompression including distal resection of the clavicle (Mumford procedure). c Postsurgical
coronal 10-5 MHz US image over the acromioclavicular joint with d radiographic correlation demonstrate an increased distance
(arrows) between the acromion (Acr) and the clavicle (Cl)
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S. Bianchi and C. Martinoli
the tear. In small partial-thickness tears, treatment
ranges from debridement of frayed tendon tissue
to a combined excision of the defect and repair of
the adjacent healthy margins of the cuff. In fullthickness tears, repair may be performed with
either a side-to-side suture (small tears) or tendonto-bone reattachment (large tears), both associated
with acromioplasty. Usually, these procedures are
carried out arthroscopically using three bursal
portals (anterior, lateral and posterior) or with a
mini open repair (least possible split in the deltoid,
preserving the acromial origin of the muscle). In
large full-thickness tears, a tendon-to-bone repair
is usually performed, reattaching the tendon at a
more proximal site (humeral neck) relative to the
greater (supraspinatus) or the lesser (subscapularis)
tuberosity (Figs. 6.98, 6.99). Nonabsorbable sutures
or metallic anchors (arthroscopic repairs) are used
for this procedure. Massive tears are, for the most
part, treated with debridement alone.
The diagnostic role of MR imaging of a shoulder
that has undergone surgical treatment is controversial due to sutures, suture anchors and osseous
changes that may alter signal intensities within the
acromion, humeral head and rotator cuff tissue
(Magee et al. 1997). US has the advantage that it is
unaffected by the presence of intraosseous hardware. Nevertheless, postoperative shoulder US may
be a challenge, especially if the operative details
are not available. At US examination, a repaired
supraspinatus usually appears much more heterogeneous than normal. The superficial tendon
boundaries may assume a slightly concave profile
a
b
when the supraspinatus is scarred and reduced in
volume. In addition, the bursal surface of the tendon
is often undefined as a result of bursal removal.
Intratendinous nonabsorbable suture material and
suture anchors may be seen as bright linear echoes
with faint reverberation artifact (Figs. 6.98c, 6.100a).
The examiner should be conscious that the retracted
torn tendon is often implanted in the humeral neck
rather than in the greater tuberosity. As a result,
some bare bone in the region of the greater tuberosity should not necessarily be regarded as a recurrent
tear. The most reliable US signs of a re-torn supraspinatus are: nonvisualization of the cuff because of
complete tendon avulsion and retraction under the
acromion, presence of a focal defect in the rotator
cuff, a variable degree of tendon retraction from
the surgical trough and detection of sutures floating freely in the fluid (Fig. 6.100b) (Crass et al.
1986; Hall 1986; Mack et al. 1988b; Prickett et al.
2003). In difficult cases, dynamic scanning may be
helpful to distinguish the impairment related to a
recurrent tear from adhesive capsulitis as well as to
assess the functional result of acromioplasty. Overall, the diagnostic accuracy of US for detection of
postoperative rotator cuff tears is similar to that for
imaging of shoulders that have not been operated
on (Mack et al. 1988; Furtschegger and Resch,
1988; Prickett et al. 2003). The most recent series
based on newer equipment, current US criteria for
tears and complete surgical validation of the results
reported 91% sensitivity, 86% specificity and 89%
accuracy for US identification of rotator cuff integrity postoperatively (Prickett et al. 2003).
c
Fig. 6.98a–c. Postoperative cuff: normal US findings. a Schematic drawing illustrates the modality of reattachment of the supraspinatus tendon to the greater tuberosity using a suture anchor (curved arrow) after a full-thickness cuff tear. b Anteroposterior shoulder radiograph demonstrates the metallic anchor (curved arrow) fixed at the level of the humeral neck. c Long-axis
12–5 MHz US image over the supraspinatus tendon reveals intratendinous sutures (arrowheads) and the drilled hole (arrows)
in the bone containing the anchor to which they are connected. US displays an intact tendon repair
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S. Bianchi and C. Martinoli
sites. Although the pathogenesis of calcifying tendinitis is not completely understood, this condition
seems to be related to hypoxic areas or metabolic
factors in tendons and is typically associated with an
intact rotator cuff. Local hypoxia is believed to lead
to fibrocartilaginous metaplasia that is turn produces the calcifications (Flemming et al. 2003). Four
stages of the disease can be recognized: precalcific,
calcific, resorptive and postcalcific (Uhthoff and
Sarkar 1989). In the resorption phase, the tendon
develops increased vasculature and the calcium
deposits are removed by phagocytes. There is significant correlation between acute pain attacks and
histologic evidence of calcium resorption. At the
time of diagnosis, patients may be asymptomatic or
may present with either acute or chronic pain. Typical symptoms include either subacute low-grade
shoulder pain increasing at night (formative phase)
or a sharp acute pain limiting shoulder movements
and seldom accompanied by fever due to rupture of
the calcification in the adjacent structures (resorptive phase). The diagnosis of calcifying tendinitis
is based on plain films (anteroposterior views in
internal, neutral and external rotation, outlet view)
which can accurately assess the size and location of
the calcifications. Radiographs can also detect calcific deposits inside the bursa and the occurrence of
focal erosions on the humeral head. Asymptomatic
rotator cuff calcifications do not require treatment.
In symptomatic cases, calcifying tendinitis can be
managed conservatively with physical therapy and
a short course of nonsteroidal anti-inflammatory
drugs. Complications are best treated with more
aggressive therapy including systemic steroids.
Evacuation of the calcific material can be obtained
by means of arthroscopy or US-guided puncture,
lavage and aspiration as described in Chapter 18.
At US, rotator cuff calcifications appear as intratendinous hyperechoic foci. Three main types
of calcium deposits can be identified with US
depending on the amount of calcium contained in
the deposit. Type I calcifications appear as hyperechoic foci with well-defined acoustic shadowing,
similar to gallstones (Fig. 6.101a). These calcifica-
a
b
c
d
Fig. 6.101a–d. Calcifying tendinitis: types of calcification. a Type I calcification appears as an intratendinous hyperechoic focus
(arrows) with well-defined posterior acoustic shadowing (arrowheads). This appearance correlates with the formative phase
of calcium deposition. b Type II calcification presents as a hyperechoic focus (arrows) with faint shadowing (arrowheads). c,d
Type III calcification may appear either as c a hyperechoic focus (arrows) with absent shadow or as d an undefined isoechoic
or slight hyperechoic structure (arrows) with mobile internal echoes, reflecting a semiliquid content. Both type II and type III
calcifications more likely correspond to the resorptive phase of calcifying tendinitis
Shoulder
tions correspond to the formative phase of calcium
deposition and account for approximately 80% of
cases. Type II and type III calcifications (“slurry”
calcifications) look like hyperechoic foci with a
faint (type II) or absent (type III) shadow and can
be referred to the resorptive phase, in which the
deposits are nearly liquid and can be successfully
aspirated (Fig. 6.101b,c). In symptomatic patients,
these deposits are more often associated with local
hyperemia at color Doppler imaging (Chiou et al.
2002). Often, semiliquid deposits are difficult to
diagnose because they appear nearly isoechoic
with the tendon (Fig. 6.101d). An oval area of fibrillar loss and small hyperechoic dots within the
affected tendon is the main criterion for detecting
them. The shape of the calcification is quite variable, ranging from well-defined chunks of calcium
to thin hyperechoic strands in the cuff (Fig. 6.102).
Del
*
These stripe-like deposits are typically located at
the preinsertional level (calcific enthesopathy) and
should not be confused for intratendinous partialthickness tears, such as rim rent tears. Although
standard radiographs can establish the tendon in
which the calcific deposit is located, US examination is valuable to determine which portion of the
tendon is affected, the distance of the calcification
from an arthroscopic landmark such as the biceps
tendon (particularly useful when the deposit does
not bulge over the tendon surface) and, most importantly, whether the calcification cause impingement
(Figs. 6.102a,d, 6.103). Dynamic examination can
reveal the impingement of the calcification against
the acromion while abducting the arm in internal
rotation. In the case of semiliquid deposits, local
compression and tilting the probe over the calcific
focus can induce movements of the fluid calcium.
*
a
d
b
e
c
f
Fig. 6.102a–f. Calcifying tendinitis: shapes of calcification. a–c Series of 12–5 MHz US images with d–f corresponding radiographs demonstrate the range of appearances of intratendinous calcifications in patients with calcifying tendinitis. a,d Bulky
ovoid calcification (asterisk) in the subscapularis tendon. Due to its large size, this deposit impinges on the deep surface of the
deltoid muscle. b,e Diffuse slurry calcifications (arrows) in the supraspinatus tendon. c–f Preinsertional stripe-like deposits
(large arrow) in the supraspinatus tendon
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Shoulder
6.5.3
Biceps Tendon Pathology
6.5.3.1
Biceps Tendinopathy
Tendinopathy of the long head of the biceps tendon,
including tenosynovitis and tendinosis, derives from
two main mechanisms: impingement and attrition.
In the first, the intracapsular portion of the biceps
is pinched between the humeral head and the coracoacromial arch during abduction and rotation of
the arm. The mechanism is similar to that leading
to supraspinatus impingement. In addition, if the
supraspinatus is torn, the humeral head is displaced
upward by the action of the deltoid so that the biceps
tendon is pulled by the humeral head and becomes
its main depressing structure (Fig. 6.108a). Chronic
tension related to this overload may be contributory
to tendon degeneration (Wallny et al. 1999). The
second mechanism derives from chronic conflict
between the intertubercular portion of the biceps
and a narrowed bicipital groove caused by local periostitis, osteophytes and bony irregularities in the
lesser tuberosity (Pfahler et al. 1999).
The main signs of tendinopathy are biceps tendon
hypertrophy related to edema and heterogeneous
echotexture with fissurations (Fig. 6.108b,c). These
abnormalities are maximal at the level of tendon
reflection over the humeral head and at the proximal portion of the bicipital sulcus. Color flow signals may be recognized around the swollen tendon
as well. In some cases, the extra-articular portion of
the biceps may appear normal and this finding may
be misleading if scanning does not systematically
include its intra-articular portion. In biceps tendin-
B
Hs
a
b
B
*
c
d
e
Fig. 6.107a–e. Intraosseous penetration of calcifying tendinitis of the pectoralis major. a Transverse 12–5 MHz US image over
the myotendinous junction of the long head of the biceps (B) demonstrates a swollen and hypoechoic pectoralis major tendon
(arrowheads) and a cortical erosion (arrows) at the enthesis. Hs, humeral shaft. b Frontal image from a delayed bone scintigram
shows a rounded focus (arrow) of marked increased radionuclide uptake at the level of the proximal right humeral shaft. c Anteroposterior radiograph obtained with internal rotation of the arm displays a faint calcification (arrow) adjacent to the humeral
cortex. d CT scan demonstrates the typical “comet-tail” calcification (arrowheads) within the distal pectoralis major tendon
and a well-defined cortical erosion of the enthesis (curved arrow), reflecting the intraosseous loculation of calcium from the
pectoralis tendon. B, long head of the biceps brachii. e Oblique sagittal STIR sequence shows marked hyperintense signal within
the soft tissues (arrowhead) and the medulla (asterisk) around the calcific focus (arrow). (Courtesy of Dr. Nicolò Prato, Italy)
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S. Bianchi and C. Martinoli
b
c
d
e
*
a
b
*
c
*
*
d
bm
*
*
*
e
Fig. 6.110a–e. Recent biceps tendon rupture. a Photograph shows distal retraction of the muscle belly (arrows) of the long head
of the biceps following tendon rupture, resulting in the characteristic Popeye appearance. b–e Series of transverse 12–5 MHz
US images obtained from proximal to distal at the levels (horizontal white bars) indicated in a show an empty sheath (asterisk)
just distal to the intertubercular sulcus. As the scanning plane proceeds distally, the retracted tendon end (arrow) is appreciated
and surrounded by increasing amounts of sheath effusion (asterisks). In e, note the retracted muscle belly (bm) encircled by
considerable intrafascial hematoma (asterisks)
GT
*
LT
SubS
a
b
Fig. 6.111a,b. Indirect US signs of biceps tendon rupture. a,b Transverse 12–5 MHz US images obtained over a the rotator cuff
interval and b the intertubercular groove. In a, the coracohumeral ligament (arrows) assumes a concave appearance following
disruption of the intra-articular portion of the biceps tendon. Note the intact subscapularis (SubS) and small amount of fluid
(asterisk) collected under the ligament instead of the biceps tendon. In b, the transverse humeral ligament (arrow) is seen
folding inward the intertubercular sulcus, within the space left free by the retracted biceps. GT, greater tuberosity; LT, lesser
tuberosity
Shoulder
Hs
a
Hs
b
B
c
Fig. 6.112a–c. Biceps tendon rupture and pectoralis major tendon. a Transverse 12–5 MHz US image obtained on the long axis of
the pectoralis major tendon (arrowheads) in a patient with biceps tendon tear demonstrates a hypoechoic effusion (curved arrow) instead of the myotendinous junction of the long head of the biceps. b Normal contralateral side showing the myotendinous
junction of the biceps (B) located just deep to the pectoralis insertion (arrowheads) Hs, humeral shaft. c Schematic drawing of
a coronal view through the anterior shoulder and the upper arm shows a lower position of the retracted myotendinous junction of the biceps relative to the pectoralis major tendon. In doubtful cases, placing the probe on the long axis of the pectoralis
tendon as a landmark may help the diagnosis of biceps tendon rupture
and white” appearance is often noted on transverse
scans (Fig. 6.113). Occasionally, there may be selfattachment of the ruptured tendon stump into the
groove without retraction and care should be taken
not to mistake it for a normal tendon. In these cases,
the reattachment of the torn tendon in a more distal
location may prevent muscle degeneration. The
muscle may exhibit a globular appearance as a result
of retraction but usually retains a normal internal
echotexture (Fig. 6.114a,b). Finally, in rare instances
biceps tendon tears may occur at the myotendinous
junction with a normal-appearing tendon inside the
groove (Fig. 6.114c–e). If the biceps tendon is examined without evaluating the muscle, such tears can
be missed completely. Although the US findings of
biceps tendon tears are multifaceted, the essential
point is to establish whether the tendon is intact
or torn: further information on position and echotexture of the tendon ends and the muscle does not
affect the therapeutic decision (surgical vs. conservative), which is essentially based on clinical findings
such as the patient’s age and activity. In general,
biceps tendon ruptures are significantly associated
with supraspinatus (96.2% of cases) or subscapularis
(47.1% of cases) tendon tears as a result of the same
impingement forces and tensile injuries (Beall et
al. 2003).
6.5.3.3
Biceps Tendon Instability
Due to its curvilinear course and reflection over
the humeral head, the biceps is intrinsically predisposed to instability. As a rule, the biceps does
not undergo medial subluxation or dislocation out
of the bicipital groove when the coracohumeral
ligament is intact. If the coracohumeral ligament
is torn, as may occur in association with anterior
supraspinatus tears, the biceps may dislocate over
the intact subscapularis. In such cases, the ruptured lateral part of the coracohumeral ligament
can be seen (Fig. 6.115a,b). Dynamic examination
during rotational movements of the shoulder can
reveal abnormally increased motion of the intraarticular portion of the biceps tendon, which is no
longer stabilized by the pulley formed by the coracohumeral and superior glenohumeral ligaments.
In these cases, abnormal stress forces can produce
early local degeneration with biceps tendon thickening and fissurations. More caudally, the biceps
may appear perched over the lesser tuberosity
(Fig. 6.115c). Careful scanning technique is needed
to image the subluxed long head of the biceps tendon
because instability occurs at first cranially, at the
intra-articular level. In addition, the slight medial
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S. Bianchi and C. Martinoli
SH
*
*
SH
LH
LH
a
c
*
* *LH
LH
*
b
d
Fig. 6.113a–d. Biceps tendon tear: spectrum of US appearances of the retracted muscle belly in relation to the age of the tear. a
Short-axis and b long-axis 12–5 MHz US images over the long (LH) and short (SH) heads of the biceps muscle in a patient with
a recent tear of the long head of the biceps tendon demonstrate hypoechoic fluid (asterisks) surrounding the belly of the long
head. The muscle appears retracted but exhibits similar echotexture to the adjacent short head. c Short-axis and d long-axis
12–5 MHz US images over the long (LH) and short (SH) heads of the biceps muscle in a patient with chronic longstanding tear
of the long head of the biceps tendon reveal marked echotextural differences between the two biceps heads with the long head
being much more echogenic. This change reflects atrophy of muscle fibers and fatty muscle infiltration
positioning that the tendon normally assumes as it
enters the bicipital sulcus should not be mistaken
for a pathologic finding. We believe that a proper
diagnosis of biceps tendon subluxation can be made
with US only when the tendon is seen overlying the
lesser tuberosity on transverse scans in which the
bicipital sulcus is clearly depicted. When the sulcus
is not clearly seen, the apparent subluxation of the
biceps tendon can be the result of either an incorrect
scanning technique or anatomic variations. In the
rare cases of intermittent instability, “to-and-fro”
displacement of the tendon out of the groove can
be seen. Dynamic scanning with the shoulder in
maximal external and internal rotation may help the
diagnosis (Farin et al. 1995). In these patients the
biceps groove should be accurately imaged on transverse planes to assess its shape (Farin and Jaroma
1996). A congenital shallow intertubercular groove
(<3 mm deep) with a flat medial wall predisposes
the long head of the biceps tendon to instability (see
Fig. 6.20c) (Levinshon and Santelli 1991). In rare
instances, dislocation of the biceps tendon can be
secondary to a combined tear of the lateral portion
of the reflection pulley and the transverse ligament
even if the subscapularis is normal. In these patients,
the biceps can dislocate superficial to the subscapularis (Fig. 6.116) (Patton et al. 2001; Bennett 2001).
When the biceps is subluxed, spurring in the lesser
tuberosity may contribute to worsening the tendinopathy as a result of attrition. In these cases, the
biceps may be markedly swollen and predisposed to
longitudinal splits, as already described. The pathogenetic mechanism of this abnormality is similar to
that occurring in the peroneus brevis at the ankle
as a result of intermittent anterior subluxation over
the lateral malleolus (see Chapter 16).
Disruption of the cranial third of the subscapularis tendon, either in isolation or associated with
supraspinatus tendon tear, is often associated with
biceps instability (Bennett 2001). When the cranial
third of the subscapularis is torn, the biceps tendon
tends to sublux superficial to it on cranial transverse
scans and to rest in a normal position on caudal
transverse scans (Fig. 6.117). When the subscapularis tear becomes complete, the biceps slips medially within the glenohumeral joint (Ptasznik and
Hennesy 1995; Farin et al. 1995; Farin 1996; Prato
et al. 1996). The US diagnosis of biceps tendon dis-
Shoulder
PMj
SH
LH
a
Hs
LH
Hs
d
b
c
Fig. 6.120a–d. Pectoralis major tendon tear. a Photograph of a patient complaining of pain and a palpable defect (arrow) in the
anterior wall of the axilla following an attempt to catch a heavy object. b Transverse 12–5 MHz US image over the defect reveals
hypoechoic fluid filling the bed (arrowheads) of the ruptured pectoralis major tendon. The injury occurred at the enthesis with
detachment of the tendon insertion into bone. Note the anterior displacement (arrow) of the myotendinous junction of the
biceps (LH) which appears surrounded by fluid. SH, short head of the biceps. Hs, humeral shaft. c More medially, a transverse
12–5 MHz US image demonstrates a heterogeneous retracted muscle (PMj), especially at its myotendinous origin (arrows)
fluid adjacent to the humeral cortex and along the
tendinous bed related to the hematoma can help
the diagnosis (Fig. 6.120b,c). The long head of the
biceps tendon and its myotendinous junction are
surrounded by fluid. As the tendon of the pectoralis
major is a stabilizer of the long head of the biceps
tendon distal to the humeral tuberosities, its rupture
leads to elevation of the biceps from the humerus
(Fig. 6.120d) (Martinoli et al. 2003). If the lesion
occurs at the distal myotendinous junction, US demonstrates a normal tendon insertion on the humerus
and swelling and a heterogeneous echotexture at the
tendon-muscle junction related to disrupted muscle
fibers and intervening hypoechoic hematoma, just
deep to the deltoid muscle. In complete ruptures, the
muscle belly is retracted medially and may exhibit
atrophic changes. With time, adhesions may form
a pseudotendon between the retracted muscle and
actual tendon stump (Rehman and Robinson, 2005).
When differentiation between partial and complete
tears is doubtful with US, MR imaging is an accurate means to confirm the diagnosis (Connell et
al. 1999; Lee et al. 2000; Carrino et al. 2000). Apart
from traumatic injuries, the pectoralis major and
minor muscles are the most common congenitally
absent muscles (Fig. 6.121). Patients typically have
a flattened chest wall with hypoplastic ribs and an
elevated nipple. Agenesis of these muscles is often
partial and may be part of a syndrome associated
with other anomalies: the Poland syndrome (Demos
et al. 1985). This syndrome is an autosomal recessive
condition with an incidence of 1:30,000 live births,
in which the absence of the pectoralis is unilateral
and associated with syndactyly and hypoplasia of
the ipsilateral upper extremity. US diagnosis of pectoralis agenesis is mainly based on the absence of a
muscle belly and tendon. Transverse planes over the
anterior chest wall and the myotendinous junction
of the biceps are obtained on both sides for comparison. In pectoralis agenesis, a fibrous remnant of the
tendon and muscle may occasionally be observed;
this finding should not be mislead the examiner
into thinking that a congenital absence of the muscle
does not exist.
There are few reports in literature dealing with
spontaneous rupture of the deltoid muscle. In the
reported cases, the injury occurred in patients with
chronic, massive rotator cuff tears and was in some
instances responsible for an acute onset of shoulder weakness. One of the possible causative factors
claimed to explain rupture or detachment of the
deltoid muscle is a history of repeated steroid injections for frozen shoulder and longstanding rotator
cuff tears (Allen and Drakos 2002). Because, in
patients with deltoid rupture and massive rotator
cuff tear, contraction of the intact deltoid can lead
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B
B
*
a
b
R
*
*
c
R
R
d
*
e
*
*
R
Fig. 6.121a–e. Pectoralis muscle agenesis. a Photograph of the thorax of a patient with congenital absence of the right pectoralis
major shows a flattened chest wall (arrowheads), which causes the nipple to be elevated, and the lack of the anterior axillary fold
(curved arrow). b,c Transverse 12–5 MHz US images over the b right and c left myotendinous junction of the biceps (B). On the
affected side, there is absence of the pectoralis tendon (arrowheads) and the biceps is shifted forward relative to the humeral
shaft (asterisk). d,e Sagittal 12–5 MHz US images over the d right and e left chest wall demonstrate complete absence of the
right pectoralis muscle (arrows). In d, note the subcutaneous fat which reaches the costal plane, made up of a combination of
ribs (R) and intercostal muscles (asterisks)
the humeral head to protrude through the defect (a
type of boutonnière) – most commonly in the anterior or middle third – humeral impingement on
the undersurface of the deltoid could be regarded
as another possible causative factor (Blazar et al.
1998; Bianchi et al. 2006). Upward displacement of
the humeral head may lead to it causing attrition at
different sites. If impingement acts on the anteromedial part of the acromioclavicular arch, it more
likely generates acromioclavicular cysts (Tshering
Vogel et al. 2005); if it affects the posterior part of
the acromioclavicular arch, it may lead to stress fractures of the acromion (Dennis et al. 1986). It is conceivable that a more lateral location of impingement
forces (possibly secondary to a small acromion size
or to a large humeral head) may cause weakening
and even tears of the deltoid attachment (Figs. 6.122,
6.123) (Bianchi et al. 2006). Detachment of the deltoid insertion from the anterolateral acromion is a
frequent surgical practice that improves exposure
during acromioplasty. Postoperative detachment of
the deltoid is a potential complication after this procedure. US can identify this condition, which can be
repaired surgically if recognized early.
Intramuscular injection through the deltoid
muscle is common practice to treat shoulder pain
and infection. Repeated injection of drugs, however,
can lead to fibrosis of the injection site, even evolving
into contracture status of muscles (injection myopathy). Deltoid muscle contraction is an uncommon,
often unrecognized, clinical entity which usually
involves the intermediate portion of the muscle, this
being the preferred site for intramuscular injection
(Chen et al. 1998). Clinical findings include a palpable fibrous cord within the deltoid muscle, skin
dimpling overlying the cord, wingling of the scapula
and a restricted range of shoulder motion, in particular limited adduction of the glenohumeral joint.
US is able to reveal multiple hypoechoic small-caliber fibrotic cords (diameter <1 cm) oriented along
the long-axis of the muscle (pattern I), reflecting the
initial stage of small focal fibrotic foci (Fig. 6.124)
Shoulder
a
b
Acr
HH
c
d
Fig. 6.122a-d. Disruption of the anterior two thirds of the deltoid muscle secondary to chronic humeral impingement in an
elderly patient with massive rotator cuff tear. a Photograph shows the prominence of the humeral head (straight arrows) on the
skin, which became increasingly visible during rotational movements of the arm. Curved arrow indicates the acromion. b Anteroposterior radiograph demonstrates marked superior translation of the humeral head with advanced signs of glenohumeral
osteoarthritis and acromiohumeral osteoarthritis. c Oblique coronal 12–5 MHz US image demonstrates a nearly absent subacromial space and considerable bulging of the humeral head (HH) external to the lateral edge of the acromion (Acr). There is
absence of the middle third of the deltoid muscle with the humerus approaching the superficial tissue planes of the superolateral
aspect of the shoulder. d Arthro-CT correlation reveals a disrupted deltoid muscle (arrowheads)
(Huang et al. 2005). As the injections continue or
the abnormality evolves over time, the small-caliber
cords may coalesce into larger hypoechoic areas
(pattern II) or even develop into calcified masses
(pattern III) (Huang et al. 2005). In advanced disease, treatment is based on distal release of the deltoid fibrous cords.
6.5.4.2
Adhesive Capsulitis (Frozen Shoulder)
Adhesive capsulitis, also referred to as “frozen
shoulder,” refers to an insidious syndrome of shoulder pain and restricted movement in the absence of
shoulder impingement and rotator cuff injury. The
patient generally complains of loss of the normal
shoulder range of motion, particularly arm elevation and external rotation. This condition tends to
occur in perimenopausal women and is associated
with diabetes mellitus, some drug treatments (i.e.,
isoniazide and barbiturates), trauma and prolonged
immobilization after reduction for shoulder dislocation. Although the pathophysiology of adhesive
capsulitis is unknown, hypervascular synovial proliferation followed by deposition of collagen and
formation of capsular adhesions is typically found
in these patients, leading to a reduced articular
volume and, as a consequence, to pain and severely
restricted joint motion. Treatment includes physiotherapy, steroid injections and closed manipulation
in the operating room. In refractory cases, hydrodilatation and anterior capsulotomy is indicated (Gam
et al. 1998).
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Shoulder
Acr
Acr
HH
HH
a
b
c
d
Fig. 6.125a–d. Adhesive capsulitis. Dynamic 12–5 MHz US scanning over the long axis of the supraspinatus tendons in a patient
with left adhesive capsulitis. US images are obtained with the arm a,b in a neutral position and c,d passively abducted while in
internal rotation. a,c right side; b,d left side. With this maneuver, US allows direct visualization of the relationships among the
acromion (Acr), humeral head (HH) and intervening supraspinatus tendon (open arrows) during active shoulder motion. On
the healthy right side, the passage (curved white arrow) of the supraspinatus underneath the acromion was unobstructed during
full shoulder abduction. Conversely, on the affected left side, the supraspinatus gliding showed a sudden block during abduction
movement. Different from that seen in impingement syndrome, the left supraspinatus appeared normal and the tendon passage
was abruptly and not gradually obstructed, with absence of subacromial soft-tissue abnormalities. After tendon blockage, the
patient tended to elevate (straight white arrow) the shoulder rather than to abduct the arm. The inserts at the right side of the
figure indicate transducer positioning
the rotator cuff interval and increased vasculature
depicted at color Doppler imaging around the intraarticular portion of the biceps tendon and the coracohumeral ligament (Fig. 6.126) (Lee et al. 2005).
Mild fluid distension of the biceps tendon sheath and
the subscapular recess are also seen. Nevertheless,
these signs are operator- and equipment-dependent and, for the most part, difficult to quantify. In
doubtful cases, MR imaging and MR arthrography
are valuable to diagnose this condition (Mengiardi
et al. 2004).
6.5.4.3
Glenohumeral Joint Instability
Although the value of US in assessing glenohumeral
joint instability is poor, this technique can incidentally detect a variety of instability injuries affecting the glenoid labrum and the bone (Rasmussen
2004). In anterior shoulder instability, the main
criteria for anterior labral tear are an enlarged (>2
mm) hypoechoic zone at the base of the labrum,
a hypoechoic cleft within an otherwise homogeneous labrum, a truncated, eroded, frayed, irregular
shape or absence of the labrum and an abnormal
motility of the labrum when dynamic scanning is
performed; altered labral echogenicity seems to
be an inaccurate finding (Fig. 6.127) (Loredo et
al. 1995; Hammar et al. 2001; Schydlowsky et
al. 1998b; Rasmussen 2004). On the other hand, a
small altered labrum seems to indicate degenerative
changes (Schydlowsky et al. 1998c; Hammar et
al. 2001; Taljanovic et al. 2000). In patients with
acute traumatic or recurrent anterior shoulder dislocations, US has a reported 88–95% sensitivity and
67–70% specificity for the diagnosis of labral tears
(Schydlowsky et al. 1998b; Hammar et al. 2001;
Rasmussen 2004). Nevertheless, even using highend transducers, the anterior capsular complex (capsule and inferior glenohumeral ligament) cannot
be distinguished clearly from the anterior labrum.
Although some attempts have been made to assess
the capsular tightness during dynamic scanning, US
seems unable to reliably identify the discontinuity
of the anterior capsuloligamentous complex in cases
of traumatic avulsion of the capsule from its glenoid
insertion, so-called capsular stripping or shearing.
In contrast, fragmentation of the anteroinferior rim
of the glenoid, representing a Bankart lesion, may
occasionally be identified with US as a V-shaped
bony defect over the anterior aspect of the glenoid
289
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S. Bianchi and C. Martinoli
SupraS
Bt
C
HH
HH
G
Fig. 6.126. Adhesive capsulitis. Short-axis 12–5 MHz US image over the intra-articular portion of the biceps tendon
(Bt) in a diabetic patient with adhesive capsulitis demonstrates homogeneous hypoechoic soft tissue (arrows) filling the space of the rotator cuff interval and making the
ligament structures of the bicipital pulley undefined. Note
the supraspinatus tendon (SupraS). HH, humeral head; C,
coracoid
G
HH
a
c
HH
HH
b
G
G
d
Fig. 6.127a–d. Fibrocartilaginous labrum tears: spectrum of US appearances. Transverse 12–5 MHz US images over the posterior
aspect of the glenohumeral joint show different appearances of posterior labrum tears: a,b hypoechoic clefts (arrows) within
a homogeneous labrum (arrowheads); c enlarged hypoechoic zone (straight arrows) at the base of the labrum (arrowhead); d
complete absence of the labrum. HH, humeral head; G, bony glenoid
Shoulder
(Hammar et al. 2001). Overall, we believe that US
has a intrinsic limitations in the evaluation of the
fibrocartilaginous glenoid labrum. It may exclude
labral tears when the labrum appears normal. In
suspected abnormalities, MR and CT arthrography
are the most reliable and specific technique to confirm a labrum tear by depicting contrast material
extending into the labral defect.
A scanning technique for documenting the presence, direction and extent of glenohumeral translation has been described in patients with voluntary posterior shoulder subluxation or dislocation
(Bianchi et al. 1994). Although rare, this condition
is often unrecognized clinically and may be misdiagnosed as a frozen shoulder. In this technique, the
examiner stands behind the patient and acquires
transverse images over the posterior glenohumeral
joint. The distance between the dorsal bony glenoid
and the tip of the humeral head is measured at rest
and during subluxation. The patient is examined
in different positions (neutral, 90° flexion, abduction and external rotation), including the one in
which he/she perceives the shoulder has become
subluxed. The measured distances are compared
between the affected shoulder and the healthy one:
distances between 12 and 18 mm are indicative of
subluxation (Fig. 6.128). It is important, however,
to point out that assessment of associated intra-
articular lesions essentially depends on the use of
contrast-based imaging modalities (CT arthrography and MR arthrography). In posterior shoulder
dislocation, the relationship of the coracoid (anterior approach) or the posterior glenoid surface (posterior approach) with the dislocated humeral head
can be assessed and the distances between these
structures are measured without the need of painful
rotation or abduction of the arm using both anterior
and posterior approaches (Fig. 6.129) (Hunter et al.
1998; Bize et al. 2003). The distances measured in
the affected shoulder are compared with those in the
contralateral shoulder (care should be taken not to
misdiagnose a bilateral dislocation) and a difference
greater than 20 mm indicates dislocation (Bianchi
et al. 1994). Quantitative measurements performed
during dynamic US scanning have also been suggested for measuring increased laxity in patients
with anterior and multidirectional shoulder instability (Jerosch et al. 1989; Krarup et al. 1999) as
well as for assessing anterior and posterior glenohumeral translation in a selected series of swimmers (Borsa et al. 2005b) and professional baseball
pitchers (Borsa et al. 2005c). Based on these studies, dynamic US seems to be a promising means
for measuring glenohumeral joint laxity, replacing
stress radiography for this purpose (Borsa et al.
2005a).
Co
InfraS
HH
G
Fig. 6.128a–d. Posterior subluxation of the
humeral head. a,b Axillary views and c,d corresponding 12–5 MHz US images over the posterior glenohumeral joint in a patient with voluntary shoulder instability. a,c During subluxation, the humeral head (HH) is more exposed
and posteriorly positioned (arrow) with respect
to the level of the bony glenoid (G) indicated
by the dashed line. b,d Same images obtained
after voluntary relocation of the shoulder show
the exact apposition of the humeral head (HH)
with respect to the glenoid (G). InfraS, infraspinatus tendon; Co, coracoid. US can help to
confirm that the subluxation is in a posterior
direction
a
c
Co
InfraS
G
b
d
HH
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S. Bianchi and C. Martinoli
Co
Co
*
Bt
Bt
HH
HH
Gl
a
Gl
b
c
d
Fig. 6.129a–d. Posterior shoulder dislocation. a Transverse 10–5 MHz US image over the anterior aspect of the glenohumeral
joint with b corresponding CT scan in a patient presenting with a clinical history of seizures and inability to move the arm
shows posterior displacement (curved arrow) of the humeral head (HH), leaving the surface of the anterior half (arrowheads)
of the glenoid (Gl) uncovered. There is a small effusion (asterisk) inside the subscapularis recess. Note the increased distance
between the humeral head and the coracoid (Co). The biceps tendon (Bt) is normal. c Transverse 10–5 MHz US image over the
posterior aspect of the glenohumeral joint reveals an abnormal backward prominence of the convex humeral head (HH) relative
to the glenoid (Gl). d Correlative anteroposterior radiograph demonstrates a fixed posterior shoulder dislocation characterized
by elevation of the humeral head, lack of visibility of the glenohumeral joint space and detection of two parallel lines of cortical bone visible on the medial aspect of the humeral head: the medial one (arrows) corresponding to the glenoid outline, the
lateral one (arrowheads) to an anterior impaction fracture
A variety of surgical procedures, both open and
arthroscopic, can be used to repair the capsulolabral complex and to thicken and tighten the glenohumeral ligaments in patients with post-traumatic
glenohumeral join instability (Mohana-Borges et
al. 2004). Detailed description of these procedures is
beyond the scope of this chapter. In the postoperative setting for glenohumeral instability, however,
suture materials and anchors used for fixation along
the capsuloligamentous complex can be visualized
with US (Fig. 6.130).
6.5.4.4
Humeral Head Fractures
Despite its limitations in assessing bones, US can
accurately detect the humeral head injuries which
accompany glenohumeral joint instability, including the Hill-Sachs and McLaughlin fractures and
avulsions of the tuberosities. The Hill-Sachs lesion
is a depressed intra-articular compression fracture
located on the posterolateral aspect of the humeral
head typically observed after episodes of anterior
glenohumeral dislocations. It can be regarded as a
hallmark of anterior glenohumeral joint dislocation
because it occurs in up to 47% of patients after the
first episode of dislocation and up to 100% in patients
with recurrent disease (Resnick et al. 1997). The
pathomechanism of Hill-Sachs fracture consists of
a powerful contraction of the para-articular muscles
that pull the humeral head against the anteroinferior
glenoid rim (Calandra et al. 1989; Resnick et al.
1997). The size and location of the fracture must be
evaluated because a large defect can facilitate new
episodes of dislocation. US has a reported sensitivity
of 91–100%, specificity of 89–100% and overall accuracy of 84–94% in detecting this lesion (Farin et al.
1996a; Pancione et al. 1997; Cicak et al. 1998). For
this purpose, the posterolateral aspect of the shoulder is examined with the transducer in transverse
planes. Deep to the infraspinatus tendon, the humeral
head at this level should have a smooth, curvilinear
surface. The Hill-Sachs lesion typically appears as a
wedge-shaped shallow defect of the hyperechoic bony
contour of the humeral head at the point where the
anterior portion of the infraspinatus inserts into the
greater tuberosity (Jerosch et al. 1990) (Fig. 6.131).
Its size and shape can be accurately assessed with US.
Dynamic examination with back and forth rotation
makes it possible to judge whether the lesion reaches
the glenoid cavity during movement and the extent to
which the motion of the limb is hindered. It is important to avoid confusion between the smaller and
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Shoulder
normal radiographs. When undisplaced, these fractures appear as a double discontinuity of the cortical
bone located at the notch between the humeral head
and the greater tuberosity (humeral neck) and over
the external slope of the greater tuberosity, often
at the junction of the humeral shaft and the anatomic neck of the humerus, suggesting an elevated
fragment (Fig. 6.133) (Patten 1992). In displaced
fractures, the uplifted fragment may be angled or
overlapping, and the supraspinatus tendon in continuity with it appears abnormally thickened and het-
GT
a
SupraS
erogeneous due to edema and contusion (Fig. 6.134).
In these cases, visualization of a well-demarcated
defect on the surface of the greater tuberosity can
avoid misdiagnoses with calcifying tendinitis. Avulsion fractures of the lesser tuberosity can also be
found in posterior shoulder dislocations as a result of
subscapularis traction (Fig. 6.135) (Ross et al. 1989;
Martinoli et al. 2003). Once a possible fracture of
the tuberosities is found, additional radiographic
views, particularly under fluoroscopic control, must
be obtained to confirm the US findings.
*
b
c
Fig. 6.133a–c. Minimally displaced greater tuberosity fracture. a Long-axis 17–5 MHz US image over the supraspinatus tendon
(SupraS) in a patient with anterior instability demonstrates a double discontinuity of the hyperechoic humeral surface at the
notch between the humeral head and the greater tuberosity (straight arrow) and over the external slope (curved arrow) of the
greater tuberosity (GT), suggesting an undisplaced greater tuberosity fracture. The initial plain film was negative. b Oblique
coronal fat-suppressed T2-weighted MR imaging correlation shows hyperintense signal (asterisk) at the greater tuberosity
reflecting post-traumatic marrow edema. c Follow-up radiograph performed 3 months later reveals subtle bony changes (arrowheads) around the greater tuberosity reflecting fracture healing
SupraS
SupraS
a
b
Fig. 6.134a,b. Greater tuberosity fracture: spectrum of US appearances. a,b Long-axis 12–5 MHz US images over the supraspinatus tendon in two patients with a an undisplaced and b an angulated fracture of the greater tuberosity, respectively. In a, subtle
elevation and fragmentation of the most superficial layer (open arrowheads) of the bony cortex (white arrowheads) of the greater
tuberosity creates two hyperechoic parallel lines (white and open arrowheads) resulting from a recent acute traction trauma by
the supraspinatus tendon (SupraS). In b, an avulsion fracture arising from the insertion of the supraspinatus tendon is observed,
just distal to the humeral articular surface. Compare the discontinuity of the hyperechoic humeral surface at the humeral neck
(straight arrow) and over the external slope (curved arrow) of the greater tuberosity with the undisplaced fracture shown in
Figure 6.133a. The fracture fragment is tilted and rotated following traction by the intact supraspinatus tendon (SupraS)
Shoulder
SubS
*
*
a
HH
b
Fig. 6.136a,b. Glenohumeral joint osteoarthritis. a Anteroposterior view shows typical radiographic findings of advanced disease,
including joint space narrowing, osteophytes (arrows) along the articular margins of the humeral head and the inferior margin
of the glenoid, upward translation of the humeral head with reduced subacromial space (white arrowhead), diffuse subchondral
sclerosis (black arrowheads) and multiple intra-articular osteochondral bodies (asterisks). b Transverse 12–5 MHz US image
over the anteromedial shoulder demonstrates an osteophyte (curved arrow) projecting just deep to the subscapularis tendon
(SubS). Note irregularities (straight arrow) in the cortical profile of the humeral cortex. HH, humeral head
portions of the glenohumeral joint, including the
axillary pouch, the biceps tendon sheath, the posterior glenohumeral recess and some bursal recesses
(i.e., lateral, subcoracoid bursa) which communicate
with the joint cavity as a result of a rotator cuff tear
(Fig. 6.137). Most intra-articular loose bodies appear
as hyperechoic images with posterior acoustic shadowing (Fig. 6.138). In some cases, however, a layer
of hypoechoic cartilage may be identified over the
echogenic interface corresponding to the subchondral bone (Bianchi and Martinoli 1999). The size
and position of the fragments can be reliably determined with US. Their exact number, in contrast,
cannot be established with certainty. Estimating the
size of loose bodies is important before planning
arthroscopic surgery because fragments that are too
large cannot be removed arthroscopically and may
make the procedure difficult and time-consuming.
However, such an assessment may also be problematic using standard radiographs, because the unossified portion of the fragment leads to an underestimation of its actual size. Differentiation between
loose bodies secondary to osteoarthritis, trauma
and osteochondromatosis is mainly based on clinical and radiographic findings. In general, US detection of innumerable loose bodies of nearly equal size
without joint space narrowing more likely reflects
osteochondromatosis, whereas identification of a
single fragment or a few fragments of different size
and appearance is more likely associated with an
osteoarthritis-related process or a post-traumatic
nature (Campeau and Lewis 1998). In idiopathic
synovial osteochondromatosis, the age range of the
affected patients is wide but, in most cases, disease
onset occurs in the fourth or fifth decades. Men are
affected more frequently than women. At US, different patterns may be noted depending on whether
the loose bodies contain cartilage alone, cartilage
and bone or mature bone (Fig. 6.139a,b). When
entirely cartilaginous (synovial chondromatosis),
the intra-articular nodules are hypoanechoic and
difficult to distinguish from surrounding effusion.
Furthermore, cartilage-containing masses of synovial chondromatosis may be difficult to differentiate from “rice bodies,” which are seen in patients
with chronic rheumatoid arthritis or tuberculosis
(Mutlu et al. 2004). At US, rice bodies may appear
as hypoanechoic spherules a few millimeters in size
(Fig. 6.139c,d). They may fill the subdeltoid bursa
and, in most cases, are distinguished with difficulty
from the adjacent hypoechoic synovial pannus due
to similar echogenicity. The pathogenesis of rice
bodies is different from that of loose bodies. In
the late stages of rheumatoid arthritis, rice bodies
seem to derive from chronic articular inflammation leading to formation of elongated synovial villi
which then become covered by fibrin and may snap
off, producing fibrin grains similar to polished rice
(Law et al. 1998; Reid et al. 1998). With increasing
age, rice bodies undergo a degree of organization
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Shoulder
a
b
Humerus
Humerus
c
d
Fig. 6.139a–d. Intra-articular bodies: spectrum of US appearances. a,b Primary synovial osteochondromatosis. a Transverse
12–5 MHz US image over the subacromial subdeltoid bursa with b T2-weighted MR imaging correlation demonstrates multiple small hyperechoic low signal intensity nodules (arrowheads) filling a distended bursa (arrows), consistent with synovial
osteochondromatosis. c,d Rice bodies in a patient with rheumatoid arthritis. c Coronal and d transverse 12–5 MHz US images
respectively obtained over the lateral pouch and the anterior dependent portion of the subacromial subdeltoid bursa show
multiple hypoechoic rounded filling defects (arrowheads) within an inflamed and enlarged bursa (white arrows) reflecting rice
bodies. Mild effusion is observed into the sheath of the biceps tendon (open arrow)
and may contain a core of mature collagen. Identification of rice bodies is clinically relevant as they are
a persistent reason for continuing synovial inflammation. Their removal is usually associated with
clinical improvement (Propert et al. 1982).
Among the degenerative arthropathies that typically involve the shoulder, there are a variety of conditions related to crystal deposition diseases, including
renal osteodystrophy, milk alkali syndrome, hypervitaminosis D and the so-called “Milwaukee shoulder syndrome”. This last condition, which is also
known as apatite-associated destructive arthritis,
hemorrhagic shoulder or rapid destructive arthritis
of the shoulder, consists of massive rotator cuff tear,
osteoarthritic changes, blood-stained noninflammatory joint effusion containing calcium hydroxyapatite and calcium pyrophosphate dihydrate crystals, synovial hyperplasia and extensive destruction
of cartilage and subchondral bone (Llauger et al.
2000). Osteophytes are not characteristic of Milwaukee syndrome. This destructive arthropathy
most commonly affects elderly patients, predominantly women, and manifests clinically as a rapid
progressive and destructive arthritis of the shoulder
with localized pain, swelling, variable limitation
of joint motion and joint instability. Occasionally,
there is rupture of the shoulder capsule with drainage of blood-stained fluid into the para-articular
soft tissues lasting for weeks or months (Fig. 6.140).
Radiographically, this condition resembles a neuropathy-like arthropathy with high-riding humeral
head. Pseudoarthrosis between the humeral head,
the coracoid and the acromion is commonly seen
(Nguyen 1996). Although US is able to demonstrate
a marked distension of the joint space by effusion
and echogenic debris reflecting synovial prolifera-
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S. Bianchi and C. Martinoli
a
b
c
Fig. 6.140a-c. Milwaukee shoulder. a Anteroposterior radiograph of the shoulder demonstrates advanced degenerative changes
of the glenohumeral joint associated with upward migration of the humeral head (arrow) related to rotator cuff tear and pseudoarthrosis (arrowhead) between the humerus, the coracoid and the acromion with mild subchondral bone sclerosis and little
osteophytosis. Note the calcific deposits in the lateral dependent portion of the bursa (curved arrow). b Coronal 12–5 MHz US
image obtained lateral to the acromion reveals extensive subdeltoid bursitis with prominent synovial fronding and signs of
rupture of the bursa into the subcutaneous tissue (arrows). c Photograph of the left shoulder demonstrates diffuse swelling and
ecchymosis related to drainage of blood-stained fluid into the para-articular soft tissues
tion and blood clots, calcified deposits, destruction
of the cartilage and osteolysis of the subchondral
bone, it is not reliable for differentiating this disorder from the more common osteoarthritis related
to rotator cuff disease. Therapy includes analgesic drugs and repeated arthrocentesis followed by
intra-articular steroid administration. In advanced
disease, shoulder arthroplasty may be considered.
In patients with chondrocalcinosis, US can depict
deposition of pyrophosphate crystals in the cartilage
of the humeral head (Peetrons et al. 2001). These
deposits appear as a blurry hyperechoic line on the
outer margin of the cartilage surface (Fig. 6.141).
Grossly echogenic thickening of the synovium,
especially prominent in the subacromial subdeltoid
bursa, para-articular nodules within the soft tissues
surrounding the cuff and deep bony erosions may
be observed in dialysis-related shoulder arthropathy reflecting amyloid deposition of ß2-microglobulin, which is an amyloid protein that is not filtered
by standard dialysis membranes (Kay et al. 1992;
Sommer et al. 2002; Cardinal et al. 1996; Llauger
et al. 2000; Slavotinek et al. 2000). US features of
shoulder amyloidosis are varied and may include a
heterogeneous and thickened rotator cuff, especially
involving the supraspinatus and the subscapularis
tendons (McMahon et al. 1991; Malghem et al.
1996). Based on these findings, US offers an early
diagnosis and should be a useful tool to follow up
the disease. In these patients, para-articular calcifications are often observed as a result of calciumphosphorus imbalance.
6.5.4.6
Inflammatory Arthropathies
As a result of a widespread involvement of synovial tissues, rheumatoid arthritis usually affects the
glenohumeral joint in association with the acromioclavicular joint and the synovial bursae around the
shoulder. Radiographically, rheumatoid arthritis
may cause uniform narrowing of the joint space,
marginal erosions, erosions of the greater tuberosity, osteophytes, flattening of the glenoid cavity and
sclerosis of apposing surfaces of the glenoid and
humerus and pseudowidening of the acromioclavicular joint related to reabsorption of the distal end of
the clavicle (Fig. 6.142a). US has proved able to reveal
synovitis both at the early stages of disease, when no
radiographic changes are yet evident (Alasaarela
and Alasaarela 1994; Chhem 1994; Alasaarela
et al. 1997; Gibbon and Wakefield 1999), and in
an asymptomatic population with arthritic shoulder
(Naranjo et al. 2002). This technique is used for the
evaluation of shoulder girdle arthritis in an attempt
to assess which synovial cavity is involved by the
inflammatory process, to differentiate between effu-
Shoulder
HH
a
b
Fig. 6.141a,b. Chondrocalcinosis. a Oblique coronal 12–5 MHz US image over the supraspinatus tendon with b radiographic
correlation demonstrates a continuum of fine hyperechoic spots (arrows) located in series within the hypoechoic articular
cartilage of the humeral head (HH), reflecting calcium pyrophosphate dihydrate crystal deposition disease
* *
HH
Gl
a
b
HH
c
HH
d
Fig. 6.142a–d. Rheumatoid arthritis. a Anteroposterior radiograph in a patient with longstanding disease shows confluent
marginal erosions and subchondral cysts (arrows) in the humeral head. b Transverse 12–5 MHz US image over the posterior
shoulder reveals a hypoechoic soft-tissue mass (asterisks) representing synovial pannus within the posterior recess. In addition
to this finding, there are irregularities in the posterior aspect of the humeral head (HH), consistent with bone erosions (arrows).
Gl, glenoid. c,d Transverse c gray-scale and d color Doppler 12–5 MHz US images over the anterior aspect of the humeral head
(HH) demonstrate a rounded well-defined cortical erosion (arrowheads) filled with hypervascular synovial pannus (arrow)
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S. Bianchi and C. Martinoli
sion and synovial pannus and evaluate the extent of
such involvement, as well as to detect subtle bone
erosions that cannot be imaged on standard radiographs (Fig. 6.142b) (Speed and Hazleman 1999).
In a selected group of patients with symptomatic disease, US assessment of synovitis has demonstrated
subacromial subdeltoid bursitis as the most common
finding, occurring in up to 69% of cases, followed by
glenohumeral joint involvement in 58% and biceps
tendinitis in 57% (Alasaarela et al. 1998a). Overall, no correlation exists between these findings and
either the duration or stage of disease. A quantitative assessment of synovitis may be attempted by
measuring the widest distance between the humeral
head and the joint capsule in the axillary pouch and
posterior recesses (Alasaarela and Alasaarela
1994; Alasaarela et al. 1998a; Koski 1989, 1991).
Difficulties may arise with US when trying to distinguish effusion from the pannus in the posterior
recess, because graded compression with the probe
is not always able to squeeze the fluid away from this
site. In addition, when pressure is applied over the
pannus, this can be mobilized similarly to joint fluid.
Doppler systems may be helpful to assess the activity
of the inflammatory process by showing hyperemic
blood flow within the synovial tissue (Alasaarela
and Alasaarela 1994). In the biceps tendon sheath,
hyperemic flow is detected to a greater extent in
rheumatoid arthritis rather than in patients with
degenerative disease (Strunk et al. 2003). The reliability of these findings seems, however, too limited
for an objective assessment, particularly when Doppler imaging is used as an indicator of the response
to therapy. It is possible that US contrast agent will
have a role in this field (Wamser et al. 2003). Loss
of definition and thinning of the articular cartilage
can be demonstrated in advanced disease as well.
As regards the bony surfaces, US is able to reveal
erosions as well-defined cortical defects filled by
hypoechoic pannus: they may be isolated, confluent or generalized (Fig. 6.142c,d) (Alasaarela et
al. 1998b; Gibbon and Wakefield 1999; Hermann
et al. 2003). As mentioned earlier, US is useful when
obtaining a sample of fluid or synovium because it
can identify the ideal puncture site (where the fluid
accumulates more or the pannus is thicker) and can
provide easy guidance for directing the needle. The
intra-articular injection of corticosteroids or the
lidocaine test can be performed under US guidance,
thereby avoiding the risks of inadvertent intratendinous steroid injection or para-articular injections of
anesthetic. In these circumstances, the procedure of
needle placement is more accurate and less painful
under US guidance than when performed blindly.
The structures involved by the inflammatory process in polymyalgia rheumatica have also been investigated using US (Lange et al. 1998; Koski 1992;
Cantini et al. 2001). Most studies report a frequency
of bursitis (14–16%) lower than that of glenohumeral
joint synovitis (57–66%) in this disease (Lange et al.
1998; Koski 1992).
6.5.4.7
Shoulder Arthroplasty
Glenohumeral joint arthroplasty has become the
procedure of choice to treat patients with pain and
articular damage who do not respond to conservative
therapy. Regardless of the underlying disease (e.g.,
osteoarthritis, rheumatoid arthritis, rotator cuff
arthropathy, avascular necrosis, proximal humeral
fractures), the procedure is performed to relieve pain
and improve the range of shoulder motion. The prosthesis is composed of a metallic stem with a modular
humeral head that articulates either with the native
glenoid (shoulder hemiarthroplasty) or with a polyethylene or metal glenoid component (total shoulder arthroplasty) (Taljanovic et al. 2003). Reverse
shoulder prostheses are also obtained by reversing
the position of the ball (implanted on the glenoid)
and the socket (implanted on the humeral head).
Many types of device are available. Criteria for selection of a given type depend on the patient’s condition, the surgeon’s preference and the surgeon’s experience, and are beyond the scope of this chapter. The
main complications with shoulder arthroplasty are
loosening, superior migration, subluxation or dislocation of the humeral head and postoperative rotator
cuff tear. After shoulder arthroplasty, MR imaging
is of limited value owing to the artifact created by
the metallic implant. US has proved able to provide
information about the para-articular soft tissues
and the rotator cuff after shoulder arthroplasty,
especially in cases of poor postoperative outcome
and absence of radiographic signs of loosening and
migration (Westhoff et al. 2002; Sofka and Adler
2003). In this setting, the metallic hardware of the
humeral component of the prosthesis is readily demonstrated, enabling one to recognize the following
landmarks arranged in series: acromion, humeral
component, greater tuberosity (Sofka and Adler
2003). The prosthesis itself does not hinder examination of the rotator cuff. Its metallic component
appears as a linear echogenic interface with moderate posterior reverberation artifact. The examiner
Shoulder
should remember that moderate to severe regional
muscle atrophy – often involving the deltoid and the
teres minor – is frequently encountered in patients
who have undergone shoulder replacement and that
the subscapularis tendon (but not the supraspinatus) has often been taken off the lesser tuberosity
to allow surgical access (deltopectoral approach).
After placement of the prosthesis, the subscapularis
tendon is usually reinserted more medially, at the
site of humeral head resection rather than at the
anatomic insertion site: however, this tendon may
retear leading to an anteriorly unstable shoulder. In
general, preservation of the rotator cuff tendons in
these patients correlates with a good clinical outcome. In patients with loosening of the cup, dynamic
examination can depict some degree of instability of
the metallic hardware relative to the bony humerus
(Fig. 6.143).
6.5.4.8
Septic Arthritis and Bursitis
Septic arthritis of the glenohumeral joint has predilection for very young infants or elderly patients
with chronic debilitating disorders, such as diabetes,
cirrhosis and alcoholism. The intra-articular injection of corticosteroids greatly increases the likelihood of infectious disease because of steroid-induced
*
GT
a
b
reduction in the host defences. In addition, septic
arthritis may derive from accidental introduction of
bacteria during nonsterile arthrocentesis procedures.
Although US is a sensitive means for detection of
even small glenohumeral joint effusions, US imaging
findings usually do not allow the conclusive differentiation of a noninfected joint effusion from septic
arthritis (Cardinal et al. 2001). Definitive diagnosis requires analysis of the fluid, possibly aspirated
under US guidance, and must be performed in every
patient in whom the likelihood of infection is present.
As described in Chapter 18, large-bore (16–18 gauge)
needles are ideal for this purpose, because purulent
material can be too thick and viscous to be aspirated
with a small needle. Although the most adequate
puncture site may vary among patients, the posterior
approach is usually prefered. Using this access, the
needle should be inserted at mid-glenohumeral level
and directed into the posterior recess through the
infraspinatus. Septic arthritis is usually not associated with bursal infection unless a full-thickness tear
of the rotator cuff is present and allows free communication between these two spaces. Nevertheless, the
two entities may overlap and clinical differentiation
may be difficult. At US examination, an infected subacromial subdeltoid bursa may appear distended by
a complex effusion containing debris and septations
(Fig. 6.144a) (Cardinal et al. 2001; Lombardi et al.
1992; Rutten et al. 1998). The bursal walls may be
*
Acr
Acr
GT
c
Fig. 6.143a–c. Shoulder arthroplasty. a Schematic drawing illustrates a conventional humeral stem for shoulder arthroplasty. b,c
Oblique coronal 12–5 MHz US images obtained immediately lateral to the acromion (Acr) while keeping the arm b abducted
and c in neutral position. A series of bright echogenic surfaces reflecting native bone and metallic wares are observed. From
medial to lateral, they are: the polyethylene glenoid component (arrow) of the prosthesis, the cup of the humeral component
(arrowhead) and the greater tuberosity (GT). There is mild reverberation artifact underneath the prosthesis materials, absence
of the supraspinatus tendon and atrophy of the deltoid muscle (asterisks). Dynamic examination reveals some instability of
the metallic hardware relative to the bony humerus with increased distance (double arrow) between the humeral ware and the
greater tuberosity in neutral position
303
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S. Bianchi and C. Martinoli
thickened and peribursal hypoechoic strands reflecting edema in the surrounding soft tissues may be
associated findings (Fig. 6.144b). Although color and
power Doppler imaging may show hyperemic flow
in the synovial walls and around the bursa, this is
not regarded as a specific sign of infectious disease.
When the joint recesses are free of fluid, US is a
reliable means to obtain a correct diagnosis of isolated bursal involvement, thus avoiding arthrocentesis procedures with their potential complications
(Lombardi et al. 1992). During aspiration of the
infected bursa, US guidance may avoid inadvertent
contamination of the underlying sterile joint by traversing the infected bursa with the needle. In sepsis
of the acromioclavicular joint (Blankstein et al.
1985), US is a useful modality to exclude the involvement of the adjacent subacromial subdeltoid bursa
and glenohumeral joint. Main US findings include
superior bulging of the joint capsule, widening of the
joint space with erosions of the bony edges and debris
moving freely within the joint space (Widman et al.
2001). Although aspiration of the infected joint can
be performed blindly, US allows this procedure to be
carried out more confidently.
6.5.4.9
Acromioclavicular Joint Trauma and Instability
Subluxation or dislocation of the acromioclavicular joint may be a source of shoulder pain which
SupraS
*
HH
is often mistaken for a post-traumatic rotator cuff
lesion because of the close proximity of this joint
with the rotator cuff tendons. US is more sensitive
than standard radiographs in detecting low-grade
sprains of the acromioclavicular joint. These lesions
appear as widening of the joint cavity, distended by
hematoma or effusion, and bulging of the superior
capsule and ligament (Fig. 6.145). When the acromioclavicular joint is more severely injured with rupture of the coracoclavicular ligaments, an upward
displacement of the distal end of the clavicle can be
appreciated (Fig. 6.146). Although direct imaging of
the coracoclavicular ligaments is not feasible with
US because of the overlying clavicle, a hematoma in
the soft tissues between the clavicle and the coracoid may be regarded as an indirect sign of injured
ligaments. In addition, measurement of the coracoclavicular distance using anterior sagittal scans
may increase confidence in the diagnosis (Sluming,
1995). In severe dislocations with gross displacement of the clavicle, disruption of the muscular
insertion of the deltoid and/or the trapezius with a
hematoma developing anteriorly (deltoid lesion) or
posteriorly (trapezius lesion) to the cranial edge of
the clavicle can also be demonstrated (Heers and
Hedtmann 2005). Short-axis planes over the distal
clavicle are useful to evaluate the common fascia of
both muscles in order to avoid injuries being missed
(Heers and Hedtmann 2005). These structures are
important stabilizers of the acromioclavicular joint.
Although US is not routinely used as the screen-
*
HH
a
b
Fig. 6.144a,b. Septic bursitis. Two different cases. a Transverse 12–5 MHz US image over the short axis of the supraspinatus
tendon (SupraS) shows irregular lining of the bursa with focal hypoechoic thickening of the synovium (asterisks). Aspiration
revealed Staphylococcus aureus infection of the subacromial subdeltoid bursa. b Oblique sagittal 12–5 MHz US image obtained
immediately lateral to the acromion in a diabetic patient with massive rotator cuff tear and recent onset of shoulder swelling,
pain and fever demonstrates a heterogeneous bursal effusion containing material of mixed echogenicity (straight arrows).
Small hyperechoic foci (curved arrows) within the synovial cavity suggest purulent material. Note the hypoechoic changes (arrowheads) in the soft-tissue layers surrounding the bursa reflecting peribursal reactive inflammation and edema. Aspiration
revealed Streptococcus infection. HH, humeral head
Shoulder
1
Cl
23
Acr
Acr
Cl
Co
a
c
Cl
Acr
Co
b
d
Fig. 6.145a–d. Mild acromioclavicular joint sprain (type II injury). a Schematic drawing over the coracoacromial arch illustrates
the normal relationships of the acromioclavicular joint (1) with the coracoacromial ligament (arrow) and the trapezoid (2) and
conoid (3) components of the coracoclavicular ligament. Acr, acromion; Co, coracoid; Cl, clavicle. b Schematic drawing shows
the alterations observed in a mild sprain of the acromioclavicular joint. The joint space is widened (curved arrow) without
injury of the coracoclavicular ligament. c Coronal and d sagittal 12–5 MHz US images over the acromioclavicular joint in a
patient with post-traumatic shoulder pain reveal a widened joint space (arrowheads) and hypoechoic fluid (arrows) distending
the joint cavity. Acr, acromion; Cl, clavicle
Cl
Cl
Acr
Cl
Acr
Acr
Co
a
c
d
Cl
Acr
b
Acr
e
Acr
Cl
Cl
f
Fig. 6.146a–f. Acromioclavicular joint separation (type III injury). a Schematic drawing over the coracoacromial arch with b radiographic correlation demonstrates elevation (straight arrow) of the clavicle (Cl) relative to the acromion (Acr) with increased
acromioclavicular joint and coracoclavicular distances (curved arrows) indicating rupture of the ligaments. Co, coracoid. c,d
Coronal 12–5 MHz US images over the right acromioclavicular joint in a patient with post-traumatic joint dislocation. Note
the upward displacement (arrow) of the distal end of the clavicle (Cl) relative to the acromion (Acr). The double-headed arrow
between the dashed lines indicates measurement of the acromioclavicular joint width (c,e) and the superior displacement of
the clavicle (d,f). e,f Coronal 12–5 MHz US images of the normal left acromioclavicular joint for comparison
305
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S. Bianchi and C. Martinoli
ing modality for acromioclavicular joint separation,
some attempts have been made to correlate US findings in acute and chronic unstable acromioclavicular joints of varying severity with the radiographic
scale described by Tossy (Tossy et al. 1963) and the
Rockwood (Rockwood 1984) classification. At US,
the width of the joint is measured using a coronal
approach and compared with the contralateral side.
Theoretically, measurements are best obtained with
the patient’s arms hanging down and holding a 10 kg
weight in each hand to increase stress on the capsuloligamentous structures and allow identification of
subtle changes. Since variants can exist in the joint
width among normal subjects, the measure must be
related to the normal uninjured side. An index is
then calculated by dividing the acromioclavicular
joint width on the affected side by that on the normal
side. In normal subjects, the acromioclavicular joint
width should be no wider than 6 mm and the acromioclavicular index 1.0; patients with Tossy II instability have a mean acromioclavicular joint width of 10.2
mm on the injured side and an acromioclavicular
index of 0.5; patients with Tossy III instability and
indication for surgery have a mean acromioclavicular joint width of 22.3 mm on the injured side and
an acromioclavicular index of less than 0.25 (Kock
et al. 1996). As defined by Rockwood (Rockwood
1984), Tossy III type injury can be further subdivided depending on posterior displacement of the
clavicle (type IV), marked increase in the coracoclavicular distance by 2 or 3 times and the scapula
displaced inferiorly (type V) and dislocation of the
*
clavicle inferior to the acromion or the coracoid
(type VI). Although coracoid process fractures may
be secondary to anterior shoulder dislocation, they
most frequently occur in association with type III
acromioclavicular joint dislocations (Ogawa et al.
1997). The mechanism of these rare fractures seems
related to the occurrence of direct trauma to the
shoulder girdle and sudden strong pull of the short
head of the biceps and the coracobrachialis inserting at the coracoid process, leading to an avulsion
(Fig. 6.147). In most cases, conservative treatment is
appropriate. In the case of large avulsed fragments
or persistent pain, open reduction is advised with
coracoid screw and acromioclavicular fixation.
Post-traumatic osteolysis of the clavicle is a selflimiting disorder with gradual reparative changes
over a period of 4–6 months that may occur several
weeks up to several years after acromioclavicular
trauma (Dardani et al. 2000). The key to diagnosis
is the fact that changes occur only at the clavicular
end while the acromion remains normal. Although
the diagnosis is usually based on the patient’s history and radiographic findings, US is able to detect
the same abnormalities seen on plain films. At US,
the clavicular tip exhibits irregular cortical erosions
associated with joint space widening, joint effusion
and soft-tissue swelling, whereas the acromion
remains intact (Fig. 6.148). Post-traumatic osteolysis of the clavicle should be considered in the differential diagnosis when a patient experiences chronic
pain or soft-tissue swelling beyond the acute phase
of the injury. Care must be taken not to confuse this
Co
*
Co
a
b
Fig. 6.147a,b. Coracoid fracture. a Sagittal split-screen 12–5 MHz US image over the coracoid (co) with b oblique sagittal CT
reconstructed imaging correlation in a patient presenting with direct trauma to the shoulder girdle and acromioclavicular
joint separation (type III injury) reveals detachment and caudal displacement of the coracoid tip (white arrows) resulting from
traction by the short head of the biceps and the coracobrachialis (open arrows). Observe the nidus (arrowheads) of avulsion in
the coracoid and the associated hematoma (asterisk)
Shoulder
Acr
Acr
a
b
Fig. 6.148a,b. Post-traumatic osteolysis of the clavicle. a Coronal 10–5 MHz US image with b radiographic correlation in a patient
with painful tenderness over the acromioclavicular joint 6 months after a trauma demonstrates an irregular erosion (arrows)
of the distal end of the clavicle. Acr, acromion. (Courtesy of Dr. Nicolò Prato, Italy)
condition with shortening of the clavicle secondary
to resection of the distal end of clavicle, which can be
performed to treat acromioclavicular osteoarthritis
with secondary impingement, rheumatoid arthritis, ankylosing spondylitis and infection. Both the
patient’s history and local inspection allow a reliable
differentiation between these conditions.
6.5.4.10
Sternoclavicular and Costosternal Joint Pathology
Injuries to the sternoclavicular joint are uncommon
given the strong ligamentous support of this joint.
Traumatic sternoclavicular instability, including
subluxation and dislocation, is always secondary to
a well-defined traumatic event. In these patients,
disability has a longer duration in cases of posterior dislocation than anterior dislocation, presumably because of coexistent injury to the mediastinal soft tissues posterior to the sternum. US has
proved able to identify posterior sternoclavicular
dislocation as well as to evaluate its reduction in
the operating room (Benson et al. 1991; Pollock
et al. 1996). In addition to traumatic injuries, other
atraumatic conditions affecting the sternoclavicular
joint are amenable to US examination, including
degenerative osteoarthritis (Hiramuro-Shoji et
al. 2003). Similar to that observed in the acromioclavicular joint, degenerative osteoarthritis of the
sternoclavicular joint is characterized by narrowing
of the joint space, osteophytes and para-articular
cysts (Fig. 6.149a,b). This condition usually affects
the dominant arm of women between the ages of
40 and 60 years. Previous neck surgery with spinal
accessory nerve lesion is also claimed as a predis-
posing factor, as it causes downward and forward
drop of the shoulder leading to additional stress
on the sternoclavicular joint (Hiramuro-Shoji et
al. 2003). In rheumatoid arthritis, sternoclavicular
joint involvement shows irregularities of the osseous
surfaces with osteolysis of the medial end of the
clavicle and synovial inflammation (Fig. 6.149c,d).
Tietze’s syndrome, which is also referred to as costosternal syndrome or anterior chest wall syndrome,
is a benign, self-limiting condition characterized by
swelling of the costal cartilages and gradual onset of
pain in the anterior chest wall exacerbated by coughing and sneezing. US is able to reveal an increased
volume of the costal cartilages with irregular calcifications and perichondral soft-tissue swelling in
clinically and radiographically apparently normal
costochondral joints of patients with anterior chest
pain (Choi et al. 1995; Kamel and Kotob 1997). In
these patients, US has been proposed as a means to
guide local steroid injection for treatment (Kamel
and Kotob 1997).
6.5.4.11
Quadrilateral Space Syndrome
In neuropathies around the shoulder, the small size
of nerves, the complex regional anatomy and problems of access due to the acoustic shadowing from
superficial bone structures, makes direct evaluation
of nerves difficult with US. Axillary neuropathy may
be caused by stretching injuries (anterior dislocation) or extrinsic compression in the quadrilateral
space caused by fractures of the upper humerus,
improper use of crutches, casts, fibrous bands and
inferior (from the 9 to 7o’clock positions) paragle-
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S. Bianchi and C. Martinoli
Cl
St
St
Cl
a
b
Cl
Cl
St
c
St
d
Fig. 6.149a–d. Sternoclavicular joint abnormalities. a,b Degenerative osteoarthritis. a Transverse 12–5 MHz US image over the
right stenoclavicular joint shows irregularities and osteophytes (arrowheads) of the articular surface of the clavicle (Cl) and
sternum (St). b Normal contralateral joint for comparison. c,d Rheumatoid arthritis. c Transverse color Doppler 12–5 MHz US
image over the right stenoclavicular joint with d coronal contrast-enhanced T1-weighted MR imaging correlation shows joint
space widening, irregularities in the medial end of the clavicle (arrow) reflecting osseous erosions and synovial hyperemia
(arrowheads) as seen at Doppler imaging and after gadolinium uptake
noid cysts (Linker et al. 1993; Chautems et al. 2000;
Tung et al. 2000). Static (fibrous bands, occlusion of
the posterior circumflex artery, muscle hypertrophy) and dynamic (nerve stretching in some arm
positions, such as occur in throwing athletes at the
extremes of joint motion) traction and compression on the axillary nerve seem play a role in this
syndrome (Perlmutter 1999). Iatrogenic damage
during arthroscopic procedures around the coracoid or by posterior surgical arthroscopic portals
has also been reported outside the quadrilateral
space (Lo et al. 2004). When the entrapment of the
axillary nerve occurs in the quadrilateral space,
there is selective denervation of the teres minor
muscle because the anterior branch of the nerve
(supplying the deltoid) is spared. Clinically, axillary
neuropathy is often found as an occasional finding
during an examination of the shoulder for other
symptomatic abnormalities. This would suggest that
the disease may exist in an asymptomatic or subclinical entity (Sofka et al. 2004b; Cothran and
Helms 2005). When symptomatic, it is associated
with vague, often nonspecific, posterior shoulder
pain, paresthesias over the external aspect of the
shoulder and weakness exacerbated by abduction
and external rotation of the arm. Because the teres
minor is the only muscle involved, this condition
can be difficult to recognize on the basis of clinical
grounds alone, because the action of the teres minor
cannot be clearly separated from the contribute of
the infraspinatus. Even without any detectable softtissue abnormality along the course of the nerve,
the diagnosis of axillary neuropathy is based on the
evidence of volume loss and hyperechoic changes of
the involved muscles in the absence of a tendon tear
(Martinoli et al. 2003). These signs are particularly
suggestive given that teres minor tendon disruptions
are extremely rare, even in cases with massive rotator cuff tears. At US, the atrophy of the teres minor
is best assessed by comparing the appearance of
this muscle with that of the adjacent infraspinatus
on sagittal scans (Fig. 6.150). On the other hand,
atrophy of the deltoid can be revealed by a reduced
thickness of this muscle relative to the contralateral
309
Shoulder
Del
SSp
InfraS
a
b
*
*
c
d
Fig. 6.150a–d. Axillary neuropathy with selective denervation of the teres minor muscle. a Sagittal extended field-of-view 12–5 MHz
US image obtained over the right posterior fossa demonstrates loss in bulk and increased echogenicity of the teres minor muscle
(arrowheads), a finding that is consistent with fatty atrophy, whereas the infraspinatus muscle (arrows) is preserved. SSp, spine
of the scapula; Del, deltoid muscle. b Oblique coronal T1-weighted MR imaging correlation confirms chronic denervation in the
form of fatty infiltration of the teres minor (arrowheads) related to axillary neuropathy. Note the normal infraspinatus muscle
(InfraS) and some hypointense structures (curved arrow) crossing the quadrilateral space, consistent with the axillary nerve
and the posterior circumflex artery. c,d Long-axis 12–5 MHz US images over c the right (arrowheads) and d the left (arrows)
teres minor muscles demonstrate striking echotextural differences, with the right belly being reduced in bulk and much more
echogenic than the left. On both sides, tendons are intact (asterisk)
one on coronal scans (Fig. 6.151). In addition, US is
able to demonstrate any possible space-occupying
lesion in the quadrilateral space, such as paralabral
cysts extending off the inferior aspect of the glenoid
in association with a tear of the inferior labrum
(Sanders and Tirman 1999; Robinson et al. 2000).
The main differential diagnosis of quadrilateral
space syndrome is the Parsonage-Turner syndrome,
in which the involvement of muscles usually relates
to more than one nerve distribution.
6.5.4.12
Suprascapular Nerve Syndrome
Suprascapular neuropathy is an unusual syndrome
leading to chronic shoulder pain and weakness
(Fehrman et al. 1995). This condition may be secondary to a constriction of the suprascapular nerve
at the suprascapular notch or at the spinoglenoid
notch as a result of a variety of condition, including
stretching injuries, ligament abnormalities, overuse
or space-occupying lesions. From the pathophysiologic point of view, if the suprascapular nerve is
entrapped at the supraspinous notch, both supraspinatus and infraspinatus muscles undergo denervation changes; if it is compressed at the spinoglenoid
notch, denervation is limited to the infraspinatus
muscle whereas the supraspinatus is spared. Because
the suprascapular nerve is a purely motor nerve,
there is no sensory loss. Paralabral cysts are the leading cause of suprascapular neuropathy (Takagishi
et al. 1991; Bousquet et al. 1996; Bredella et al.
1999; Tung et al. 2000; Weiss and Imhoff 2000;
Ludig et al. 2001; O’Connor et al. 2003). Two possible theories have been hypothesized to explain the
origin of these cysts. The first assumes that they
are secondary to tears of the glenoid labrum allowing the joint fluid to extrude into the periarticular
tissues; the second suggests that they would arise
310
S. Bianchi and C. Martinoli
a
c
d
Acr
GT
b
e
Acr
Acr
GT
Fig. 6.151a–e. Axillary nerve injury with deltoid denervation due to damaging of the anterior branch of the axillary nerve in a
patient who had undergone previous shoulder dislocation and humeral fracture in a traffic accident. a Long-axis 12–5 MHz US
image over the intact supraspinatus tendon shows marked atrophy of the deltoid muscle (arrows). b Corresponding contralateral normal side showing the normal deltoid (arrows). Acr, acromion; GT, greater tuberosity. c Oblique-coronal T1-weighted
and d fat-suppressed T2-weighted MR images confirm marked thinning of the deltoid muscle (arrows), which exhibits slightly
increased T2 signal related to the denervation process. e Photograph of the right shoulder shows prominence of the acromion
(Acr) and the coracoid (arrowhead) on the skin due to the atrophy of the deltoid muscle
from areas of myxoid degeneration of para-articular structures following labral tears, a pathogenesis
somewhat similar to that of other ganglion cysts.
In the shoulder, paralabral cysts are usually associated with tears of the superior and posterior glenoid labrum (from the 8 to 11 o’clock positions),
as a result of a SLAP lesion or posterior instability,
respectively. Only rarely they extend off the anterior
and inferior aspect of the glenoid. Once developed,
paralabral cysts can show a progressive enlargement
due to a one-way valve mechanism leading to the
passage of the joint fluid into the cyst through a thin
pedicle (Fig. 6.152a,b). During their expansion, they
spread into the spinoglenoid notch, the suprascapular notch, or both notches of the scapula lying deep
to the myotendinous junction of either the supraspinatus or the infraspinatus, and may or may not
cause nerve entrapment and muscle denervation
(Fig. 6.152c) (Tung et al. 2000). US can easily recognize secondary changes of nerve damage, including
loss in bulk and increased reflectivity of the innervated muscles due to edema and fatty replacement
(Figs. 6.153, 6.154). A correlation was found between
the size of paralabral cysts and the onset of denervation symptoms, significantly more muscle denervation occurring with larger cysts (volume 6.0 cm3;
diameter 3.1 cm) compared with all other paralabral
cysts (volume 2.2 cm3) (Tung et al. 2000). A careful scanning technique is recommended for imaging the posterior shoulder, starting with near-field
settings to examine the rotator cuff tendons and
then adjusting both the focal zone and image magnification to the far-field in order to explore the
scapular notches (Martinoli et al. 2003). In fact,
even large cysts could be easily missed while performing a standard US examination of the shoulder
due to their deep location, far from the rotator cuff
tendons. In many cases, spinoglenoid cysts develop
in the most cranial portion of the notch, in close
proximity to the scapular spine. Placing the hand
on the opposite shoulder during scanning may be
helpful to decrease the depth of the posterior fossa
and to make this area more readily examined with
US. US demonstrates paralabral cysts as rounded or
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S. Bianchi and C. Martinoli
Del
InfraS
SSp
a
SSp
b
*
*
c
d
Fig. 6.154a–d. Suprascapular neuropathy: spinoglenoid notch entrapment. a Sagittal extended field-of-view 12–5 MHz US image obtained over the right posterior fossa demonstrates loss in bulk and increased echogenicity of the infraspinatus muscle
(InfraS), whereas the teres minor (arrows) retains a normal echotexture. SSp, spine of the scapula. Del, deltoid muscle. b Sagittal
12–5 MHz US image obtained over the spinoglenoid notch with c transverse and d oblique coronal MR imaging correlation using
STIR sequences reveals a cystic lesion (asterisk) located inferior to the spine of the scapula (SSp) and deep to the infraspinatus
muscle (arrows), consistent with a ganglion cyst. Note the diffuse high signal intensity of the infraspinatus muscle related to
denervation edema and the preserved teres minor (arrowheads)
oval hypoechoic lesions with well-defined margins,
relatively fixed in location and shape during active
and passive shoulder movements (Hashimoto et
al. 1994; Bouffard et al. 2000; Martinoli et al.
2003). The continuity of the cyst with a defect in
the posterior labrum can be revealed with US. A
mass effect on the adjacent tendon and muscle is
often demonstrated as well. Then, a careful evaluation of rotator cuff tendons should be carried out
to exclude a possible tendon rupture as the cause of
the muscle atrophy. The main differential diagnosis of paralabral cysts includes varicosities in the
spinoglenoid notch (Carroll et al. 2003). Although
enlarged spinoglenoid notch veins appear as hypoechoic round or oval images mimicking a cyst, they
are not stationary and change shape and size during
shoulder movements (an increased venous size is
typically appreciated while the arm is in external
rotation, whereas these vessels tend to collapse in
internal rotation) (Fig. 6.155). On the other hand,
Doppler imaging does not demonstrate flow signals
within these veins because the flow velocities are
too low. In recent papers, the association of vascular abnormalities in the spinoglenoid notch area
with suprascapular neuropathy has been described
(Bredella et al. 1999; Ludig et al. 2001; Carroll et
al. 2003). In these cases, it is not still clear whether
the dilated venous plexus and the compressed nerve
are a separate expression of a narrow suprascapular
tunnel or whether the varicosities themselves may
lead to nerve impingement. In cases of suprascapular
neuropathy caused by paralabral cysts, percutaneous needle aspiration of the cyst can be attempted
under US guidance (Hashimoto et al. 1994; Chiou
et al. 1999). As described in Chapter 18, the procedure has three main goals: to confirm the diagnosis
by showing a viscous mucoid content; to drain the
fluid as much as possible to reduce the internal pres-
Shoulder
*
*
SA
a
b
c
Fig. 6.157a–c. Brachial plexus trauma in a young patient following a motorcycle accident. a Long-axis 12–5 MHz US image
obtained over the upper trunk nerves at the interscalene area shows a transected nerve (C7). Note the hypoechoic swollen
appearance of the proximal and distal stumps (arrowheads), each of which ends in a terminal neuroma (asterisk). b Long-axis
12–5 MHz US image over the divisions and cords (open arrows) of the plexus at the supraclavicular area demonstrates ill-defined fusiform hypoechoic swelling (arrowheads) of three nerves bundles, superficial to the subclavian artery (SA). c Coronal
T2-weighted MR imaging correlation demonstrates an increased signal (arrow) in the soft tissues of the interscalene area
*
*
SA
a
b
SA
c
d
e
Fig. 6.158a–e. Recent brachial plexus trauma in a patient who underwent a bicycle accident 15 days previously. a–c Series of
short-axis 12–5 MHz US images obtained from a proximal to c distal over brachial plexus nerves (open arrows) demonstrate
progressive swelling of some fascicles (arrowheads) as they course superficial to the subclavian artery (SA). In c, the abnormal
fascicles are encased in a hypoechoic and irregular mass (arrowheads) reflecting a traumatic neuroma. Asterisks, scalene muscles. d Oblique sagittal T1-weighted and e fat-suppressed T2-weighted MR images demonstrate the neuroma as a well-defined
mass (arrowheads) encasing the cords of the plexus. Due to its recent formation, the neuroma is hyperintense on T2-weighted
sequences
Overall, we believe US is more accurate than MR
imaging for establishing the level of involvement,
namely whether the upper or the lower plexus are
injured, in patients with postganglionic injuries. On
the other hand, MR imaging is more sensitive for
detecting pseudomeningoceles and lesions occurring in the inner spine. In clinical practice, we suggest a combined approach with MR imaging and US
to evaluate the traumatized patient, the first technique to evaluate the spine and the foramina, the
second to assess the nerves outside the spine. Detection of nerve abnormalities with US may have clinical implications. It may provide an early assessment
of the status of the plexus in the immediate phases
after the trauma, when clinical findings are not
yet conclusive as to whether or not brachial plexus
damage requires intervention. In general, patients
with total plexopathy have the largest neuromas,
as these probably reflect the sum of more than one
lesion. On the other hand, patients with small neuromas are usually managed conservatively and show
the best functional recovery without surgery.
6.5.5.2
Neoplastic Involvement of the Brachial Plexus
Imaging of brachial plexus tumors should consider two main classes of disorder: metastatic
disease and radiation plexopathy, and neurogenic
315
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primary tumors. Although many histotypes have
been reported to metastasize to the brachial plexus,
including breast cancer, bronchogenic carcinoma,
lymphoma and squamous cell carcinoma of the head
and neck, the nerve involvement in patients with
breast cancer is far more common – accounting for
approximately 24% of all nontraumatic brachial
plexopathies – because one of the major lymphatic
drainage routes of the breast is through the apex of
the axilla (Wittenberg and Adkins 2000). In some
patients, the metastatic tumor appears as a welldefined solid mass usually located in the soft tissues
of either the suprascapular or the infraclavicular
area (pattern I). It may exhibit irregular margins and
a hypoechoic echotexture and can be seen encasing
the nerves with an abrupt nerve-to-tumor interface
(Fig. 6.159a,b) (Graif et al. 2004). Most often, the
neoplasm invades the brachial plexus leading to a
segmental thickening and hypoechoic appearance
of the involved nerves without causing a clear mass
*
T
effect (pattern II). The infiltrative spreading of the
tumor causes an abnormal fusiform thickening of
the nerve (Fig. 6.159c–e). Satellite lymph nodes are
often associated. Color Doppler imaging can depict
intratumoral vessels and may help in depicting displacement and infiltration of the subclavian vessels
and distinguishing the infiltrated cords from the
adjacent blood vessels. Compared with MR imaging, US seems better able to delineate the tumor
tissue and the nerve involvement in the interscalenic and supraclavicular area owing to its higher
spatial resolution capabilities. On the other hand,
MR imaging has the advantage of a panoramic view
with the possibility of delineating both vertebral and
pleural involvement. In patients who have received
radiation therapy to the axillary region, radiationinduced damage to the brachial plexus nerves is a
common cause of brachial plexopathy, accounting
for approximately 30% of the cases of nontraumatic
plexopathies (Wittenberg and Adkins 2000). The
*
*
*
a
b
SA
Rib
c
d
e
Fig. 6.159a–e. Metastasis of breast carcinoma with brachial plexus involvement. Two different cases. a Long-axis 12–5 MHz US
image over the divisions and cords of the plexus in the supraclavicular region with b coronal T1-weighted MR imaging correlation shows two individual nerve branches (open and white arrowheads) abruptly encased by a large hypoechoic solid mass
(T) with spiculated margins and infiltrative spreading (asterisks) in the surrounding soft tissues. MR image demonstrates that
the mass (asterisk) arises from the first rib and is associated with apical subpleural involvement. c Long-axis and d short-axis
12–5 MHz US images over the divisions and cords of the plexus with e correlative transverse T2-weighted MR image show
an abnormal hypoechoic thickening of the involved nerves (arrows) over the interscalene and supraclavicular area, reflecting
an infiltrative spreading of the tumor. The individual nerves have undefined margins and tend to coalesce in a thick cord-like
structure coursing alongside the subclavian artery (SA). MR imaging demonstrates the cranial extension (arrows) of the metastatic tumor in the paravertebral area
Shoulder
distinction between recurrent or residual disease
and radiation-induced neuropathy can be difficult
both clinically and on imaging studies. Neurologic
damage after radiation therapy may be observed
several months to years after treatment. Common
symptoms of radiation neuropathy include upper
brachial plexus involvement, doses in excess of 60
Gy, a latency period of less than 1 year (peak at
10–20 months), absent pain and lymphedema in the
upper limb. On the other hand, neoplastic plexopathy seems more typically associated with symptoms
related to the lower plexus nerves, early and severe
pain, hand weakness, a dose of less than 60 Gy and a
period of latency after completion of radiation therapy of more than 1 year (Wittenberg and Adkins
2000). In radiation fibrosis, US demonstrates diffuse thickening of the nerve fascicles in the absence
of a focal mass. Unlike tumor infiltration (see for
comparison Fig. 6.159c,d), the nerve thickening is
more uniform and some faint fascicular pattern is
preserved (Fig. 6.160). However, this finding is far
from being specific to radiation fibrosis and the differentiation between radiation damage and residual
tumor or recurrence can be problematic as the two
conditions may coexist (Graif et al. 2004). Postirradiation plexus lesions should be operated on as early
as possible to stabilize the clinical course (as soon
as paresthesias appear and before the onset of pain).
US can provide a useful means to monitor changes
in the cross-sectional volume of the affected nerve
fascicles over time.
Neurogenic primary tumors of the brachial
plexus, including for the most neurofibromas and
schwannomas, are far less common than metastatic
disorders (Graif et al. 2004). The US characteristics of these tumors are the same as those already
described in other locations of the body. The feature of value in distinguishing them from other
soft-tissue masses – and especially from enlarged
supraclavicular lymph nodes – is demonstration of
the continuity between the tumor and the nerve of
origin (Fig. 6.161) (Shafighi et al. 2003).
6.5.5.3
Parsonage-Turner Syndrome
Parsonage-Turner Syndrome, which is also known
as “acute brachial plexus neuritis,” is a rare clinical
entity of unknown cause consisting of sudden severe
shoulder pain followed by the onset of profound
muscle weakness and flaccid paralysis of the shoulder girdle and upper arm. This disorder has a peak
rate of incidence between the third and fifth decades
and a slight male predominance. Although different
factors, including viral infection, trauma, surgery
and autoimmunity have been suspected to play a
causative role, the etiology of the disease remains
unknown. There is usually no loss of sensation associated with the weakness. Several patterns of weakness are reported, the involvement of the suprascapular nerve being the most common. The most
frequent pattern relates to the multiple involvement
of the axillary (deltoid and teres minor), suprascapular (supraspinatus and infraspinatus), long thoracic
(serratus anterior) and musculocutaneous (coracobrachialis, biceps brachii, brachialis) nerves. Regarding the nerve root involvement pattern, C5 and C6
SA
a
b
Fig. 6.160a,b. Radiation fibrosis. a Short-axis and b long-axis 12–5 MHz US images of the brachial plexus nerves (white arrows)
in the supraclavicular region obtained 1 year after radiation therapy for breast carcinoma in a patient with reversible brachial
plexopathy. There is mild homogeneous swelling of the nerve fascicles (arrowheads) which appear less defined. No focal mass
is observed. SA, subclavian artery
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S. Bianchi and C. Martinoli
SA
SA
1st
*
SA
rib
a
b
c
*
d
e
f
Fig. 6.161a–f. Schwannoma of the brachial plexus. a Series of short-axis 12–5 MHz US images obtained from a proximal to
c distal over brachial plexus nerves with d–f corresponding oblique sagittal T1-weighted MR images demonstrate a rounded
mass (asterisk) with smooth contour and solid hypoechoic echotexture in the mid-portion of the supraclavicular area. The mass
lies adjacent to the subclavian artery (SA) and is in proximal and distal continuity with one of the nerve cords (arrow). Note
the spared fascicles (arrowheads) as they pass alongside the tumor. The continuity between the mass and the nerve of origin
helps to rule out a supraclavicular lymph node
are the most commonly affected. The prognosis is
generally benign, with approximately 75% recovery
within 2 years, and treatment is symptomatic (analgesic drug and physical therapy). Electrodiagnostic
studies may indicate the complex pattern of muscle
involvement. Imaging studies may be helpful to rule
out any other local abnormalities, such as rotator
cuff tears, shoulder impingement syndrome and calcific tendinitis, thus preventing unnecessary surgery
in some patients owing to diagnosis failure (Helms
et al. 1998; Helms 2002). At US examination, the
affected muscles appear smaller in volume as a result
of atrophy and diffusely hyperechoic in relation to
denervation edema and fatty infiltration (Fig. 6.162).
Although US is able to confirm the clinical diagnosis,
MR imaging seems more reliable for depicting the
overall extent of muscle atrophy around the shoulder
(Bredella et al. 1999; Helms, 2002).
6.5.5.4
Thoracic Outlet Syndrome
Thoracic outlet syndrome is a range of disorders arising from the passage of the subclavian artery and
vein and brachial plexus nerves through the three
anatomic spaces of the thoracic outlet – the interscalene triangle, the costoclavicular space and the
retropectoralis minor space (subcoracoid tunnel)
– the narrowing of which can lead to arterial, venous
or nervous compression (Demondion et al. 2000).
Compression of these neurovascular structures with
related onset of symptoms may occur at rest or during
dynamic maneuvers, such as during holding the arm
overhead and backward (hyperabduction). Typical
symptoms include upper limb ischemia, pallor, coolness, fatigability, pain, muscle cramp and pulselessness. In the arterial thoracic outlet syndrome, color
Doppler imaging and waveform analysis must be
obtained from both subclavian and axillary arteries.
These techniques can demonstrate high peak systolic
velocities in the subclavian artery at the compression site and diminished or absent blood flow in the
axillary artery (or the distal arteries of the arm) with
hyperabduction maneuvers (Fig. 6.163) (Longley et
al. 1992). This latter sign actually seems to be more
reliable because the vessel stenosis most often occurs
at the level of the costoclavicular space as a result of
fibro-osseous or fibromuscular abnormalities and,
therefore, cannot be directly depicted with US due to
Shoulder
*
a
b
*
c
Fig. 6.162a–c. Parsonage-Turner syndrome in a patient with recent onset of intense weakness of the shoulder muscles. a Sagittal
12–5 MHz US image over the posterior fossa with b oblique sagittal T1-weighted MR imaging correlation demonstrates marked
hyperechoic echotexture of the infraspinatus (open arrow) and teres minor (white arrows) muscles. Note that the intramuscular
tendons (arrowheads) appear hypoechoic due to anisotropy. c Oblique coronal and transverse (in the insert) fat-suppressed T2weighted MR images reveal marked high signal intensity throughout the supraspinatus (asterisks) and the infraspinatus (star)
muscles. Due to a coexisting involvement of the teres minor, the overall denervation pattern is characteristic of a neurogenic
deficit of both suprascapular and axillary nerves
a
c
b
d
Fig. 6.163a–d. Arterial thoracic outlet syndrome. a,b Spectral Doppler waveform analysis obtained from the axillary artery while
keeping the arm a in a neutral position and b during hyperabduction test. In neutral position, the axillary artery shows normal
high-resistance pulsatile flow. During the stress maneuver, the normal arterial blood flow abruptly converts into a “tardus-parvus” poststenotic pattern, characterized by low-velocity systolic peaks (arrowheads). This abnormal pattern was transient and
returned to normal as soon as the patient assumed a neutral position again. c,d Photographs showing the positioning of the
patient and transducer, respectively
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Shoulder
6.5.6
Shoulder Masses
Depending on the age of presentation, up to 60% of
benign soft-tissue tumors arising around the shoulder are lipomas (Kransdorf 1995). US detection of
superficial lipomas arising in the subcutaneous tissue
(Fig. 6.165a,b), within the fat planes of the axilla or
deep in the anterior deltoid muscle (Fig. 6.165c,d) is
generally not a diagnostic problem. In contrast, deepseated lesions within or among shoulder muscles may
be difficult to recognize with US (Fig. 6.165e-g). In
these cases, contact of the mass with the surrounda
ing anatomic structures during certain movements
of the arm may lead to symptoms that can mimic a
true impingement syndrome. If arising in the region
of the neurovascular bundles, lipomas may also cause
nerve entrapment, resulting in weakness, pain and
numbness. Apart from lipomas, the other soft-tissue
tumors arise around the shoulder with a similar incidence as elsewhere in the body. A peculiar tumor-like
condition which has a predilection for the shoulder
area is elastofibroma dorsi, which is almost invariably
located in the inferior part of the thoracoscapular
space elevating the inferior angle of the scapula. It
merits a separate discussion.
b
c
d
Del
Del
Del
Del
e
f
g
S
1
InfraS
*
Scapula
*
2
S
*
3
4
InfraS
Scapula
Fig. 6.165a–g. Lipomas around the shoulder girdle: spectrum of US appearances. a,b Subcutaneous lipoma. a Photograph shows
a prominent soft-tissue mass (arrow) lying on the posterior aspect of the shoulder. b Extended field-of-view 12–5 MHz US image
demonstrates a superficial solid mass (arrows) within the subcutaneous tissue, characterized by thin and highly reflective linear
echoes oriented parallel to the skin and embedded in a hypoechoic background, consistent with a lipoma. c,d Intramuscular lipoma.
c Transverse 12–5 MHz US image with d T1-weighted MR imaging correlation demonstrates an ovoid compressible solid mass
(arrows) with well-defined outlines inside the deltoid muscle (Del). Note the typical echotexture and the homogeneous high T1
signal intensity of the mass. e–g Deep-seated intermuscular lipoma. e Sagittal 12–5 MHz US image over the right infraspinous
fossa with f oblique sagittal T1-weighted MR imaging correlation reveals a homogeneous hyperechoic lipoma (asterisk) causing
superficial displacement of the infraspinatus muscle (InfraS). S, spina of the scapula; 1, supraspinatus; 2, subscapularis; 3, infraspinatus; 4, teres minor. The patient complained of right shoulder pain exacerbated by internal rotation of the arm and underwent
US examination for a suspected impingement syndrome. g US appearance of the normal left posterior fossa for comparison
321
Shoulder
the superficial muscles, since the tumor echotexture
blends with that of skeletal muscle. Elastofibromas
have a peculiar texture composed of an inhomogeneous echogenic background with interspersed
linear or curvilinear hypoechoic strands, reflecting the histology of the tumor: these strands are
typically arrayed in series with oblique orientation
throughout the mass. One-to-one comparison with
the CT, MR imaging and gross pathology findings
revealed that the hypoechoic strands are compatible with areas of fat, whereas the echogenic background reflected the predominantly fibroelastic
bulk of the mass (Fig. 6.167) (Bianchi et al. 1997). It
is known that fat can assume a variable echogenicity
at US, including an anechoic appearance (pure fat)
or a hyperechoic appearance (fat interspersed with
other tissues). It has been clearly shown that pure
fat is anechoic, whereas fat interspersed with other
tissues tends to become hyperechoic (Fornage et
al. 1991). The fat within the stripes is relatively
homogeneous. Therefore we can expect it can be
hypoechoic. In contrast, the higher echogenicity of
the fibroelastic background of the mass could result
primarily from the amount of acoustic interfaces
caused by fibrous tissue against interspersed fat or
by intrinsic heterogeneity of the fibrous tissue itself,
reflecting varying proportions and distribution of
degenerated elastic fibers and collagen. Although
elastofibromas have been shown to have increased
a
fluorodeoxyglucose (FDG) metabolism at positron
emission tomography (PET) and PET-CT (Pierce
and Henderson 2004), color Doppler imaging
does not usually detect blood flow signals within
them (Bianchi et al. 1997). The main differential
diagnoses for parascapular masses are lipomas and
metastases (Fig. 6.168a–c). However, elastofibroma
has a typical US appearance which should allow it
to be distinguished from these lesions on the basis
of a well-defined multilayered pattern. Diagnostic
pitfalls might be encountered with US in cases of
parascapular hemangiomas. In fact, hemangiomas
may exhibit a complex ill-defined appearance
with prominent hyperechoic components reflecting fat and prominent hypoechoic vascular channels (Fig. 6.168d,e). The hypervascular appearance
of these masses at color Doppler imaging and the
detection of phleboliths (which occur in approximately 50% of cases) should help the differential
diagnosis. The distinction between elastofibromas
and extra-abdominal desmoids, which contain variable amounts of collagen and may also be found
around the shoulder, is essentially based on the
absence of well-defined striations at US. Overall, we
believe that, in the appropriate clinical setting, the
US-based diagnosis of elastofibroma can obviate
unnecessary patient anxiety and the need of further imaging and unnecessary surgical procedure
or biopsy.
b
Fig. 6.167a,b. Elastofibroma dorsi. a Transverse 12–5 MHz US image with b CT correlation reveal an ill-defined crescent-like
mass (large arrows) with the typical striated appearance made of alternating hypoechoic planes of fat (small arrows) and
fibroelastic tissue. The elastofibroma dorsi grows in the fat plane interposed between the extrinsic back muscles (arrowhead)
and the costal plane (curved arrow)
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Arm
7
Arm
Carlo Martinoli and Stefano Bianchi
CONTENTS
7.1
Introduction 333
7.2
7.2.1
7.2.2
7.2.3
Clinical and US Anatomy 333
Anterior Arm 333
Posterior Arm 336
Neurovascular Bundle 339
7.3
7.3.1
7.3.1.1
7.3.1.2
Arm Pathology 340
Anterior Arm 341
Bicipital Sulcus Pathology 341
Median Neuropathy Following Brachial
Artery Catheterization 341
7.3.1.3 Supracondylar Process Syndrome 342
7.3.2 Posterior Arm 344
7.3.2.1 Spiral Groove Syndrome 344
References
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347
7.1
Introduction
Pathology of muscles and tendons of the arm is not
very common and clinically relevant. On the other
hand, compressive neuropathies affecting the main
nerve trunks of the upper limb, and especially the
median nerve and the radial nerve, may present with
a spectrum of confusing and, sometimes, ambiguous clinical pictures for the physician. These neuropathies are often related to anatomic constraints,
may be acute or chronic, and require a thorough
understanding of the pathophysiology and clinical
correlation. Current improvements in US technology have contributed significantly to the more accurate diagnosis of these conditions.
C. Martinoli, MD
Associate Professor of Radiology, Cattedra “R” di Radiologia
– DICMI – Università di Genova, Largo Rosanna Benzi 8, 16132
Genova, Italy
S. Bianchi, MD
Privat-docent, Université de Genève, Consultant Radiologist,
Fondation et Clinique des Grangettes, 7, ch. des Grangettes,
1224 Genève, Switzerland
7.2
Clinical and US Anatomy
The arm extends from the shoulder to the elbow. It
is formed by two main compartments – anterior and
posterior – separated by a plane passing through the
humerus and the lateral and medial intermuscular
septa, which are thick fibrous extensions of the brachial fascia attached to the medial and lateral supracondylar ridge of the humerus (Fig. 7.1). The anterior
compartment (flexor compartment) contains three
muscles – the coracobrachialis, the biceps brachii and
the brachialis – and the musculocutaneous nerve.
The posterior compartment (extensor compartment)
houses the large triceps brachii muscle, consisting
of three heads – long, lateral and medial – and the
radial nerve. At the upper medial aspect of the arm,
the main neurovascular bundle, consisting of the brachial artery, some veins and three nerves – median,
ulnar and radial – courses in the neurovascular
compartment, a groove delimited by a division of
the medial intermuscular septum and bounded by
the biceps anteriorly and the triceps posteriorly. A
basic description of the normal and US anatomy of
the anterior and posterior compartments is included
here.
7.2.1
Anterior Arm
The anterior compartment of the arm houses three
muscles: the coracobrachialis, the biceps brachii
and the brachialis (Fig. 7.2). The coracobrachialis
takes its origin from the tip of the coracoid process, medial to the insertion of the short head of the
biceps, and continues down and laterally to insert
onto the medial aspect of the middle third of the
humeral shaft. The biceps brachii is formed by a
combination of two muscle bellies: the long head and
the short head. As already described in Chapter 6,
the long head originates from a long tendon which
Arm
the two heads of the biceps unite to create a large
muscle which is located superficial to the brachialis
and ends in a long distal tendon which attaches into
the radial tuberosity (see Chapter 8). The brachialis
muscle is located between the distal biceps brachii
and the humeral shaft (Fig. 7.2a). It originates from
the distal half of the anterior face of the humerus and
the intermuscular septa and descends more distally
than the biceps brachii to continue in a short tendon
which inserts into the coronoid process of the ulna
and the ulnar tuberosis (see Chapter 8). From the
biomechanical point of view, the coracobrachialis
plays a role as an extensor and adductor of the arm,
whereas the brachialis and the biceps brachii are
powerful flexors of the forearm. Furthermore, the
biceps brachii is a supinator of the forearm and a
weak flexor of the arm. US examination of the anterior arm is best performed with the patient lying
supine keeping the arm abducted (Fig. 7.3). Different
degrees of internal and external rotation of the arm
may be helpful in evaluating the anatomic structures placed more laterally and medially. Sweeping
the probe down from the tip of the coracoid, trans-
verse US images demonstrate the coracobrachialis
muscle followed by the two heads of the biceps brachii (Fig. 7.3a–c). More distally, the biceps is seen
overlying the deep brachialis muscle, which rests
over the anterior humeral cortex (Fig. 7.3d,e). The
lateral and medial intermuscular septa separate the
anterior muscles from posterior lateral and medial
heads of the triceps muscle.
Among the four nerves of the arm (median, ulnar,
radial and musculocutaneous), the musculocutaneous is the one crossing the anterior aspect of the arm
(Fig. 7.4a). This nerve arises from the lateral cord
of the brachial plexus (C5–C7 level). It pierces the
coracobrachialis and then descends on the anterior
aspect of the brachialis between this muscle and the
biceps (Fig. 7.4b,c). On transverse US images, the
musculocutaneous nerve can be recognized piercing the coracobrachialis (Fig. 7.3c). Its detection
may be not straightforward in obese patients. After
coursing between the brachialis and biceps brachii
the nerve pierces the superficial fascia of the arm to
enter the subcutaneous tissue and emerge above the
elbow crease as the lateral cutaneous nerve of the
SHB
Deltoid
*
LHB
CBr
a
BB
HH
SubS
CBr
H
b
c
b
BB
c
CBr
Br
CBr
d
Br
H
d
e
e
Fig. 7.3a–e. Anterior muscles and musculocutaneous nerve. a–e Series of transverse 12–5 MHz US images obtained from cranial (a) to caudal (e) over the anterior aspect of the arm. a The coracoid process (asterisk) of the scapula, which is the origin
of the conjoined tendon of the coracobrachialis and the short head of the biceps, appears as a rounded hyperechoic structure
with well-defined posterior acoustic shadowing. b The coracobrachialis muscle (CBr) can be found between the deltoid and
the subscapularis (SubS). The musculocutaneous nerve (arrowheads) is recognized as a thin hypoechoic elongated structure
running just superficial to the medial aspect of the coracobrachialis. HH, humeral head. c At the proximal arm, the long head
(LHB) and the short head (SHB) of the biceps become progressively visible. The smaller belly of the long head lies lateral to the
short head. On these planes, the musculocutaneous nerve (arrowhead) can be seen running inside the coracobrachialis muscle
CBr. H, humerus. d At the mid-arm, the two heads of the biceps muscle (BB) fuse together. The musculocutaneous nerve lies
among the distal part of the coracobrachialis (CBr), the proximal part of the brachialis (Br) and the biceps brachii (BB) muscles.
H, humerus. e At the distal arm, the biceps brachii overlies the large brachialis muscle. The musculocutaneous nerve is found
in the hyperechoic cleavage plane separating these two muscles. The photograph at the bottom right of the figure indicates
probe positioning
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C. Martinoli and S. Bianchi
3
CBr
1
3
3
2
BB
Br
4
a
b
c
forearm. The nerve then divides in two small terminal branches, anterior and posterior. The musculocutaneous nerve supplies the coracobrachialis, the biceps brachii and the brachialis and then
distributes to the skin of the forearm as the lateral
(antebrachial) cutaneous nerve. On the anterolateral
aspect of the arm, the cephalic vein courses over the
superficial fascia and the biceps muscle.
Some anatomic variants can be found at the
anteromedial aspect of the arm. The most common
vascular anomaly is the proximal division of the
humeral artery in the radial and ulnar artery.
Although this variant is not associated with clinical
symptoms, it should be described in the US report as
it can cause problems during attempted catheterization of the humeral artery. Another rare but potentially symptomatic variant is the supracondylar process of the humerus (Fig. 7.5a–c). This bone anomaly
refers to a triangular spur-like process which arises
5–7 cm above the medial epicondyle and is typically oriented distally and medially ending with a
beak-like apex (Sener et al. 1998). The supracondylar process is a primitive remnant present in
climbing mammals encountered in approximately
1% of normal limbs. It is usually found in association with a ligament, commonly known as the ligament of Struthers, which joins its tip with the medial
epicondyle. In these cases, the medial aspect of the
humeral metaphysis and the ligament of Struthers
form the boundaries of an osteofibrous tunnel
which encircles the neurovascular bundle of the
forearm (Fig. 7.5d). The radiographic appearance of
Fig. 7.4a–c. Neurovascular structures of the anterior and
medial aspect of the arm. a Schematic drawing illustrates
the median (1) and ulnar (2) nerves as they descend the
bicipital fossa, a longitudinal groove delimited by the
medial head of the triceps posteriorly and the biceps and
brachialis muscles anteriorly. At the proximal arm, the
median nerve courses lateral to the brachial artery (4)
whereas, at the middle third of the arm, it crosses the artery
to descend medial to it down to the antecubital fossa. b,c
The musculocutaneous nerve (3) is seen piercing (arrowhead) the coracobrachialis muscle (CBr) to enter the anterior compartment of the arm where it lies between the
posterior brachialis (Br) and the superficial biceps brachii
(BB). At the distal arm, this nerve becomes subcutaneous
to divide into its terminal branches
the supracondylar process is characteristic but MR
imaging is the technique of choice to image the ligament (Pecina et al. 2002). At US, transverse planes
are the most adequate to display the supracondylar
process. However, because this bony process is thin,
difficulties may arise when the US beam is perpendicular to it. Tilting the probe anteriorly and posteriorly may be helpful to visualize it based on its
posterior acoustic shadowing. The ligament may be
even more difficult to see with US than the bony process. Once detected, a careful scanning technique
is needed to rule out possible signs of entrapment
of the median nerve and the brachial artery which
course just deep to the ligament. A possible proximal bifurcation of the artery and, occasionally, of
the nerve can be encountered together with supracondylar process (Gunther et al. 1993).
7.2.2
Posterior Arm
The posterior compartment of the arm contains the
large triceps muscle (Fig. 7.6). As its name indicates,
the triceps consists of three heads: long, lateral and
medial. The proximal tendon of the long head arises
from the infraglenoid tubercle of the scapula and
continues down with a large muscle belly located at
the medial aspect of the arm (Fig. 7.6a); the lateral
head and the medial head take their origin from the
posterior aspect of the humerus, the first superior,
the second inferior to the spiral groove of the radial
Arm
Br
T
H
a
a
MN
H
UN
b
c
d
Fig. 7.5a–d. Supracondylar process and ligament of Struthers. a,b Transverse 12–5 MHz US images obtained over the supracondylar region in a patient referring a firm deep-seated local mass. a The brachial artery (open arrowhead) and the median
nerve (curved arrow) are located just superficial to the medial aspect of the humeral shaft (H), between the brachialis (Br) and
the triceps brachii (T) muscles. A small bony spur (double arrow) with posterior acoustic attenuation is shown anterior to the
nerve and the artery. b More accurate probe positioning obtained by tilting the transducer anteriorly reveals a well-defined
hyperechoic bony structure (open arrow) in continuity with the medial cortex of the humerus (white arrow) reflecting the
supracondylar process. Note the close relationship of the bone process with the median nerve (curved arrow), the brachial artery
(open arrowhead) and veins (white arrowheads). c Anteroposterior radiograph of the arm confirms the US diagnosis showing a
typical supracondylar process (arrow). d Schematic drawing demonstrates the supracondylar process (arrow) and the ligament
of Struthers (arrowheads) connecting it with the medial epicondyle. The brachial artery (a) and the median nerve (MN) can
be seen passing through the supracondylar foramen, while the ulnar nerve (UN) lies outside it
RN
RN
LoHT
LaHT
dba
MeHT
*
a
*
b
c
Fig. 7.6a–c. Schematic drawing of a coronal view of the posterior compartment of the arm illustrates the anatomy of the triceps
brachii muscle and the radial nerve from surface (a) to depth (c). a–c The relationships among the three muscle bellies of the
triceps – the long head (LoHT), the lateral head (LaHT) and the medial head (MeHT) – are shown. The bellies of the triceps
muscle have separate origins and coalesce distally in a strong common tendon (asterisk) which inserts onto the posterior aspect
of the olecranon. The long head arises from the infraglenoid tubercle through a strong tendon (black arrow), while the lateral
and medial heads take their origin from the posterior aspect of the humeral shaft, the first above, the second below the spiral
groove. Note the radial nerve (RN, black line) and the satellite deep brachial artery (dba, dashed line) which course from medial
to lateral inside the spiral groove, between the two heads
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C. Martinoli and S. Bianchi
nerve (Fig. 7.6b,c). Distally, the long and the lateral
heads of the triceps converge to insert into a flat
tendon that attaches to the olecranon process (see
Chapter 8); the medial head inserts, for the most
part, directly into the olecranon, but also on the
medial aspect of the distal triceps tendon. The triceps muscle is a powerful extensor of the forearm;
because the long head crosses the shoulder joint, it
also plays a role as an extensor and adductor of the
arm. For an adequate evaluation of the posterior
arm, the patient is asked to sit on the bed with the
examiner behind him/her. A slight degree of elbow
flexion may be useful to stretch the distal myotendinous junction and the triceps tendon. Alternatively, the patient can lie prone, but this position is
less comfortable, particularly for elderly subjects.
Transverse US images are first obtained over the
lateral aspect of the arm to display the lateral head
(Fig. 7.7a,b). Visualization of the superficial long
head and the deep medial head is obtained by shifting the transducer more medially (Fig. 7.7c–e).
The radial nerve originates from the posterior
cord of the brachial plexus (C5–C8) and supplies the
extensor muscles of the upper limb (i.e., the triceps,
the lateral part of the brachialis, the brachioradialis, the forearm extensors) and the skin of the dorsal
forearm and dorsolateral aspect of the hand. After
leaving the axilla, this nerve enters the arm at the
posterolateral aspect of the humeral shaft alongside
the brachial artery, first between the coracobrachialis and the teres major and then between the bellies
of the medial and lateral heads of the triceps. Then,
it winds closely around the posterolateral aspect
of the humeral shaft, passing in the spiral groove
between the long and the lateral heads of the triceps
accompanied by the deep brachial artery and vein
(Fig. 7.6). More distally, the radial nerve pierces the
lateral intermuscular septum and enters the anterior
compartment of the arm coursing between the brachialis and brachioradialis muscles. Transverse US
scans obtained with the patient seated in front of the
examiner with the arm in internal rotation are the
best to demonstrate the radial nerve, which courses
adjacent to the bone along the posterolateral aspect
of the humeral shaft (Fig. 7.8). The brachial artery,
the coracobrachialis and the teres major muscles are
LoHT
LoHT
LoHT
LaHT
LaHT
MeHT
H
a
MeHT
bb
H
LaHT
MeHT
dd
MeHT
ME
H
*
H
c
LaHT
LoHT
LaHT
LE
d
e
c
a
b
e
Fig. 7.7a–e. Triceps muscle. a–e Series of transverse 12–5 MHz US images obtained from cranial (a) to caudal (e) over the posterior aspect of the arm. a At the proximal arm, the long (LoHT) and the lateral head (LaHT) of the triceps can be demonstrated
superficial to the humerus (H). The long head is located medial to the lateral head. b Sweeping the probe down from the level
illustrated in a, the medial head (MeHT) can be seen arising from the posterior aspect of the humerus. It is the deepest component of the triceps. c At the middle arm, the three heads of the triceps dispose in two layers: superficial (including the long
and lateral heads) and deep (consisting of the medial head). In the superficial layer, the eccentric distal aponeurosis of the long
head is seen separating this muscle belly from the lateral head. d Moving the probe down toward the distal third of the arm, the
conjoined tendon (arrowhead) of the long and the lateral heads is progressively appreciated. Observe the superficial position of
this tendon relative to the deep medial head. e A more distal image over the olecranon fossa (asterisk) shows the distal triceps
tendon (arrowhead) and the distal myotendinous junction of the medial and lateral heads. ME, medial epicondyle; LE, lateral
epicondyle. The photograph at the bottom right of the figure indicates probe positioning
Arm
play a role as predisposing causes for nerve disease.
In this clinical setting, US serves as an adjunct to
electrodiagnostic testing and clinical evaluation for
patient’s investigation. This technique also provides
the surgeon with important information concerning
surgical exploration and reconstruction.
7.3.1
Anterior Arm
7.3.1.1
Bicipital Sulcus Pathology
Because the ulnar nerve is relatively unconstrained
in the proximal arm, it is only exceptionally
involved in entrapment syndromes at this site. In
general, compression of this nerve in the upper arm
relates to space-occupying lesions, such as large
aneurysms of the brachial artery or anomalous
muscles (e.g., chondroepitrochlearis muscle). On
the other hand, the median nerve is subject to compression at different levels in the upper arm. Penetrating trauma during falls or glass wounds are
most often responsible for nerve injury (Fig. 7.10).
In these cases, the proximity of nerves and vessels
in the bicipital sulcus leads to complex injuries
with contemporary involvement of the median
nerve, the brachial artery and veins, and possibly the ulnar nerve. Given the complexity of these
traumas, it is not unusual to find patients sutured
for vascular bleeding at the first surgical look and
then submitted to US examination for a missed
nerve transection. In the preoperative assessment
of complete nerve tears, US is an accurate means to
identify the level of the tear and to map the location of the nerve ends, that may be displaced and
retracted from the site of the injury, based on the
identification of hypoechoic stump neuromas. In
this application, US has shown some advantages
over MR imaging as a result of its higher spatial
resolution capabilities for imaging a restricted
area in which many nerves and vessels run close
together. A peculiar type of iatrogenic median
nerve injury can be observed at the midhumerus
following brachial artery catheterization. In addition to traumas, compression of the median nerve
in the bicipital sulcus may also occur at the distal
humerus if a bony spur and ligament is present.
When a mass is palpable over the bicipital sulcus,
US is able to distinguish a neurogenic tumor from
other soft tissue neoplasms based on the continuity of the mass with the parent nerve (Fig. 7.11).
Furthermore, US may identify with certainty which
is the nerve of origin (the median, the ulnar) of a
neurogenic mass: an assessment not always easy on
MR imaging, especially for large-sized tumors.
7.3.1.2
Median Neuropathy Following Brachial Artery
Catheterization
In routine outpatients or in cases in which the femoral approach is not appropriate, the percutaneous
brachial approach is a well-established alternative.
The brachial approach is safe with a low complication rate. Nevertheless, the close proximity of the
*
A
a
b
Fig. 7.10a,b. Median nerve transection at the middle third of the arm in a 14-year-old girl following a glass wound. a Long-axis
15–7 MHz US image over the bicipital sulcus demonstrates the median nerve (arrowheads) ending abruptly (arrows) at the level
of the penetrating trauma. Note the heterogeneous appearance (asterisk) of the overlying subcutaneous tissue. In this particular case, the distal stump of the nerve was identified approximately 4 cm below. b Gross surgical view confirms the complete
transection of the median nerve and the gap intervening between the stumps (arrows) measured preoperatively with US. The
brachial artery (a) was undamaged
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C. Martinoli and S. Bianchi
a
a
T
a
b
*
T
c
Fig. 7.11a–c. Schwannoma of the median nerve at the bicipital fossa. a,b Transverse 15–7 MHz US images obtained a just
proximal to the tumor and b at the tumor level demonstrate an eccentric solid hypoechoic mass (T) in continuity with the
fascicles of the median nerve (arrowheads). In b, note the brachial artery (a) and the ulnar nerve (curved arrow) displaced
by the bulk of the tumor. c, Longitudinal 12–5 MHz US image depicts the tumor (T) connected at both ends with the median
nerve (arrowheads). At its proximal end, the mass is in continuity with a swollen fascicle (asterisk), whereas the other fascicles
(straight arrows) remain unaffected and appear displaced at the periphery of the mass. After surgical resection, pathologic
examination revealed a schwannoma
brachial artery to the median nerve, the mobility
of the brachial artery in the arm, as well as the
winding unpredictable course of the nerve, which
lies at first lateral to the artery and then crosses
to its medial side, allow the possibility of incidental median nerve injury during a catheterization
procedure. This complication seems more likely in
patients under anticoagulation therapy (Chuang et
al. 2002). Clinically, the onset of a neuralgic tingling
sensation and paresthesias radiating from the elbow
to the first three fingers suggests nerve irritation
and damage. Needle injury may result in epineurial
hemorrhage leading to compression of the fascicles
and impaired nerve function (Macon and Futrell
1973). US and Doppler imaging are useful to identify the hematoma enclosed in the epineurium and
the displaced fascicles (Chuang et al. 2002). In this
setting, US may have a role in distinguishing an
epineurial hemorrhage from a traumatic neuroma,
an extrinsic collection or a pseudoaneurysm of
the brachial artery. In epineurial hemorrhage, the
collection is typically aligned between the artery
and the fascicles, which are eccentrically displaced
(Fig. 7.12). On the contrary, traumatic neuromas
appear as fusiform hypoechoic areas encasing most
nerve fascicles but not displacing them. Extrinsic
collections are usually larger in size and may cause
major nerve displacement. Finally, pseudoaneurysms appear as pulsatile sacs in continuity with
the injured artery by means of a neck. Color Doppler
imaging can help the diagnosis by showing whirling
blood flow within the sac and “to-and-fro” waveforms at the arterial neck indicating communication
with the artery (Fig. 7.13). In patients with onset of
neuralgic symptoms, US can successfully guide the
percutaneous aspiration of the hematoma to obtain
an early decompression of the fascicles (Chuang et
al. 2002).
7.3.1.3
Supracondylar Process Syndrome
In individuals with a supracondylar process, the
median nerve and, in rare instances, the ulnar
nerve can be compressed in an osteofibrous tunnel
created by a firm fibrous band with a vertical
course, commonly referred to as the “ligament of
344
C. Martinoli and S. Bianchi
Struthers”, which joins the anomalous bony process and the medial epicondyle. Clinically, this
condition typically affects young sportsmen as a
result of intense muscular activity in the elbow and
forearm and may start with pain and numbness
in the first three fingers and weakness of forearm
muscles innervated by the median nerve (Sener
et al. 1998). US can demonstrate the relationship
of the median nerve with the anomalous bone
and ligament. Although not yet reported in the
radiological literature, displacement of the nerve
by these structures may represent an indicator
of entrapment. Therapy includes excision of the
ligament of Struthers and ablation of the supracondylar process. The brachial artery can also be
compressed by an anomalous insertion of the pronator teres muscle into the supracondylar process
(Talha et al. 1987).
7.3.2
Posterior Arm
7.3.2.1
Spiral Groove Syndrome
Within the spiral groove, the close relationship
of the radial nerve with the humeral cortex and
its fixity as it penetrates the lateral intermuscular
septum makes it vulnerable to extrinsic pressure.
Clinically, radial nerve entrapment at the middle
arm is characterized by combined features of both
superficial radial nerve and posterior interosseous
nerve palsy. Radial nerve palsy essentially results
in wrist-drop due to denervation of the forearm
extensors, whereas the triceps muscle (acting on
forearm extension) is usually spared because its
innervation arises above. Sensory loss over the dorsolateral forearm and hand maybe associated. The
main causes of radial nerve compression in the
spiral groove include axillary crutches, pressure
on a wheelchair armrest and improper positioning of the arm such as occurs when an individual
falls asleep leaning against a hard surface following drug- or alcohol-induced stupor, the so-called
Saturday night palsy. Strenuous physical activity
has also been implicated as a possible cause of
radial nerve injury in patients with fibrous bands
arising from either the lateral or long head of the
triceps. Most of these cases recover fully within a
few days or weeks. Recovery may be delayed by several months and occasionally may be incomplete.
In a more severe traumatic setting, and especially
in patients with closed traction injuries, usually
associated with fractures of the midshaft of the
humerus, there may be direct contusion and laceration of the nerve by fracture fragments. In general,
the surgical outcome of radial nerves lacerated by
tidy wounds or traction is better than that of nerves
damaged by humeral fractures. A severe traction
rupture of the radial nerve, with a gap between
the stumps exceeding 10 cm, is best treated by
musculotendinous flexor-to-extensor transfer.
Furthermore, if the interval since injury exceeds
1 year, transfer is more likely to improve function
(Shergill et al. 2001).
Somewhat similar to other sites of nerve entrapment, the main signs of radial nerve impingement
in the spiral groove are a swollen nerve with a uniformly hypoechoic appearance and loss of the fascicular pattern (Bodner et al. 1999, 2001). In entrapment syndromes due to fibrous bands arising from
the adjacent bellies of the triceps, abrupt changes
in the nerve cross-sectional area at the site of compression and direct visualization of the constricting fibrous band can be seen with US (Fig. 7.14). In
contusion traumas, the nerve fascicles may appear
focally swollen and hypoechoic and the fat space
surrounding the nerve thickened and diffusely
hyperechoic (Fig. 7.15). In malaligned or fragmented fractures of the midshaft of the humerus,
the radial nerve can be seen displaced on the edge
of fracture fragments or pinched in between them
(Fig. 7.16) (Bodner et al. 1999, 2001; Peer et al. 2001;
Martinoli et al. 2004). In addition, it may appear
encased or displaced by a hypertrophied callus and
scar tissue. In the postoperative setting, the radial
nerve may be stretched over orthopedic hardware
for osteosynthesis. In patients with onset of progressive radial nerve palsy after internal fixation of
a humeral shaft fracture with a compression plate,
the conflict of the nerve with the metallic plate
can be nicely depicted and US may be helpful in
deciding whether early surgical treatment has to be
instituted (Peer et al. 2001; Martinoli et al. 2004).
In these cases, US reveals the dislocation of the
compression plate and the thinning or thickening
of the nerve which rides on the detached proximal
end of the plate (Fig. 7.17). These findings indicate
the need for a second surgical look for recovery of
the nerve function. Space-occupying masses arising in the spiral groove are rare and may be nonpalpable even if large due to their deep location.
Similar to the bicipital fossa, neurogenic tumors
involving the radial nerve can be encountered in
the spiral groove area (Fig. 7.18).
Arm
T
T
H
a
H
H
b
c
T
T
d
e
f
Fig. 7.18a–f. Schwannoma of the radial nerve at the spiral groove. a–c Transverse 12–5 MHz US images obtained a just proximal
to the tumor, b at the tumor level and c just distal to the tumor with d–f T2-weighted MR imaging correlation demonstrate a
hyperintense solid mass (T) in continuity with the fascicles of the radial nerve (arrows). Note the close proximity of the mass
and the parent nerve with the humerus (H)
References
Bodner G, Huber B, Schwabegger A et al (1999) Sonographic
detection of radial nerve entrapment within a humerus
fracture. J Ultrasound Med 18:703–706
Bodner G, Buchberger W, Schocke M et al (2001) Radial nerve
palsy associated with humeral shaft fracture: evaluation
with US – initial experience. Radiology 219:811–816
Chuang YM, Luo CB, Chou YH et al (2002) Sonographic diagnosis and treatment of a median nerve epineurial hematoma caused by brachial artery catheterization. J Ultrasound Med 21:705–708
Gunther SF, DiPasquale D, Martin R (1993) Struthers’ ligament
and associated median nerve variations in a cadaveric
specimen. Yale J Biol Med 66:203–208
Macon WL IV, Futrell JW (1973) Median-nerve neuropathy after percutaneous puncture of the brachial artery
in patients receiving anticoagulants. N Engl J Med
288:1396
Martinoli C, Bianchi S, Pugliese F et al (2004) Sonography
of entrapment neuropathies in the upper limb (wrist
excluded). J Clin Ultrasound 32:438–450
Pecina M, Boric I, Anticevic D (2002) Intraoperatively proven
anomalous Struthers’ ligament diagnosed by MRI. Skeletal
Radiol 31:532–535
Peer S, Bodner G, Meirer R et al (2001) Examination of postoperative peripheral nerve lesions with high-resolution
sonography. AJR Am J Roentgenol 177:415–419
Sener E, Takka S, Cila E (1998) Supracondylar process syndrome. Arch Orthop Trauma Surg 117:418–419
Shergill G, Bonney G, Munshi P et al (2001) The radial and
posterior interosseous nerves. J Bone Joint Surg Br 83:646–
649
Talha H, Enon B, Chevalier JM et al (1987) Brachial artery
entrapment: compression by the supracondylar process.
Ann Vasc Surg 1:479–482
347
Elbow
8
Elbow
Stefano Bianchi and Carlo Martinoli
CONTENTS
8.1
Introduction 349
8.2
8.2.1
8.2.1.1
8.2.1.2
8.2.1.3
8.2.2
8.2.2.1
8.2.2.2
8.2.2.3
8.2.2.4
8.2.3
8.2.3.1
8.2.3.2
Clinical Anatomy 349
Joint and Ligament Complexes 350
Elbow Joint 350
Medial Collateral Ligament 351
Lateral Collateral Ligament 351
Muscles and Tendons 352
Anterior Elbow 352
Medial Elbow 353
Lateral Elbow 354
Posterior Elbow 355
Neurovascular Structures 356
Median Nerve and Brachial Artery 356
Radial Nerve and Posterior
Interosseous Nerve 357
8.2.3.3 Ulnar Nerve 357
8.2.4 Bursae 357
8.3
Essentials of Clinical History and
Physical Examination 358
8.3.1.1 Tendon Abnormalities 358
8.3.1.2 Ligament Instability 358
8.3.1.3 Cubital Tunnel Syndrome 358
8.4
8.4.1
8.4.2
8.4.3
8.4.4
Ultrasound Anatomy and
Scanning Technique 359
Anterior Elbow 360
Medial Elbow 363
Lateral Elbow 364
Posterior Elbow 367
8.5
8.5.1
8.5.1.1
8.5.1.2
8.5.2
8.5.2.1
8.5.2.2
8.5.2.3
8.5.3
8.5.3.1
Elbow Pathology 370
Anterior Elbow Pathology 371
Distal Biceps Tendon Tear 371
Bicipitoradial (Cubital) Bursitis 372
Medial Elbow Pathology 376
Medial Epicondylitis (Epitrochleitis) 376
Medial Collateral Ligament Injury 377
Epitrochlear Lymphadenopathies 377
Lateral Elbow Pathology 378
Lateral Epicondylitis 378
S. Bianchi, MD
Privat-docent, Université de Genève, Consultant Radiologist,
Fondation et Clinique des Grangettes, 7, ch. des Grangettes,
1224 Genève, Switzerland
C. Martinoli, MD
Associate Professor of Radiology, Cattedra “R” di Radiologia
– DICMI – Università di Genova, Largo Rosanna Benzi 8, 16132
Genova, Italy
349
8.5.3.2 Lateral Collateral Ligament Injury 380
8.5.3.3 Supinator Syndrome
(Posterior Interosseous Neuropathy) 383
8.5.4 Posterior Elbow Pathology 384
8.5.4.1 Distal Triceps Tendon Tear 384
8.5.4.2 Olecranon Bursitis 386
8.5.4.3 Cubital Tunnel Syndrome 390
8.5.4.4 Ulnar Nerve Instability 392
8.5.4.5 Snapping Triceps Syndrome 394
8.5.5 Bone and Joint Disorders 396
8.5.5.1 Synovitis 396
8.5.5.2 Osteoarthritis and Osteochondral
Damage 400
8.5.5.3 Occult Fractures 401
8.5.5.4 Posterior Dislocation Injury and
Instability 402
8.5.6 Elbow Masses 404
References
405
8.1
Introduction
Being capable of a wide range of hinged and rotational motion, the elbow is intrinsically predisposed
to acute injures and degenerative changes. Although
clinical examination and routine radiography are
essential to evaluate elbow disorders, US has become
increasingly important in the diagnostic investigation of several abnormalities affecting tendons and
muscles, joints, ligaments, nerves and other softtissue structures around the elbow joint. After US
examination, CT and MR imaging may be required
to further address the status of the joint cavity, the
articular cartilage and the bone.
8.2
Clinical Anatomy
A brief description of the complex anatomy of the
elbow with emphasis given to the anatomic features
amenable to US examination, including joints and
ligament complexes, muscles and tendons, neurovascular structures and bursae, is included here.
354
S. Bianchi and C. Martinoli
BT
BRRAD
PRT
a
b
head) at the medial aspect of the coronoid process.
Distally, the pronator teres inserts along the lateral
surface of the radial shaft through a flat tendon
(Fig. 8.5a). The median nerve passes in between the
two bellies of the pronator teres and is separated
from the ulnar artery by the ulnar head of this
muscle (Fig. 8.5). During pronation of the forearm,
the pronator teres works together with the pronator
quadratus. There are four superficial flexor muscles
of the hand and wrist that arise from the common
flexor tendon, arranged from medial or lateral as the
flexor carpi radialis, the palmaris longus, the flexor
digitorum superficialis and the flexor carpi ulnaris.
The flexor digitorum profundus has a separate more
distal origin from the anteromedial aspect of the
ulna, the coronoid process and the anterior surface
of the interosseous membrane. The superficial and
deep flexor muscles are primary flexors of the wrist
and fingers. In addition, the common flexor tendon
provides dynamic support to the underlying ulnar
collateral ligament in resisting valgus stress.
8.2.2.3
Lateral Elbow
The lateral compartment of the elbow includes
the extensor muscles of the wrist and hand that
arise from the lateral epicondyle as the “common
extensor tendon”, the brachioradialis, the extensor
carpi radialis longus and the supinator muscles.
Fig. 8.5a,b. Brachial artery and median nerve. a Same
schematic drawing as Fig. 8.4b after removal of the
distal biceps tendon and the superficial humeral
belly of the pronator teres muscle (1) reveals the
course of the brachial artery (arrowheads) and
the adjacent median nerve (straight arrows) in the
pronator area and beneath the “sublimis bridge”
(curved arrow) of the flexor digitorum superficialis muscle (fds). Br, brachialis muscle; BB, biceps
muscle; 2, deep (ulnar) belly of the pronator teres
muscle. b Gross dissection of the cubital fossa demonstrates the brachial artery (curved arrows) and
the median nerve (straight arrows) as they infold in
the space between the brachioradialis (brrad) and
the pronator teres (prt) muscles. The distal biceps
tendon (bt) has previously been removed
The common extensor tendon is a flattened tendon
which originates from the anterolateral surface of
the lateral epicondyle (Fig. 8.3b). It receives contributions of fibers from four superficial extensor
muscles: extensor carpi radialis brevis, extensor
digitorum communis, extensor digiti minimi and
extensor carpi ulnaris. The extensor carpi radialis
brevis makes up most of the deep articular fibers,
whereas the extensor digitorum contributes to the
superficial portion of the common extensor tendon
(Connell et al. 2001). The extensor digiti minimi
and carpi ulnaris provide only minor components
to the common extensor tendon. Overall, these
muscles act as extensors of the wrist and/or fingers
and also play a role in radial (extensor carpi radialis
brevis) and ulnar (extensor carpi ulnaris) deviation
of the wrist. The common extensor tendon origin
is separated from the joint capsule by the lateral
ulnar collateral ligament (Fig. 8.3b). Cranial to and
separately from the common extensor tendon, the
brachioradialis (anterior) and the extensor carpi
radialis longus (posterior) muscles arise from the
supracondylar ridge of the humerus and the lateral
intermuscular septum. The supinator is the deepest of the lateral muscles. It has two heads between
which the posterior interosseous nerve, motor
branch of the radial nerve, passes to reach the posterior elbow (Fig. 8.6a) (see also Sect. 8.2.3.2). The
superficial head arises from the lateral epicondyle,
the lateral collateral and annular ligaments and
from behind the supinator crest and fossa of the
356
S. Bianchi and C. Martinoli
ME
tm
LE
O
TT
T
FCU
FCU
a
fcu
O
ME
b
c
d
Fig. 8.7a–d. Ulnar nerve and cubital tunnel. a Photograph of the posteromedial aspect of the elbow illustrates the course of the
ulnar nerve (dashed black line) between the bony prominences of the medial epicondyle (ME) and the olecranon (O) covered
by the cubital tunnel retinaculum (dark gray) and, more caudally, by the aponeurosis and the belly of the flexor carpi ulnaris
muscle (light gray). LE, lateral epicondyle. b Schematic drawing of the cubital tunnel on cross-section view reveals the relationships of the ulnar nerve (arrow) with the medial epicondyle (ME) and the olecranon (O). Note the Osborne retinaculum that
covers the cubital tunnel as a roof. c Schematic drawing of the posterior aspect of an extended elbow demonstrates the ulnar
nerve (arrows) as it passes through the cubital tunnel, beneath the Osborne retinaculum (dark gray) and the flexor carpi ulnaris
muscle (fcu, light gray). tm, triceps muscle; T, distal triceps tendon. d Gross dissection of the cubital tunnel shows the triangular
arcuate ligament that unites the humeral (fcu1) and ulnar (fcu2) heads of the flexor carpi ulnaris muscle. The forceps elevate the
ligament making the course of the nerve (arrows) visible
8.2.3
Neurovascular Structures
The elbow is traversed by the ulnar, median and radial
nerves that cross through its posteromedial, anterior
and lateral aspects respectively. In the elbow area, the
median nerve is accompanied by the brachial artery,
the radial nerve gives off a main motor branch, the
posterior interosseous nerve, and the ulnar nerve travels across an osteofibrous tunnel, the cubital tunnel.
8.2.3.1
Median Nerve and Brachial Artery
In the cubital fossa, the median nerve courses behind
the lacertus fibrosus and superficial to the brachialis
muscle. More distally, it progressively deepens to
pass between the ulnar and humeral heads of the
pronator teres muscle in more than 80% of individuals. At the elbow, the median nerve gives off small
muscular branches to the pronator teres, palmaris
longus, flexor carpi radialis and flexor carpi ulnaris.
Then, it courses deep to the tendinous bridge connecting the humero-ulnar and radial heads of the
flexor digitorum superficialis muscle, the so-called
sublimis bridge (Fig. 8.5).
At the elbow, the brachial artery is superficial and
courses along the medial border of the biceps muscle
and tendon overlying the brachialis (Figs. 8.4b,c, 8.5).
Then, it passes between the median nerve (medial)
and the biceps tendon (lateral) beneath the bicipital
aponeurosis to divide, at the proximal forearm, into
the radial and ulnar arteries.
358
S. Bianchi and C. Martinoli
8.3
Essentials of Clinical History
and Physical Examination
In the history of the patient complaining of elbow
pain or dysfunction the examiner has to consider
possible systemic articular diseases (rheumatoid
arthritis and similar conditions), occupational
disorders (drill diseases which can cause joint
osteoarthritis) and traumas (missed radial head
fractures may be a cause of long-lasting discomfort), even if sustained in the past. Sport activities
are also a critical part of the history: tennis and
golf practice can cause microtrauma and overuse
injuries to the common extensor and flexor tendon
origins with the onset of clearly defined clinical
syndromes. With chronic symptoms, it is important to analyze as accurately as possible how the
pain radiates and where it is localized, as well as
its eliciting factors, because these characteristics
can help to focus the US examination and suggest
the correct diagnosis.
At physical examination, the range of elbow
motion and the end-point of motion must be investigated at the level of both the radio-capitellar and
trochlea-ulnar joints (flexion/extension) as well as
at the proximal radio-ulnar joint (pronation/supination). Then, previous standard radiographs, if any,
must be reviewed before starting the US examination in order to exclude bone abnormalities that may
be overlooked or misinterpreted at US, such as joint
erosions, osteoarthritic changes and heterotopic
calcifications. In a post-traumatic setting, a careful
review of the radiographs should be obtained prior
to the US examination to rule out subtle fractures,
especially involving the radial head, that may be
overlooked at first observation.
8.3.1.1
Tendon Abnormalities
When a tendon lesion is suspected, specific resisted
movements must be checked. Due to its superficial position, the distal biceps tendon can easily
be palpated during resisted flexion while keeping
the elbow 90° flexed and supinated. The rupture of
this tendon is typically associated with retraction
of the muscle into the arm, where it can be appreciated as a lump (see Sect. 8.5.1.1). Nevertheless, the
retracted muscle belly can be difficult to detect
in obese patients or when local swelling and pain
limit proper physical examination. The distal triceps tendon can also be palpated without difficulty
on the posterior elbow with the joint 90° flexed. Its
integrity can be assessed by asking the patient to
extend the elbow against resistance: a complete tear
of the distal triceps tendon causes complete loss of
extension power (see Sect. 8.5.4.1). In the case of
a patient with suspected lateral epicondylitis, the
examiner should immobilize the patient’s elbow
with one hand while compressing the common
extensor tendon origin with the fingers over the
lateral epicondyle. In lateral epicondylitis, this
maneuver elicits pain radiating from the epicondylar area down through the forearm. Pain is typically exacerbated by extending the wrist against
resistance (see Sect. 8.5.3.1). In medial epicondylitis, pain can be elicited by firm pressure over the
medial common tendon or by resisted wrist flexion
(see Sect. 8.5.2.1).
8.3.1.2
Ligament Instability
Specific clinical tests may be helpful in the setting
of ligament instability. To evaluate the integrity
of the lateral and medial collateral ligaments, the
examiner may grasp the posterior aspect of the
patient’s elbow with one hand and the patient’s
wrist with the other. While locking the elbow, a
valgus or varus stress is applied to assess the integrity of the medial and lateral collateral ligaments
respectively. These clinical maneuvers are more
reliably performed by placing the probe over the
ligament in order to demonstrate even minor widening of the joint space during stressing (Fig. 8.9)
(see Sects. 8.5.2.2, 8.5.3.2).
8.3.1.3
Cubital Tunnel Syndrome
A useful clinical maneuver to assess the state of
the ulnar nerve is the “Froment’s test”. The patient
is asked to pinch a sheet of paper between thumb
and index finger. In case of overt ulnar neuropathy,
the patient grasps the paper by flexing the thumb
(activation of the median-innervated flexor pollicis
longus as a compensation for the weakness of dorsal
interosseous muscles) (see Sect. 8.5.4.3). In patients
with cubital tunnel syndrome, palpation of the ulnar
nerve at the cubital tunnel may be painful and may
reproduce symptoms.
360
S. Bianchi and C. Martinoli
8.4.1
Anterior Elbow
US examination of the anterior elbow may be performed with the patient facing the examiner with
the elbow extended resting on a table (Barr and
Babcock 1991). A slight bending of the patient’s body
towards the examined side makes full supination and
assessment of some structures of the anterior compartment, such as the distal biceps tendon, easier.
A full elbow extension can be obtained by placing a
pillow under the joint. Raising the table can also be
helpful and allows for a more comfortable examination for both the patient and the examiner. If the
patient is unable to obtain a complete elbow extension, longitudinal scans can be difficult to perform,
particularly when using large-sized probes. As an
alternative in the elderly or for severely traumatized
patients, the anterior aspect of the elbow can also be
examined with the patient supine holding his or her
arm along the body.
The main anterior structures amenable to US
examination are: the brachialis muscle, the distal
biceps muscle and tendon, the brachial artery, the
median and radial nerve, the anterior synovial recess
with the anterior fat pad and the radio-capitellar
and trochlea-ulna joints. Transverse US images are
first obtained by sweeping the probe from approximately 5 cm above to 5 cm below the trochlea-ulna
joint, perpendicular to the humeral shaft. Cranial
US images of the supracondylar region reveal the
two main muscles of the anterior aspect of the distal
arm: the superficial biceps muscle and the deep
brachialis muscle (Fig. 8.10a). The biceps lies just
deep to the subcutaneous tissue surrounded by the
brachial fascia. It has a bipennate appearance with
a central hyperechoic layer reflecting the aponeurosis. The brachialis muscle is located between the
biceps and the humeral bony cortex and is much
larger than the biceps. The brachial artery and the
median nerve course alongside these muscles: the
artery typically lies lateral to the nerve (Fig. 8.10b).
Shifting the transducer more distally, the distal
biceps tendon appears as a hyperechoic structure
that overlies the brachialis muscle (Fig. 8.10b,c). A
careful scanning technique is required to image this
tendon. The distal biceps tendon is best examined
on longitudinal planes with the patient’s forearm in
maximal supination to bring the tendon insertion
on the radial tuberosity into view (Fig. 8.11) (Miller
a
br
a
a
br
b
a
br
c
R
U
Fig. 8.10a–c. Normal distal biceps tendon. Transverse 12−5 MHz US images obtained over the
anterior elbow in a healthy subject demonstrate
the distal biceps tendon: a at the myotendinous
junction, b at the level of the humeral trochlea
and c below the joint line, just before its insertion.
In a, the distal biceps tendon takes its origin from
a wide echogenic aponeurosis (arrowheads) that
is located centrally within the muscle (arrows).
Note the brachialis muscle (br) that lies deep
to the biceps. a, brachial artery. In b and c, the
distal biceps tendon (large arrow) appears as an
oval hyperechoic structure that lies superficial to
the brachialis (br). Close to its medial side, the
brachial artery (a) and the median nerve (curved
arrow) are seen, whereas the radial nerve (small
arrow) lies more laterally between the brachialis
and brachioradialis muscles. Note the aponeurosis (arrowheads) of the brachialis R, radius; u,
ulna. The inserts at the upper left side of the figures indicate probe positioning
Elbow
S
Br
∗
RH
HC
?
★
a
?
★
Br
RH
HC
b
c
Fig. 8.11a–c. Normal distal biceps tendon. a Long-axis 12−5 MHz US image of the anterior elbow with b sagittal T1-weighted
(T1w) SE MR imaging correlation shows the curved appearance of the distal biceps tendon (arrows) that inserts on the bicipital
tuberosity (asterisk) of the radius. The tendon has a fibrillar appearance and courses superficial to the brachialis (Br) and the
supinator (S) muscles. Observe the squared appearance of the radial head (RH), the rounded humeral capitellum (HC) covered
by a band of hypoechoic cartilage and the anterior fat pad (stars). c Photograph illustrating the scanning technique to image
the distal portion of the biceps tendon. The patient’s forearm is kept in maximal supination (curved arrow) and the inferior
edge of the transducer is pushed against the patient’s skin.
and Adler 2000). Because of an oblique course from
surface to depth, portions of this tendon may appear
artifactually hypoechoic if the probe is not maintained parallel to it (Fig. 8.12a,c). Accordingly, the
distal half of the probe must be gently pushed against
the patient’s skin to ensure parallelism between the
US beam and the distal biceps tendon, thus allowing a complete visualization of its echogenic fibrillar pattern (Fig. 8.12b,d). In thick large elbows,
however, the distal portion of this tendon may be
difficult to examine owing to its deep location. In
general, transverse planes are less useful for examining the distal part of the biceps tendon because
slight changes in transducer orientation may produce dramatic variation in tendon echogenicity and
this create confusion between the tendon and the
surrounding strucutres. In conditions of maximal
anisotropy, the tendon and the artery may exhibit
the same size and echogenic pattern on transverse
scans (Fig. 8.12e,f).
As stated earlier, the median nerve courses on
the internal side of the brachial artery, whereas the
radial nerve can be appreciated between the brachioradialis and the brachialis muscle (Figs. 8.10b,c;
8.13). The coronoid fossa appears as a concavity
of the anterior surface of the humerus filled with
hyperechoic tissue related to the anterior fat pad
(Fig. 8.14). The fat pad has a triangular shape with
its base located anteriorly, deep to the brachialis
muscle. At this level, the anterior capsule is imaged
inconsistently with US (Miles and Lamont 1989).
In normal states, a small amount of fluid can be
recognized between the fat pad and the humerus
(Fig. 8.14). On transverse US images, the anterior
aspect of the distal humeral epiphysis appears as a
wavy hyperechoic line covered by a thin layer (2 mm
thick) of hypoechoic articular cartilage (Fig. 8.15).
Its lateral third corresponds to the humeral capitellum that shows a typical convex shape and articulates with the radial head. The medial two thirds of
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S. Bianchi and C. Martinoli
v
a
c
e
v
b
a
d
a
f
Fig. 8.12a–f. Normal distal biceps tendon and anisotropy. a,b Schematic drawings and c,d corresponding long-axis 12-5MHz
US images of the biceps tendon obtained with oblique (a,c) or perpendicular (b,d) incidence of the US beam. e,f Respective
short-axis scans. In c and e, an inadequate orientation of the US beam leads to a hypoechoic appearance of the tendon (arrows)
relative to the surrounding fat due to anisotropy. When incorrectly imaged, the tendon can be distinguished from the adjacent
brachial artery (a) and cubital vein (v) with difficulty because all look hypoechoic
br
br
HC
a
BR
BR
b
2(
(#
Fig. 8.13a,b. Median nerve and brachial artery. Longitudinal gray-scale
(a) and color Doppler (b) 12−5 MHz
US images over the antecubital fossa
demonstrate the normal appearance
of the median nerve (white arrows
in a) and the brachial artery (open
arrows in b). Both lie superficial to
the brachialis muscle (br). Note the
humeral capitellum (HC) and the
radial head (RH). The inserts at the
upper left side of the figures indicate
probe positioning
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S. Bianchi and C. Martinoli
∗∗
br
br
Ulna
Ulna
∗
a
br
br
br
br
∗
∗
b
The common flexor tendon is best examined
in longitudinal planes. It appears shorter than the
common extensor tendon origin and inserts onto the
medial aspect of the epitrochlea (Fig. 8.17a). Deep to
this tendon, the anterior bundle of the medial collateral ligament appears as a cord-like structure that
joins the epitrochlea with the more cranial aspect of
the ulna, the so-called sublimis tubercle (Fig. 8.17a,b).
The proper positioning for examination of the anterior bundle of the medial collateral ligament is
obtained with the patient supine keeping the shoulder abducted and externally rotated and the elbow
in 90° of flexion (Ward et al. 2003). At US examination, the anterior component of the medial collateral
ligament has a fibrillar pattern and a fanlike shape
(Ward et al. 2003). It looks hyperechoic: however,
the ligament echogenicity may vary depending on
patient and probe positioning (Fig. 8.17a,b). With the
patient’s elbow in the extension position lying on the
examination table, it usually appear hypoechoic in
comparison with the overlying flexor tendon. In a
recent US study with cadaveric correlation, the ligament thickness was reported to range from approximately 2.6 to 4 mm, without significant differences
in sidedness, stress application or hand dominance
(Ward et al. 2003). The other components of this ligament, namely the posterior and transverse bundles,
are not depicted as accurately as the anterior one on
br
br
c
Fig. 8.16a,c. Brachialis tendon. a Mid-sagittal
12−5MHz US image of the antecubital fossa with
b T1w SE MR imaging and c diagram correlation
shows the brachialis tendon (arrow) as a short
and thick structure which inserts on the anterior
ulna, just caudal to the apex (asterisk) of the coronoid process. br, brachialis muscle; arrowheads,
distal biceps tendon. The insert at the upper left
side of the figure indicates probe positioning
US examination, even using high-resolution transducers. However, these latter portions are a less frequent source of morbidity and play a minor role in
stabilizing the elbow against valgus stress.
8.4.3
Lateral Elbow
The lateral aspect of the elbow is best examined with
both elbows in extension, thumbs up, palms of the
hands together (Barr and Babcock 1991). When
examining the radial collateral ligament and the capsule, the elbow should be extended, keeping the hand
pronated. Along the lateral elbow, high-resolution US
can demonstrate the common extensor tendon, the
lateral ulnar collateral ligament, the radial nerve with
its superficial and deep (posterior interosseous nerve)
branches, and the radio-capitellar joint.
The common extensor tendon origin is best
visualized in longitudinal planes as a beak-shaped
hyperechoic structure located between the subcutaneous tissue and the lateral ulnar collateral ligament
(Fig. 8.18). Deep to this tendon, the lateral epicondyle appears as a smooth down-sloping hyperechoic
structure. The individual contributions from the
extensor muscles to the common extensor tendon
cannot be discriminated with US because they are
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S. Bianchi and C. Martinoli
interwoven with each other. The deep tendon fibers
relative to the extensor carpi radialis brevis overlie the lateral ulnar collateral ligament and cannot
easily be separated from it. In fact, these structures
are intimately related and, although they run in a
slightly different direction, they have the same fibrillar appearance (Connell et al. 2001). On transverse
US images, the common extensor tendon origin has
an oval cross-sectional shape and is located just
superficial to the lateral epicondyle. Immediately
distal to the myotendinous junction, the muscular
bellies of the extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi and extensor
carpi ulnaris usually appear as a single bulk.
Anterior to the lateral epicondyle, the main trunk
of the radial nerve courses between the brachialis
and the brachioradialis muscles. It is reliably exam-
ined by means of transverse US images obtained
between these muscles as a small rounded structure composed of a few scattered hypoechoic dots
reflecting the fascicles (Fig. 8.19a) (Bodner et al.
2002). The recurrent radial artery can be seen adjacent to the nerve and should not be confused with
one of its fascicles. Color Doppler imaging may be
helpful to precisely identify it. High-resolution US
is able to visualize the radial nerve as it divides
into the superficial cutaneous sensory branch and
the posterior interosseous nerve (Fig. 8.19b,c). The
fascicles in these latter nerves are very small and
a meticulous scanning technique based on tracking the nerve bundle according to its short axis is
needed for their visualization. At the lateral elbow,
US can visualize the posterior interosseous nerve as
it pierces the supinator muscle and enters the arcade
brrad
br
HC
a
br
RH
b
s
c
RN
Fig. 8.19a–c. Radial nerve. Transverse
12−5 MHz US images obtained over the
anterolateral elbow demonstrate the normal
radial nerve and its divisional branches at the
level of humeral capitellum (a), radial head (b)
and radial neck (c). In a, the main trunk of
the nerve (arrow) lies in the hyperechoic space
between the brachialis (br) and brachioradialis (brrad) muscles, superficial to the humeral
capitellum (HC). In b, the radial nerve (arrow)
passes over the radial head (RH) in close relation to the annular ligament (arrowheads).
Typically, this ligament appears as a curved
hyperechoic band that covers the radial head
like a belt. In c, the cutaneous sensory branch
(straight arrow) and the posterior interosseous nerve (curved arrow) can be appreciated
over the supinator muscle (s) as a result of
bifurcation of the main trunk of the nerve. RN,
radial neck. The inserts at the upper left side of
the figures indicate probe positioning
Elbow
of Frohse, passing between the superficial and deep
parts of this muscle (Fig. 8.20). Across the supinator, the nerve moves toward the posterior compartment. Accordingly, an appropriate scanning technique should include repositioning of the patient
with the elbow in semiflexion, placing the forearm
forward and more transversely oriented over the
examination table. During pronation, the nerve may
assume an angulated course at the proximal edge of
the arcade of Frohse. One should not mistake this
appearance for a pathologic finding. Within or just
after leaving the supinator muscle, the posterior
interosseous nerve can be seen further subdividing
into a few subtle branches directed to the muscles
of the posterior forearm. These latter branches are
difficult to examine because their size approximates
the spatial resolution capability of current US equipment. Once given off anterior to the lateral epicondyle, the superficial cutaneous sensory branch of the
radial nerve continues into the anterior forearm. At
the proximal forearm, it joins the radial artery and
can be demonstrated coursing between the extensor
carpi radialis longus and the brachioradialis.
The lateral aspect of the radio-capitellar joint can
clearly be delineated with US (Fig. 8.18a). A triangular hyperechoic structure is usually seen filling the
peripheral portion of the articular rim between the
two bony surfaces. This structure corresponds to a
synovial projection, somewhat similar to a meniscus (lateral synovial fringe) (Fig. 8.18a). The appearance of the radial head varies with different degrees
of rotation of the forearm: in pronation, the radial
head has a more squared appearance, whereas in
supination it tends to assume a smoother contour.
Dynamic US scanning may be helpful to assess the
status of the radial head and to exclude possible
occult nondisplaced fractures. Superficial to it, the
annular ligament is visible as a belt-like homogeneous hyperechoic structure (Fig. 8.19b). It is best
visualized by means of high-resolution transducers.
With the probe placed over the radial head, passive
supination and pronation movements of the forearm
allow a better differentiation of the fixed annular
ligament from the rotating radial head. At the radial
metaphysis, the annular recess is visualized with US
only if distended by fluid.
8.4.4
Posterior Elbow
The posterior aspect of the elbow may be examined
by keeping the joint flexed 90° with the palm resting
on the table (Barr and Babcock 1991). This posi-
brrad
ss
ss
ds
ds
Radius
a
brrad
ss
ds
ds
b
Fig.8.20a,b. Posterior interosseous nerve.
a Long-axis and b short axis 12−5 MHz
US images obtained at the proximal
forearm over the brachioradialis muscle
(brrad) demonstrate the normal posterior interosseous nerve as it crosses the
supinator muscle. Within the bellies of
the supinator (ss, superficial part of the
supinator muscle; ds, deep part of the
supinator muscle), the nerve appears as
a thin hypoechoic structure composed
of a few fascicles (arrows) embedded in
a hyperechoic fatty plane. The inserts at
the upper left side of the figures indicate
probe positioning
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S. Bianchi and C. Martinoli
tion allow easy demonstration of the main structures of the posterior elbow: the cubital tunnel and
the ulnar nerve, the triceps muscle and tendon, the
posterior fossa with the posterior fat pad and the
olecranon bursa.
Cranial to the olecranon, US reveals the hypoechoic bellies of the triceps muscle and its tendon
that is located eccentrically and slightly medial with
respect to the midline (Fig. 8.21). The distal triceps
tendon appears hyperechoic and typically exhibits
striations as it fans out toward its insertion on the
olecranon, a pattern somewhat similar to the quadriceps. These striations, with alternating hypo- and
hyperechoic bands, are more likely due to interposition of fat between the tendon fibers and should not
be misinterpreted as tendinosis or tear (Fig. 8.22). If
examined in full elbow extension, the distal triceps
tendon may also appear wavy, possibly mimicking a
rupture. Tendon laxity is particularly evident in the
elderly and represents a normal finding (Rosenberg
et al. 1997). In addition, the preinsertional fibers of
this tendon may appear hypoechoic owing to their
oblique course (Fig. 8.22). Changes in orientation of
the probe allow adequate correction of anisotropic
effects in this area. The most distal portion of the
triceps tendon should always be evaluated carefully
to rule out enthesis calcifications.
The olecranon fossa appears as a wide and deep
concavity of the posterior aspect of the humeral
shaft filled with the hyperechoic posterior fat pad
(Fig. 8.21a) (Miles and Lamont 1989). At both
sides of this fossa, the posterior aspect of the medial
and lateral epicondyles can be seen on transverse
images. While examining the joint at 45° flexion,
intra-articular fluid tends to move from the anterior
synovial space to the olecranon recess, thus making
the identification of small intra-articular effusions
easier. Gentle rocking motion of the patient’s elbow
during scanning may be helpful to shift elbow joint
fluid into the olecranon recess. More distally, the
tm
tm
✟
★
O
c
b
∗
∗
T
a
HS
O
T
b
c
Fig. 8.21a–c. Normal distal triceps tendon and olecranon fossa. a Extended-field-of-view mid-sagittal 12−5 MHz US image
obtained with the elbow flexed over the olecranon process (O) and the posterior aspect of the distal humerus. The distal triceps
tendon (arrowheads) appears as a beak-shaped hyperechoic structure in continuity with the hypoechoic bellies of the triceps
muscle (tm) that inserts approximately 1 cm distal to the apex (star) of the olecranon. Deep to the triceps, the olecranon fossa
is delimited by the hyperechoic spoon-shaped contour of the humerus and the echogenic posterior fat pad (asterisks). Note the
posterior rounded appearance of the trochlea (T) and the straight profile of the humeral shaft (HS) just above the posterior
fossa. b,c Transverse 12−5 MHz US images obtained at the levels (vertical white bars) indicated in a. In b, the cross-sectional
appearance of the distal myotendinous junction of the triceps is seen over the posterior trochlea (T). Observe that the tendon
(curved arrow) arises slightly eccentrically relative to midline and the distal muscle (arrowheads). In c, the oval cross-sectional
shape of the distal triceps tendon (arrows) is seen lying over the olecranon (O). The insert at the upper left side of the figure
indicates probe positioning
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S. Bianchi and C. Martinoli
the inside slope of the medial epicondyle. It typically
appears as an ovoid structure close to the hyperechoic bony cortex of the epicondyle (Fig. 8.24a,b).
In the distal portion of the tunnel, the ulnar nerve
is visible between the humeral and ulnar heads of
the flexor ulnaris carpi muscle (Fig. 8.24c,d). In
normal states, the cross-sectional area of the ulnar
nerve is slightly greater at the level of the epicondyle (6.8 mm 2) than at the distal arm (5.7 mm 2) and
the proximal forearm (6.2 mm2) (Chiou et al. 1998).
One should be careful not to confuse this normal
increase in nerve size inside the cubital tunnel for
a sign of ulnar neuropathy. Some discrepancies
exists in literature on as what the size of the ulnar
nerve should be considered normal. A cross-sectional area of ⱖ7.5mm 2 was initially indicated as
the threshold value for the cubital tunnel syndrome
(Chiou et al. 1998). More recently, 7.9mm 2 has
been found as the mean value for the normal ulnar
nerve at the cubital tunnel level (Jacob et al. 2004).
These discrepancies seem, at least in part, related
to differences among races and in study design. In
the cubital tunnel, the ulnar recurrent artery and
veins can readily be distinguished from the adjacent nerve on color Doppler imaging. In cases of
engorgement, these veins become dilated and could
mimic swollen individual nerve fascicles. Doppler
ME
imaging can help to avoid this pitfall. The cubital
tunnel retinaculum and the arcuate ligament consist of thin fascia and, at least in normal states, they
are not visualized with US, even using very high
frequency US transducers. Dynamic imaging of the
cubital tunnel is performed throughout full elbow
flexion to assess the position of the ulnar nerve
and the medial head of the triceps muscle relative
to the medial epicondyle (see Sects. 8.5.4.4, 8.5.4.5)
(Fig. 8.25). For this purpose, the probe is placed in
the transverse plane over the epicondyle while the
patient is asked to slowly flex the elbow (Jacobson
et al. 2001). During this maneuver, it should be
emphasized that the application of firm pressure
on the skin with the transducer must be avoided
because it may prevent the dislocation of the nerve
from the tunnel.
8.5
Elbow Pathology
A variety of disorders can involve the soft tissues
of the elbow. Multiple conditions related to specific
anatomic sites may exhibit overlapping symptoms
and are easily confused clinically.
∗
ME
∗
O
a
fcu11
fcu
fcu22
fcu
fcu
Ulna
Ulna
c
O
b
fcu
Ulna
d
Fig. 8.24a–d. Normal cubital tunnel. a Transverse 12−5 MHz US image at the proximal cubital tunnel level (condylar groove)
with b T1w SE MR imaging correlation show the normal relationship of the ulnar nerve (arrow) with the medial epicondyle
(ME). Observe the distal triceps tendon (asterisks) over the olecranon (O). c Transverse 12−5 MHz US image at the distal cubital
tunnel level (proper cubital tunnel) with d T1w SE MR imaging correlation demonstrates the nerve (arrow) beneath the arcuate
ligament (arrowheads) that joins the humeral (fcu1) and ulnar (fcu2) heads of the flexor carpi ulnaris muscle. The inserts at the
upper left side of the figures indicate probe positioning
Elbow
a
c
b
d
Fig. 8.25a–d. a,b Photographs illustrating the scanning technique to assess the position of the right ulnar nerve relative to the
medial epicondyle with elbow extension (a) and during progressive degrees of elbow flexion (b). Note that the probe remains
stabilized on transverse plane between the medial epicondyle and the olecranon during full elbow motion. c,d Schematic drawings of the medial elbow examined in c extension and d flexion illustrate the mechanism of ulnar nerve instability at the cubital
tunnel. Note the absence of the Osborne retinaculum (see for comparison Fig. 8.7c). When the elbow is extended, the ulnar nerve
(white arrow) is contained within the tunnel. Elbow flexion (black arrow) dislocates the ulnar nerve anteriorly to the medial
epicondyle (ME). fcu, flexor carpi ulnaris muscle. Dashed line, appropriate probe positioning during scanning
8.5.1
Anterior Elbow Pathology
8.5.1.1
Distal Biceps Tendon Tear
One of the most common causes of acute anterior elbow
pain is rupture of the distal biceps tendon. These tears
account for less than 5% of all biceps tendon lesions,
proximal injuries being far more common (Agins et
al. 1988). They typically occur after 40 years of age
(mean 55 years) in manual laborers who attempt to
lift a heavy object (or in weightlifters and body builders) or during vigorous eccentric contraction of the
biceps against resistance. Distal biceps tendon tears
may occur with either avulsion of the tendon by the
radial tuberosity (more commonly) or midsubstance
tear or injury at its myotendinous junction. Similar
to other tendons, there is a relatively hypovascular
zone within the distal biceps tendon, approximately
10 mm from its insertion on the radial tuberosity
(Seiler et al. 1995). Repetitive impingement of this
zone between the radius and the ulna during pronation movements seems to be a predisposing factor
to start the degenerative process in the tendon sub-
stance (Seiler et al. 1995). In most cases, the rupture
of the distal biceps tendon is associated with tearing
of the lacertus fibrosus, but this latter structure may
also remain intact. Clinically, a complete tendon tear
presents with pain and a palpable defect with a proximal lump in the anterior aspect of the arm related to
the retracted muscle (Fig. 8.26). Although weakened,
elbow flexion is preserved due to the strong action of
the brachialis muscle; on the contrary, supination of
the forearm is more severely compromised because of
the limited strength of the small supinator muscle. In
most cases, the clinical diagnosis is straightforward
and does not require an additional imaging study.
Nevertheless, occult ruptures are more common than
once thought and, in daily practice, they are becoming increasingly diagnosed with US even some time
after the trauma. A delayed clinical diagnosis occurs
mainly in the absence of significant muscle retraction because of an intact lacertus fibrosus, or when
the retracted muscle is hidden from palpation with
surrounding edema and hemorrhage.
An early diagnosis of distal biceps tendon rupture
is important because surgical outcome is improved
in patients treated in the first weeks after trauma
before the occurrence of tendon adhesions, degenera-
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S. Bianchi and C. Martinoli
a
b
Fig. 8.26a,b. Distal biceps tendon tear: physical findings. Photographs of two different patients who underwent a subacute and
b chronic complete rupture of the distal biceps tendon. In a, the patient injured his left tendon while attempting to lift a heavy
object. He presented with hemorrhagic skin over the medial elbow and proximal forearm and with a proximal lump (arrowheads) in the anterior aspect of the arm related to the retracted muscle. In b, the patient was a competitive body-builder who
refused surgical repair of the ruptured tendon. Note the defect (arrowhead) in the anterior left arm due to the retracted muscle
in comparison with the right side
tive changes and fatty muscle infiltration. The main
US features of a complete tear of the distal biceps
tendon include nonvisualization of the distal tendon,
which appears proximally retracted (up to more
than 10 cm from the radial tuberosity), and detection of hypoechoic fluid in the tendinous bed related
to hematoma (Fig. 8.27) (Lozano and Alonso 1995;
Miller and Adler 2000). The effusion is best recognized around the tendon stump (Fig. 8.28). With highresolution transducers, US is not sensitive enough to
can depict the normal lacertus fibrosus as a very thin
fibrillar band over the pronator teres. The status of the
lacertus fibrosus is, however, not a critical issue as it is
not routinely involved in surgical repair of a torn distal
biceps tendon. In addition, there is no evidence that the
degree of tendon retraction is in itself predictive of the
status of the lacertus fibrosus (Fig. 8.29) (Miller and
Adler 2000). In case of its rupture, however, US can
recognize perifascial fluid around the anterior and
lateral aspects of the flexor-pronator group of muscles
and a more striking tendon retraction (Fig. 8.29b).
The less common tendinitis and partial tears of
the distal biceps tendon present with localized pain
and tenderness over the antecubital fossa. These
conditions usually follow repetitive microtrauma or
forceful biceps activation. Pain can be exacerbated
during resisted elbow flexion or supination of the
hand and is worsened by direct palpation of the
tendon. At US, partial tears appear as hypoechoic
thickening or thinning of the tendon and as contour
irregularities or waviness without tendon discontinuity (Fig. 8.30) (Miller and Adler 2000). The
assessment of these tears may be difficult with US
due to anisotropy related to the oblique course of the
tendon and to its deep position. The US appearance
of biceps tendinitis is very similar to that of partial
tears and the diagnostic accuracy of US for differentiating these conditions relies on availability of
a high-quality transducer as well as on the overall
experience of the examiner. In doubtful cases, MR
imaging is an accurate means to confirm the diagnosis of partial tears (Falchook et al. 1994).
Surgical treatment in complete tendon tears
includes repair and reattachment of the retracted
tendon to the radial tuberosity or, alternatively, to
the brachialis muscle or the ulnar tuberosity. The
first technique gives better results in restoring supination but has a significantly higher risk of radial
nerve injury. After surgery, the tendon appears
thickened and hypoechoic with internal linear
hyperechoic images related to sutures (Fig. 8.31).
8.5.1.2
Bicipitoradial (Cubital) Bursitis
The distal biceps tendon is not invested by a synovial
sheath but it is covered by a paratenon. Just proximal to
the tendon insertion, it is in contact with the bicipitoradial (cubital) bursa. This bursa is located between the
Elbow
dbt
∗
∗
∗
∗∗
br
br
b
a
∗∗
dbt
d
c
∗
brrad
brrad
br
br
b
∗
∗
br
br
c
d
Fig. 8.27a–d. Complete rupture of the distal biceps tendon. a Long-axis 12−5 MHz US image over the brachialis muscle (br)
shows hypoechoic fluid (asterisks) filling the distal bed of the retracted distal biceps tendon (dbt) and surrounding its myotendinous junction. In this particular case, the tendon edge (arrowheads) lies distal to the joint line. b−d Short-axis 12−5 MHz US
images obtained at the levels (vertical white bars) indicated in a demonstrate the torn and retracted tendon end (straight arrows)
surrounded by hypoechoic hematoma (asterisks). The relationships of the torn tendon with the brachial artery (arrowhead),
radial nerve (curved arrow), brachialis (br) and brachioradialis (brrad) muscles are shown
∗
∗
dbt
b
b
c
∗
a
c
Fig. 8.28a–c. Complete rupture of the distal biceps tendon. a Long-axis 12−5 MHz US image obtained proximal to the elbow joint
with b,c correlative transverse T2w SE MR images acquired at the levels (vertical white bars) indicated in a show the retracted
edge (arrows) of the distal biceps tendon (dbt) with hypoechoic fluid (asterisks) filling the gap
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S. Bianchi and C. Martinoli
dbt
dbt
br
br
∗
∗
br
br
b
a
∗
fpg
fpg
v
a
v
b
c
Fig. 8.29a–c. Acute complete rupture of the distal biceps tendon associated with a torn bicipital aponeurosis. a Long-axis
12−5 MHz US image over the brachialis muscle (br) demonstrates a markedly retracted tendon edge (dbt), the hematoma at the
rupture site (asterisks) and the absence of the tendon (arrows). b Short axis 12−5 MHz US image obtained at the level (vertical
white bar) indicated in a reveals fluid (arrowheads and curved arrow) in the soft tissues surrounding the flexor-pronator group
(fpg) of muscles, suggestive of a coincident injury of the lacertus fibrosus. In this case, the injury of the bicipital aponeurosis
was surgically confirmed. a, brachial artery; v, cubital veins. c Gross operative view of the same case
∗
a
b
∗
c
d
Fig. 8.30a–d. Partial rupture of the distal biceps tendon. a Long-axis and b short-axis 12−5 MHz US images obtained at level
distal to the elbow joint with c, d correlative transverse T1w SE MR images demonstrate a thickened and heterogeneous tendon
(arrows) inserting on the radial tuberosity (asterisk)
Elbow
a
Fig. 8.31a,b. Postoperative distal biceps tendon.
After surgical repair, a
long-axis and b shortaxis 12−5 MHz US images
reveal a thickened and
wavy distal biceps tendon
(arrows). Adhesions and
irregularities in the peritendinous tissues are also
seen. Observe the sutures,
which appear as bright
echoes
(arrowheads)
within the tendon substance
b
distal biceps tendon and the radial tuberosity to reduce
friction during pronation of the forearm (Skaf et al.
1999). Bicipitoradial bursitis is a rare condition that
may result from several causes (infection, inflammatory arthropathy, amyloidosis, etc.) but it is most commonly secondary to repetitive mechanical trauma as
well as to tendinosis and tearing of the distal biceps. On
clinical grounds, swelling of the bicipitoradial bursa
can be appreciated as a nonspecific mass in the antecubital fossa often associated with antecubital pain,
especially upon elbow motion and forearm rotation.
Because the clinical picture of bursitis is similar to
tendinitis and the deep location of the bursa makes
it difficult to palpate, a definite diagnosis of cubital
bursitis relies mainly on imaging findings.
When the bicipitoradial bursa is only mildly distended, US may have difficulty in distinguishing it
from the adjacent distal biceps tendon that appears
hypoechoic due to anisotropy (Miller and Adler
2000). Usually, transverse scans with the forearm supinated perform better in delineating the bursal shape.
At US, bicipitoradial bursitis appears as a hypoechoic
mass located in proximity to the distal biceps tendon
(Liessi et al. 1996). It may have septa, thick walls and
echogenic content. Rice bodies have been described
in this bursa with US (Spence et al. 1998). When distended by a large amount of fluid, the bicipitoradial
bursa can surround the distal portion of the distal
biceps tendon completely, thus mimicking a tenosynovitis (Fig. 8.32). Bicipitoradial bursitis must be
differentiated from synovial and ganglion cysts and
other soft-tissue masses. Ganglia commonly arise
from the anterior capsule and may expand at a variable distance from the joint, dissecting the soft tissues
of the forearm (Steiner et al. 1996). Visualization of
a pedicle that connects the cyst with the elbow joint
cavity may help the diagnosis. Calcified bursitis may
be encountered in patients with renal osteodystrophy
(Fig. 8.33). For asymptomatic bursitis no treatment
is necessary, whereas most symptomatic patients
are successfully treated with rest, physiotherapy and
anti-inflammatory drugs.
T
∗
a
T
T
∗
∗
∗
∗
b
Fig. 8.32a,b. Bicipitoradial bursitis. a Longitudinal and b transverse 12−5 MHz US images over the antecubital fossa at level distal
to the joint line show fluid distension of the bicipitoradial bursa (asterisks) which almost completely surrounds the adjacent
normal distal biceps tendon (T), thus mimicking a tenosynovitis process
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S. Bianchi and C. Martinoli
T
a
b
T
T
c
d
Fig. 8.33a–d. Calcified bicipitoradial bursitis in a woman with chronic renal failure who presented with a palpable mass in the
antecubital fossa and difficulties in pronation. a Photograph shows focal soft-tissue swelling (arrowheads) over the anterior
proximal forearm. b Transverse and c longitudinal 12−5 MHz US images reveal extensive hyperechoic deposits (arrows) with
faint posterior acoustic shadowing related to calcifications with the bicipitoradial bursa. The bursa exhibits thickened walls and
the distal portion of the biceps tendon (T) is completely surrounded by calcifications. d Correlative lateral radiograph shows
the bulk of calcifications (arrows) in the antecubital fossa
8.5.2
Medial Elbow Pathology
8.5.2.1
Medial Epicondylitis (Epitrochleitis)
Medial epicondylitis, commonly referred to as
“golfer’s elbow”, “medial tennis elbow” or “pitcher’s elbow”, occurs far less commonly than lateral
epicondylitis and usually presents with pain and
tenderness over the anterior aspect of the medial
epicondyle that is enhanced by grasping and by
resisted pronation of the forearm. Some sporting activities requiring repetitive valgus stress to
the elbow joint, such as golf, javelin throwing and
squash, may predispose to this condition. Medial
epicondylitis is produced by degeneration and
tearing of the common flexor tendon relative to
overuse of the flexor-pronator group of muscles.
Enthesopathy is frequently observed instead of
tendinopathy. In this condition, joint effusion is
absent and the elbow retains a full range of movements. The US appearance of medial epicondylitis
is similar to the appearance of the other degenerative tendinopathies that involve the attachment of
tendons to bone and includes hypoechoic changes
in the tendon substance secondary to tendinosis
or to partial-thickness tears (Fig. 8.34) (Ferrara
and Marcelis 1997). Complete tear of the common
flexor tendon is rare. In this clinical setting, US can
help to distinguish tendinopathy from a lesion of
the underlying medial collateral ligament. Ulnar
neuropathy may be associated with tendinosis of
the common flexor tendon.
Elbow
T
∗
∗
ME
a
ME
b
Fig. 8.34a,b. Medial epicondylitis. a Longitudinal and b transverse 12−5 MHz US images at the medial elbow in a golf player
with chronic elbow pain reveal a swollen common flexor tendon (arrowheads) with a full-thickness hypoechoic area (asterisk)
compatible with severe tendinosis. A normal-appearing medial collateral ligament (arrows) underlies the abnormal tendon
origin. ME, medial epicondyle; T, proximal portion of the common flexor tendon
8.5.2.2
Medial Collateral Ligament Injury
The medial collateral ligament is stronger than the
lateral collateral ligament. Its degeneration and tearing with or without an injury of the adjacent common
flexor tendon may be secondary to acute or chronically repeated overstretching in valgus stress during
the acceleration phases of throwing or may result
from a fall or from posterior dislocation of the elbow
(see Sect. 8.5.5.4). Baseball pitching is the sporting
activity most commonly associated with medial collateral ligament injuries and medial joint instability.
When the anterior band is injured, high-resolution
US reveals a thickened hypoechoic ligament with
surrounding effusion slightly posterior and deep
to the medial epicondyle (Vanderschueren et al.
1998; Jacobson and van Holsbeeck 1998; Ward et
al. 2003). Calcifications can also be associated with
ligamentous tears (Nazarian et al. 2003). In cases
of complete rupture, US examination may show
either a gap or focal hypoechoic areas in the proximal and distal portion of the ligament (Fig. 8.35)
(de Smet et al. 2002). To improve the diagnostic
confidence, high-frequency US examination can
provide dynamic assessment of the degree of medial
joint laxity in both neutral and valgus stressed positions (de Smet et al. 2002). In a series of asymptomatic baseball pitchers, the medial elbow joint space
of the throwing arm was significantly wider during
valgus stressing than the joint space in the elbow
of the nonthrowing arm (Nazarian et al. 2003). In
symptomatic patients, widening of the trochlea-ulna
joint and soft tissue falling into the distracted joint
space suggest a medial collateral ligament injury
(de Smet et al. 2002). Dynamic US scanning may
be particularly useful in the event of partial-thickness tears, in which the ligament is continuous but
lax (Fig. 8.9). Examination of the noninjured elbow
should be obtained to compare the amount of joint
widening that occurs during valgus stressing.
8.5.2.3
Epitrochlear Lymphadenopathies
Just proximal to the elbow and adjacent to the medial
epicondyle and the medial neurovascular bundle,
small lymph nodes may enlarge as a result of reactive
or septic inflammation (Barr and Kirks 1993). One
of the leading causes of medial epitrochlear regional
fm
fm
∗
ME
Ulna
Ulna
Fig. 8.35. Medial collateral ligament injury. Longitudinal
12−5 MHz US image obtained with valgus stress over the anterior band of the medial collateral ligament (arrowheads) shows
a focal hypoechoic area in the proximal ligament and mild widening of the elbow joint (arrows) compatible with a ligamentous
injury. ME, medial epicondyle; fm, flexor muscles
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lymphadenopathy is “cat-scratch” disease, an infection caused by a gram-negative bacterium, Bartonella henselae, usually transmitted by scratches of the
hand by an animal (most patients have a history of
exposure to a cat!). However, enlarged lymph nodes
in the epitrochlear area may also be involved by
other disorders, including benign and malignant
forms. US reveals the appearance of reactive lymph
nodes consisting of oval hypoechoic masses with an
echogenic hilum, often hypervascular at color Doppler imaging (Fig. 8.36). This appearance is typical
and works well to rule out other soft-tissue masses,
such as neurogenic tumors or sarcomas. The US
examination should be extended up to the axillary
region in order to rule out the possible coexistence
of axillary lymphadenopathies. In cat-scratch disease, lymphadenopathies may be multiple and contiguous. Clinically, they are accompanied by painful
soft-tissue swelling and systemic symptoms, such
as fever and malaise. The involved nodes have a
hypervascular pattern at color and power Doppler
imaging and tend to develop central necrosis and
liquefaction (Carcía et al. 2000; Gielen et al. 2003).
Hyperechoic infiltration of the perinodal fat due
to cellulitis is a characteristic finding (Fig. 8.37a).
Enlarged lymph nodes most often regress over
weeks to months. Whatever the cause of epitrochlear
lymphadenopathies, US may exclude a local softtissue mass, thus obviating the need for biopsy or
resection of this pseudotumor (Gielen et al. 2003).
With time from the acute process, and especially in
the elderly, the reactive nodes may undergo diffuse,
massive adipose infiltration leading to a broad and
hyperechoic medulla and progressive atrophy of the
outer cortex (Fig. 8.37b). In these cases, the examiner should be careful not to mistake these atrophic
nodes for lipomas or other hyperechoic soft-tissue
masses. Detection of a thin continuous hypoechoic
rim related to the atrophic cortex of the node may
help the diagnosis (Fig. 8.37b).
8.5.3
Lateral Elbow Pathology
8.5.3.1
Lateral Epicondylitis
The most common disorder involving the lateral
elbow is lateral epicondylitis, also known as “tennis
elbow”, caused by repetitive traction on the osteotendinous attachment of the common extensor tendon
(Regan et al. 1992). This condition can be the result of
a
b
c
Fig. 8.36a–c. Epitrochlear lymphadenopathy. a Long-axis and
b short-axis 12−5 MHz US images over the medial elbow in
a patient with a painful palpable mass associated with the
medial epicondyle. US identifies an oval hypoechoic mass
with echogenic hilum consistent with a superficial lymph node
(arrowheads). c Color Doppler imaging reveals a hypervascular pattern of the node with a vessel pedicle (arrow) that enters
the hilum and branches through the hypoechoic cortex. This
lymph node regressed 2 weeks after medical treatment
chronic microtrauma secondary to repetitive overuse
related to professional or recreational activities leading to progressive degeneration and/or partial tears
of the common extensor tendon (tendinopathy) or
to damage to the bone insertion (enthesopathy). The
extensor carpi radialis brevis is the more commonly
affected component of the common extensor tendon.
Although lateral epicondylitis typically occurs in
tennis players who injure this tendon–especially
during the backhand stroke, in which the extensors
Elbow
a
b
Fig. 8.37a,b. Epitrochlear lymphadenopathies in two different individuals with a active cat-scratch disease and b without any
signs of infectious or inflammatory abnormalities. In a, the inflamed node is completely hypoechoic (arrowheads) with loss of
definition of the echogenic hilum and appears surrounded by abnormally hyperechoic fat (arrows) due to perinodal cellulitis.
In b, massive adipose infiltration has occurred in an epitrochlear lymph node (arrowheads) leading to a broad hyperechoic
medulla. The cortical portion is markedly reduced in thickness and appears as a thin peripheral hypoechoic rim (arrows)
are subjected to a greater tensioning–this condition is
seen far more commonly in nonathletes. In tendinopathy, patients report a localized pain over the common
extensor tendon during or just after repetitive muscle
activation, whereas in enthesopathy, pain is confined
to the tendon’s insertional area. Physical examination
reveals localized tenderness over the lateral aspect of
the elbow radiating down to the proximal forearm or
well localized over the lateral aspect of the epicondyle
respectively. Intra-articular effusion is not an associated finding. In chronic longstanding disease, pain at
rest and limitation in joint extension can be noted.
The diagnosis is usually based on clinical findings and does not require imaging studies. US may be
useful to confirm the clinical diagnosis in doubtful
or refractory cases, to reveal the extent and severity
of the disease and to monitor the response to therapy.
The main US features of lateral epicondylitis are preinsertional hypoechoic swelling of the tendon with
focal or diffuse areas of decreased reflectivity in the
tendon substance and loss of the fibrillary pattern
related to tendinosis, fluid adjacent to the common
tendon and ill-defined tendon margins (Figs. 8.38,
8.39) (Maffulli et al. 1990; Connell et al. 2001;
Miller et al. 2002d; Levin et al. 2005). In a recent
series, the mean size of the focal hypoechoic areas
was 8.7 mm (range 3–15 mm) (Connell et al. 2001).
Although early tendon abnormalities may be confined
to the superficial fibers (Fig. 8.38a,b), involvement of
the deep fibers of the extensor carpi radialis brevis
component is more common and may even extend
down to the joint capsule (Fig. 8.38c,d). Similarly, the
anterolateral and mid-portion of the common extensor
tendon is more commonly involved, whereas the posterior portion usually remains unaffected (Fig. 8.38b)
(Connell et al. 2001). In high-grade tendinosis, the
angiofibroblastic infiltration based on migration of
fibroblasts and vascular granulation tissue within
the tendon substance causes a striking hypervascular pattern of the intratendinous hypoechoic areas
at color and power Doppler imaging (Fig. 8.39b).
Spurring at the common extensor tendon insertion
and cortical irregularities at the anterolateral surface of the lateral epicondyle may also be recognized,
although bony changes do not correlate with disease
activity. Intratendinous calcifications may also be
seen as part of crystal deposition diseases (Fig. 8.40).
In partial tears, the common extensor tendon may
appear thinned compared with the opposite side. In
practice, discrimination of focal areas of tendinosis
and partial tears can be difficult and US is reliable for
recognizing a partial tear only when discrete anechoic
cleavage planes with no fibers intact are visible in the
tendon substance (Connell et al. 2001). These tears
typically appear as longitudinal splits oriented from
the bony insertion distally (Fig. 8.41). Thickening of
peritendinous soft tissues and a thin layer of superficial fluid over the extensor tendon are also more often
observed with partial tears. In complete tears, US identifies a fluid-filled gap separating the tendon from its
bony attachment site (Fig. 8.42) (Jacobson and van
Holsbeeck 1998; Connell et al. 2001). Overall, US
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∗
∗
RH
∗
∗
LE
LE
a
b
RH
∗
∗
∗
∗
LE
c
LE
d
Fig. 8.38a–d. Lateral epicondylitis: spectrum of US appearances in a weightlifter with bilateral lateral elbow pain. a Long-axis
and b short-axis 12−5 MHz US images over the right common extensor tendon origin reveal a hypoechoic focus (asterisks)
of tendinosis in the superficial fibers of an otherwise normal-appearing tendon (arrowheads). c Long-axis and d short-axis
12−5 MHz US images over the left common extensor tendon origin demonstrate a large hypoechoic area (asterisks) affecting
both superficial and deep fibers of the tendon (arrowheads), indicating severe tendinopathy. On cross-section, the abnormal
hypoechoic areas with loss of fibrillary echotexture (asterisks) are seen involving the full thickness of the anterior half of the
tendon (arrowheads). In both elbows, observe the integrity of the deepest fibers in relation to the lateral collateral ligament.
LE, lateral epicondyle; RH, radial head
has proved to be as specific but not as sensitive as MR
imaging for evaluating epicondylitis (Miller et al.
2002). On the other hand, US of the common extensor
tendon has high sensitivity but low specificity in the
detection of symptomatic cases (Levin et al. 2005).
Conservative treatment with rest, anti-inflammatory drugs, physiotherapy and local steroid injections gives satisfactory results in most cases of lateral
epicondylitis. Surgical intervention with excision of
the degenerated tissue, resection of the common
extensor tendon and debridement of the extensor
tendon origin with release of the annular ligament
may be advocated in refractory cases. Confirmation of the disease and exclusion of other causes of
lateral elbow pain which may mimic or accompany
lateral epicondylitis, such as posterior interosseous
nerve entrapment or lateral collateral ligament inju-
ries, should, however, be ascertained with imaging
modalities, and possibly with US, before submitting
the patient to surgery.
8.5.3.2
Lateral Collateral Ligament Injury
In lateral epicondylitis, the lateral elbow ligamentous
complex, and especially the lateral ulnar collateral
ligament, should be routinely assessed because this
ligament is commonly injured in association with
tears of the common extensor tendon as a result of
the same forces or overuse mechanisms on adjacent
structures (Bredella et al. 1999). An unsuspected
tear of this ligament may be the cause of conservative therapy failure in patient with lateral epicon-
Elbow
∗
∗
RH
LE
a
2(
,%
b
Fig. 8.39a,b. Lateral epicondylitis in a professional tennis player with a history of chronic right lateral elbow pain. a Long-axis
gray-scale 12−5 MHz US image reveals a hypoechoic focus (asterisks) in the most superficial fibers of the common extensor
tendon origin (arrowheads), whereas the deep fibers are preserved. b Color Doppler imaging demonstrates a striking hypervascular pattern composed of series of tiny vessels throughout the intratendinous hypoechoic areas, characteristic of tendinosis.
LE, lateral epicondyle; RH, radial head
RH
a
LE
b
Fig. 8.40a,b. Calcifying lateral epicondylitis. a Long-axis 12−5 MHz US image with b radiographic correlation in a patient with
calcium pyrophosphate crystals deposition disease and recent onset of lateral elbow pain demonstrates large calcified foci (arrows)
within the common extensor tendon origin. LE, lateral epicondyle; RH, radial head
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S. Bianchi and C. Martinoli
∗
✟
★
∗
∗
RH
LE
Fig. 8.41. Partial-thickness tear of the common extensor tendon. Long-axis 12−5 MHz US image in a manual laborer who presented with acute onset of lateral elbow pain reveals a linear hypoechoic split (star) extending from the lateral epicondyle (LE)
through the substance of the common extensor tendon origin. The torn deep fibers (arrowheads) are retracted just distal to the
hypoechoic area. Note the integrity of the underlying lateral ulnar collateral ligament (asterisks). RH, radial head
∗
LE
RH
a
LE
LE
∗
∗
RH
RH
b
c
Fig. 8.42a–c. Complete rupture of the
common extensor tendon. a Long-axis
12−5 MHz US image in a golfer player
who complained of longstanding elbow
pain with coronal b T1w SE and c fatsuppressed T2w SE MR imaging correlation shows a retracted common extensor tendon. Note the gap (arrowheads)
related to the tear that separates the
avulsed tendon edge (asterisk) from the
lateral epicondyle (LE). RH, radial head
Elbow
dylitis. In addition, when the torn lateral ulnar collateral ligament is not recognized preoperatively, the
operative release of the common extensor tendon
may be responsible for worsening of symptoms and
onset of posterolateral rotatory instability of the
elbow (see Sect. 8.5.5.4).
When the more superficial extensor carpi radialis brevis is torn, the deep lateral ulnar collateral
ligament becomes more clearly distinguishable
with US as a cord-like fibrillary structure located
over the joint space (Fig. 8.41). An isolated ligament tear appears as discontinuity of the deepest fibers of the extensor tendon origin, whereas
tears involving both the ligament and the common
extensor tendon cause a full-thickness interruption of fibers over the lateral aspect of the radiocapitellar joint and soft tissue hematoma around
the proximal margin of the capitellum (Connell
et al. 2001). Dynamic scanning during careful
varus stressing can disclose lateral ulnar collateral
ligament injury by depicting widening of the lateral elbow joint space compared with the opposite
normal elbow (Fig. 8.43).
In “pulled elbow”, a common injury among children due to slipping of the annular ligament over the
radial head following forceful pronation, US is able
to depict an increased distance between the radial
head and the humeral capitellum probably due to the
impingement of the annular ligament (Kosuwon et
al. 1993) - see also chapter 19.
8.5.3.3
Supinator Syndrome
(Posterior Interosseous Neuropathy)
Supinator syndrome, also referred to as “posterior
interosseous syndrome” or “radial tunnel syndrome”,
is a rare compression neuropathy of the upper limb
affecting the posterior interosseous nerve just near
or behind the supinator muscle (Spinner 1968). This
nerve is vulnerable to injury at the proximal edge
of the superficial belly of the supinator muscle that
forms a free, strong, fibrous arch, the “arcade of
Frohse”. At this site, the posterior interosseous nerve
may be tethered and entrapped by fibrous bands,
∗
∗
RH
LE
a
c
∗
RH
b
∗
LE
Fig. 8.43a–c. Complete tear of the common extensor tendon
and the lateral ulnar collateral ligament. a, b Longitudinal
12−5 MHz US images obtained over the common extensor
tendon origin a in neutral position and b with varus stressing. In a, US identifies a large horizontal hypoechoic cleft
through the full thickness of the common extensor tendon
origin (arrows) and the lateral ulnar collateral ligament (asterisks). In b, varus stress on the elbow shows widening of the
radio-capitellar joint space (dashed lines). RH, radial head; LE,
lateral epicondyle. c Correlative STIR MR image confirms the
complete rupture of both structures (arrowheads)
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fan-shaped recurrent radial vessels or by tightness
of the passage within the superficial and deep layers
of the supinator. In addition, it may be compressed
by a variety of soft-tissue masses, such as paraosteal
lipomas and deep ganglia. Radial head and neck
fractures, including Monteggia fracture-dislocations, may also displace and encase the posterior
interosseous nerve by callus as it passes through the
supinator tunnel. Clinically, the posterior interosseous neuropathy produces a clinical picture distinct from a lesion of the radial nerve in the arm. In
fact, the patient has a “finger drop” rather than the
characteristic “wrist drop” of a radial neuropathy,
because muscle weakness spares the extensor carpi
radialis (Fig. 8.44). Extension of the fingers at the
metacarpophalangeal joints is impaired and there
is deficit of abduction and extension of the thumb.
In addition, posterior interosseous neuropathy may
cause burning pain and tenderness over the lateral
elbow, possibly mimicking a “resistant lateral epicondylitis”.
High-resolution US is able to identify the impingement of the posterior interosseous nerve in the supinator area. The compressed nerve typically appears
swollen and hypoechoic proximal to or inside the
supinator muscle (Bodner et al. 2002). In post-traumatic settings, the nerve may appear displaced by
a malaligned radial head and may exhibit alternate
thickened and thinned segments between the superficial and deep bellies of the supinator muscle as a
possible result of stretching injury (Fig. 8.45). In addition, the nerve may be seen encased by hypoechoic
scar tissue following a radial fracture (Fig. 8.46).
Decompressive surgery of the posterior interosseous nerve is indicated if there is continuous worsening or no recovery of function with a few months.
8.5.4
Posterior Elbow Pathology
8.5.4.1
Distal Triceps Tendon Tear
Distal triceps tendon tear is an uncommon condition that mostly occurs at or close to the olecranon
process of the ulna, often associated with a fleck
of bone attached to the retracted tendon as a result
of avulsion fracture (Fig. 8.47). The mechanism
involves either forced flexion of the elbow against
a contracting triceps, as occurs during a fall on an
outstretched arm, or relates to a direct blow onto
the olecranon process. Local steroid injection into
the olecranon bursa, anabolic steroid abuse and
pre-existing tendinosis may also have a role in the
tendon rupture. As a rule, complete tears occur more
U
epl
R
c
U
a
b
d
epb
epl
epb
R
Fig. 8.44a–d. Posterior interosseous nerve syndrome in a young woman who presented with a intense weakness in extending the
right fingers, especially involving thumb movements, and b a longitudinal skin depression (arrow) over the dorsum of the forearm
following a contusion to the lateral elbow. c Transverse 12−5 MHz US image at the middle dorsal forearm reveals loss in bulk and
a hyperechoic appearance of the extensor pollicis longus (epl) and extensor pollicis brevis (epb) muscles relative to fatty atrophy.
Surgery confirmed the traumatic injury of the posterior interosseous nerve. d Normal contralateral side. U, ulna; R, radius
Elbow
s
s
s
s
s
s
Radius
a
s
s
R
R
s
s
b
R
c
s
d
e
Fig. 8.45a–e. Posterior interosseous nerve syndrome in a patient with malaligned Monteggia fracture-dislocation (type IV).
a Extended field-of-view 12−5 MHz US image reconstructed according to the longitudinal axis of the supinator tunnel demonstrates the posterior interosseous nerve (arrowheads) which alternates thickened and thinned portions as it traverses the
supinator muscle (s). b–d Serial T2*GRE MR images reveal slight hyperintensity in the supinator muscle (s) due to denervation
edema. The nerve (arrows) appears markedly hyperintense. R, radius. e Radiograph shows the malalignment of the radius, which
appears subluxated anterolaterally
s
s
a
b
Radius
Fig. 8.46a,b. Posterior interosseous nerve syndrome.
a Transverse 12−5 MHz US image obtained over the supinator
area in patient with a previous radial head fracture and radial
nerve deficit demonstrates the posterior interosseous nerve
(arrowheads) entrapped within a hypoechoic scar (arrows) in
the area of the supinator muscle (s). b Gross operative view
shows the main trunk of the radial nerve (asterisks) as it splits
into the superficial cutaneous sensory branch (arrowheads)
and the deep posterior interosseous nerve (narrow arrows).
This latter nerve is irregularly swollen as it passes over the bone
(large arrows) as a result of the scar encasement visible in a
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1
1
∗
2
∗
2
a
b
c
Fig. 8.47a–c. Avulsion fracture of the olecranon in a boy following a bicycle accident. a Reconstructed midsagittal 12−5 MHz
US image over the posterior elbow with b lateral radiographic correlation demonstrates the avulsion fracture of the olecranon
process (1) from the ulnar shaft (2) due to a traction mechanism by the distal triceps tendon (arrows). Note the coexisting avulsion of the cartilaginous growth plate (asterisks). c Lateral radiograph of the opposite healthy side shows incomplete ossification
(curved arrow) between the olecranon and the ulnar shaft
frequently than partial tears, whereas disruption of
either the muscle bellies or the myotendinous junction is rare. Complete rupture of the distal triceps
tendon presents clinically with complete inability to
extend the elbow, given the absence of other muscles
that can assist in this movement. In the acute phase,
however, the clinical diagnosis may be hampered by
local soft-tissue swelling, inflammatory edema and
pain that limit the physical examination. In such
cases, US may be useful both to confirm the tendon
injury and to differentiate between complete tears
that require immediate surgery to avoid retraction
of the tendon and partial tears that may be treated
conservatively. In acute complete ruptures, US demonstrates the distal triceps tendon as wavy, retracted
and surrounded by fluid (Fig. 8.48) (Kaempffe and
Lerner 1996). US examination is also reliable to
delineate the degree of tendon retraction and can
help in the diagnosis of atypical ruptures, such as in
cases of tears occurring at the myotendinous junction (Fig. 8.49). Due to the close anatomic relation of
the distal triceps tendon with the medial epicondyle
and the cubital tunnel, an acute ulnar nerve compression syndrome may occur secondary to a distal
triceps tendon tear (Duchow et al. 2000). Degenerative tendinosis can be appreciated as a thickened
hypoechoic tendon.
8.5.4.2
Olecranon Bursitis
Olecranon bursitis, the most common superficial
bursitis in the body, appears clinically as a lump
overlying the olecranon process due to fluid distension or hypertrophy of the synovial membrane.
The most common cause of olecranon bursitis is
repetitive local contusion (student’s elbow, miner’s
elbow) that leads to a painless local swelling covered
by normal skin. Calcific enthesopathy of the distal
triceps tendon is a predisposing factor. However,
bursal distension can be appreciated in a variety
of systemic disorders, such as rheumatoid arthritis,
gout, hydroxyapatite and calcium pyrophosphate
deposition diseases, as well as in septic conditions
(e.g. Staphylococcus, tuberculosis); also patients
under chronic hemodialysis treatment may occasionally have olecranon bursitis. When bursitis is
secondary to infection or gout, bursal swelling is
typically painful and associated with skin warmth
and erythema due to local inflammatory changes.
Because systemic findings are often absent in septic
bursitis, the likelihood of an infected bursa must
always be kept in mind. Similarly, when the patient
has a history of tuberculous disease, a specific etiology of bursitis should first be suspected.
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∗
∗
O
∗
∗
a
b
c
Fig. 8.50a–c. Chronic traumatic olecranon bursitis in a manual laborer who had recently injured several times his posterior
right elbow. a Midsagittal and b transverse 12−5 MHz US images over the olecranon process (O) show a markedly distended
olecranon bursa (arrowheads) containing thick septa (curved arrows) and anechoic effusion (asterisks). Straight arrows, distal
triceps tendon. c Photograph showing the bursal lump (arrows) on the posterior elbow
∗
∗
∗
O
a
★
∗
b
∗
∗
O
O
c
following bursal rupture. In such patients, subcutaneous nodules can be seen in the olecranon region
and along the proximal ulna. These nodules should
be considered in the differential diagnosis as they can
mimic olecranon bursitis or a solid neoplasm Distal
∗
Fig. 8.51a–c. Hydroxyapatite olecranon
bursitis. a Transverse and b,c longitudinal
12−5 MHz US images of a painful softtissue mass over the olecranon (O) show
the olecranon bursa filled with homogeneous highly echogenic fluid (asterisks)
that could be seen fluctuating during probe
compression. The bursa exhibits thickened
walls (arrowheads) and septa (arrows). In
this case, needle aspiration of the bursal
fluid revealed calcium milk solution
to the olecranon bursa, an additional small subolecranon bursa can exist at the posterior aspect of the
proximal ulnar shaft. In rare instances, this bursa
can be involved by the same processes affecting the
larger olecranon one (Fig. 8.54).
Elbow
∗
∗
O
a
b
Fig. 8.52a,b. Tuberculous olecranon bursitis. a Longitudinal gray-scale and b color Doppler 12−5 MHz US images in a patient
with painful soft-tissue swelling over the posterior elbow. The olecranon bursa (arrowheads) shows irregular wall thickening
and ill-defined margins due to coexisting peribursal cellulitis. Only a small amount of intrabursal fluid is seen (asterisks). dt,
distal triceps tendon; O, olecranon
∗
∗
∗
H
∗
★
a
b
Fig. 8.53a,b. Calcific olecranon bursitis in a patient with renal osteodystrophy. a Posterior midsagittal 12−5 MHz US image with
b lateral radiographic correlation demonstrates a large calcification (asterisks) that lies superficial to the insertion of the distal
triceps tendon (arrowheads) reflecting an extensively calcified bursa. Note the relation of the mass with the posterior olecranon
fossa (star) and the humeral shaft (H)
a
b
Fig. 8.54a,b. Subolecranon bursitis nodule in a patient with severe rheumatoid arthritis. a Transverse 12−5 MHz US image
reveals a painless heterogeneous soft-tissue mass (arrows) with mixed echotexture located in the subcutaneous tissue over the
proximal posterior ulna, compatible with subolecranon bursitis. b Photograph of the same case shown in a
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8.5.4.3
Cubital Tunnel Syndrome
Ulnar nerve compression inside the cubital tunnel,
the second most common entrapment syndrome of
the upper limb after carpal tunnel syndrome, may
occur either at the condylar groove or at the edge of
the arcuate ligament (proper cubital tunnel). There
are several causes of ulnar nerve damage, including
direct extrinsic compression of the nerve against a
shallow condylar groove, bone abnormalities (cubitus valgus, deformities from previous elbow fractures, osteoarthritis with medial osteophytes and
loose bodies, heterotopic ossification) and a variety
of space-occupying soft-tissue lesions, including
thickening of the capsule and the medial collateral
ligament, ganglia and accessory muscles (anconeus
epitrochlearis muscle) (Stewart 1993). Clinically,
the entrapment of the ulnar nerve at the elbow presents insidiously with medial elbow pain and a spectrum of complaints ranging from sensory symptoms
in the ring and little fingers to weakness of the ulnarinnervated hand muscles. Wasting of hand muscles
is best appreciated at the first interosseous space and
hypothenar eminence and causes a typical semiflexion deformity of the ring and little fingers that is
commonly referred to as “claw hand” (Fig. 8.55). In
addition, the little finger may stay slightly abducted
(Wartenberg sign).
The diagnosis is essentially based on electrophysiologic studies. US typically demonstrates an abrupt
narrowing and displacement of the nerve within the
tunnel, possibly in association with a thickened retinaculum or a space-occupying lesion (Fig. 8.56) (Puig
et al. 1999; Martinoli et al. 2000; Okamoto et al.
2000). Proximal to it, the compressed nerve appears
swollen with loss of the fascicular pattern and, in some
cases, hypervascularity at color Doppler imaging. As
assessed by quantitative analysis with US, the nerve
cross-sectional area at the epicondyle is significantly
larger in patients with cubital tunnel syndrome than
in healthy subjects or in the opposite normal elbow
(Okamoto et al. 2000; Chiou et al. 1998). An ulnar
nerve area ≥7.5 mm2 at the level of the epicondyle
has been indicated as the threshold value for cubital
tunnel syndrome (Chiou et al. 1998). These data are
somewhat contradictory with a more recent paper
which indicates 7.9mm2 as the mean cross-sectional
area for the normal ulnar nerve at the elbow (Jacob
et al. 2004). Besides assessing the ulnar nerve, a wide
spectrum of extrinsic causes for nerve entrapment
may be recognized with US as well, including congenital anomalies such as an accessory anconeus epitrochlearis muscle (Fig. 8.57), and acquired disease which
IV
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II
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c
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a
II
b
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III
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IV
d
Fig. 8.55a–d. Claw-like deformity in the right hand of a young patient with severe ulnar neuropathy at the cubital tunnel level.
a Photograph of the dorsal aspect of the hand reveals loss in bulk of the dorsal interosseous muscles (arrows) that lie in the
intermetacarpal spaces. The atrophy of the ulnar-innervated hand muscles is more obvious at the first intermetacarpal space
(asterisk). b Photograph of the palmar aspect of the hand shows the fourth and fifth fingers extended at the metacarpophalangeal
joint and flexed at the interphalangeal joints. c Transverse 12−5 MHz US image at the dorsal aspect of the hand demonstrates
a hyperechoic appearance of the dorsal interosseous muscles (asterisks) related to neurogenic fatty atrophy. d Contralateral
healthy side. II–III–IV, metacarpals
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a
ME
O
b
c
ME
O
L
L
d
e
in turn leads to an increased content–i.e., lipoma
(Fig. 8.58)–or a decreased size–i.e. fracture residuals
(Fig. 8.59)–of the tunnel.
Surgical decompression of the ulnar nerve at the
elbow may include slitting the Osborne fascia and
the aponeurosis of the flexor carpi ulnaris leaving
the nerve inside the cubital tunnel. Alternatively,
the nerve may be transposed out of the condylar groove and the cubital tunnel, anterior to the
medial epicondyle and superficial to the flexor
muscles (Fig. 8.60). This surgical option is preferred
in cases of ulnar neuropathies caused by bone and
joint disease. After surgical transposition, persistent symptoms are usually related to an excessive
angling of the ulnar nerve as it passes deep to the
arcuate ligament or to incomplete stabilization of
the nerve in its new position. US is able to identify
scar tissue along the course of the nerve in patients
with recurrent symptoms or relapse of compressive
causes (Fig. 8.61).
Fig. 8.58a–e. Cubital tunnel syndrome
in a patient presenting with a superficial soft-tissue mass on the posteromedial elbow. a Reconstructed longitudinal
and b transverse 12−5 MHz US images
obtained just proximal to the cubital
tunnel demonstrate the ulnar nerve
(curved arrow) that shows a bowing
course over an oval solid hyperechoic
lesion (arrowheads) with well-defined
margins, consistent with a lipoma. Note
the close relationship of the mass with
the nerve. c Transverse 12−5 MHz US
image obtained at the cubital tunnel
level shows the lipoma (arrowheads)
that infolds within the tunnel leading to compression of the ulnar nerve
(curved arrow). ME, medial epicondyle;
O, olecranon. d,e Correlative transverse
T1w SE MR images obtained d at the
distal arm and e at the cubital tunnel
levels confirm the lipomatous nature of
the space-occupying lesion (L). Curved
arrow, ulnar nerve; ME, medial epicondyle; O, olecranon
8.5.4.4
Ulnar Nerve Instability
In the congenital partial or complete absence of the
cubital tunnel retinaculum, the ulnar nerve may
subluxate over the tip of the epicondyle or dislocate anterior to it with a transient snapping sensation during flexion of the elbow, to return inside
the tunnel when the joint is extended. Ulnar nerve
instability at the cubital tunnel can be considered a
normal variant, being reported in between 16% and
47% of asymptomatic healthy people, subluxation
being the most common form (Childress 1975;
Okamoto et al. 2000). The condition is bilateral in
almost three quarters of cases and asymptomatic
at both clinical examination and nerve conduction
studies. Patients may occasionally complain of only
mild discomfort with tingling and paresthesias
when the flexed elbow hits a firm surface such as the
edge of a desk. In rare instances, however, chronic
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b
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c
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d
microtrauma of the nerve over the medial epicondyle due to repetitive dislocation can cause friction
neuritis with symptoms and signs of ulnar nerve
impairment. In such cases, nerve instability should
be treated with surgical transposition of the nerve
in order to avoid more serious damage.
Dynamic US scanning is an ideal means to depict
the instability of the ulnar nerve during progressive
elbow flexion, to recognize nerve abnormalities related
to friction neuritis as well as to establish whether
ulnar neuropathy is produced by compressive causes
or instability because of the overlap in clinical findings (Jacobson and van Holsbeeck 1998; Jacobson
et al. 2001). In subluxation, the nerve is seen moving
over the apex of the medial epicondyle during full
active elbow flexion but no further. In dislocation,
the nerve may be seen snapping completely out of the
cubital tunnel and migrating over the common flexor
tendon origin (Fig. 8.62). During dynamic scanning,
the snapping sensation may be felt by the examiner
through the transducer. Careful scanning technique
is needed to avoid excessive pressure with the probe
over the epicondyle, which can prevent the nerve
Fig. 8.61a–d. Postoperative patient with
recurrence of symptoms after decompressive surgery of the ulnar nerve at
the cubital tunnel for a ganglion cyst.
a,b Transverse 12−5 MHz US images
obtained a at the cubital tunnel level
and b at the proximal forearm with
c,d T1w SE MR imaging correlation
show a relapsed cyst (asterisks) which
constricts the transposed ulnar nerve
(arrow). The patient underwent surgery
again and the postoperative course was
finally uneventful. ME, medial epicondyle
from dislocating. In cases of symptomatic friction
neuritis, the ulnar nerve appears markedly swollen
and hypoechoic with loss of fascicular echotexture,
probably reflecting localized intraneural edema and
fibrotic changes (Fig. 8.63). However, these abnormalities may occasionally be encountered in healthy
subjects too, without any implication of disease.
8.5.4.5
Snapping Triceps Syndrome
With elbow flexion, anterior dislocation of the medial
head of triceps muscle relative to the medial epicondyle can occur in combination with dislocation of the
ulnar nerve. In this condition, referred to as “snapping triceps syndrome”, the dislocation of the muscle
leads to concurrent dislocation of the adjacent ulnar
nerve as these structures are contiguous (Fig. 8.64).
Two palpable “snaps” are typically appreciated over
the medial elbow, the first one reflecting dislocation
of the ulnar nerve and the second, dislocation of the
medial head of triceps muscle. The clinical presen-
Elbow
ME
a
d
ME
b
e
ME
c
f
ME
ME
a
b
ME
ME
c
Fig. 8.62a–f. Dynamic study of the
cubital tunnel in ulnar nerve dislocation. a–c Schematic drawings and
d–f respective series of transverse
12−5 MHz US images obtained a,d
with extended elbow and during
progressive degrees of elbow flexion (b,e and c,f). When the elbow is
extended, the ulnar nerve (arrow) is
contained within the tunnel. Elbow
flexion gradually pushes the nerve
over the medial epicondyle (ME)
until it snaps completely out of the
cubital tunnel to lie superficial to
the common flexor tendon origin
(ft). O, olecranon
d
Fig. 8.63a–d. Dynamic study of
the cubital tunnel in a patient with
recurrent ulnar nerve dislocation
and clinical symptoms of ulnar
neuropathy. a–d Series of transverse
13−8 MHz US images acquired
a with extended elbow and b–d
throughout elbow flexion show a
markedly swollen and hypoechoic
nerve (arrow) that flattens and dislocates over the medial epicondyle
(ME) during elbow flexion. In the
symptomatic patient, this finding
is suggestive of ulnar neuropathy
based on a friction mechanism
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a
b
tation of this syndrome is variable and may include
medial elbow pain, snapping sensation, ulnar neuropathy or a combination of these szymptoms (Spinner and Goldner 1998). Somewhat similar to the
isolated dislocation of the ulnar nerve, the snapping
triceps may however remain asymptomatic and
probably unrecognized in most cases. Although the
cause of snapping triceps is still unknown, some possible congenital and acquired conditions have been
advocated to explain this syndrome, such as a hypertrophied triceps muscle, an accessory triceps tendon
and abnormal medial head of the triceps muscle, as
well as post-traumatic osseous abnormalities. Differentiation between snapping triceps syndrome and
isolated ulnar nerve dislocation as causes for medial
elbow snapping is important in symptomatic subjects as the surgical treatments differ. For this purpose, dynamic US scanning is accurate in allowing
direct visualization of transient dislocation of both
structures during active flexion and extension of the
elbow (Fig. 8.65) (Jacobson et al. 2001).
8.5.5
Bone and Joint Disorders
8.5.5.1
Synovitis
A variety of inflammatory diseases can affect the
elbow. The main pathologic findings are joint effusion, synovial hypertrophy and destructive bone
Fig. 8.64a,b. Snapping triceps syndrome. Schematic drawings of the posterior aspect of the elbow in a extension and b
90° flexion demonstrate the ulnar nerve (arrows) as it passes
through the cubital tunnel and a prominent medial head (mh)
of the triceps muscle (tm). Note the absence of the Osborne
retinaculum when compared with Fig. 8.7c. With elbow flexion, the medial edge of the triceps (arrowheads) and the ulnar
nerve move anterior to the tip of the epicondyle. T, distal triceps tendon; fcu, flexor carpi ulnaris
abnormalities. Physical examination reveals a swollen
joint with local inflammatory changes and a reduced
range of movements. Incomplete elbow extension can
be due either to increased intra-articular fluid or to
destructive changes of the articular surfaces. Clinically, joint effusion can be palpated as a localized
swelling and tenderness over the anterolateral aspect
of the joint, at the level of the radio-capitellar joint,
or posteriorly at both sides of the triceps tendon. The
accumulation of joint fluid can be reliably recognized
with US by examining the distended recesses of the
elbow joint, including the larger coronoid fossa and
the smaller radial fossa anteriorly and the olecranon
fossa posteriorly (Fig. 8.66) (DeMaeseneer et al.
1998). Small amounts of fluid initially collect in the
olecranon recess and are best revealed with US while
keeping the elbow flexed. In fact, the interposition of
the olecranon in elbow extension may make visualization of a small amount of joint fluid more difficult in
this recess (DeMaeseneer et al. 1998). With increasing quantities, synovial processes cause progressive
elevation of the anterior and posterior fat pads giving
them a crescent-shaped appearance of them (Figs. 8.67,
8.68) (Koski 1990; DeMaeseneer et al. 1998). With
the elbow extended, the anterior fat pad is pushed by
the brachialis against the bone and less fluid tends
to collect in the coronoid and radial fossae compared with when the elbow is flexed (DeMaeseneer
et al. 1998). The recesses located inferiorly to the
anterior fat pad, including the annular one, fill with
fluid only in cases with large amounts of joint effusion (Fig. 8.69). In the case of small effusions, and
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∗
HC
∗
RH
a
HC
c
∗
∗
∗
HC
∗
HC
b
d
Fig. 8.67a–d. Synovitis of the elbow joint: anterior joint recess. Longitudinal 12−5 MHz US images over the anterior coronoid
recess a in normal state and b,c in two cases of joint synovitis presenting with b mild and c marked distention of the anterior
synovial spaces by fluid and hypertrophied synovium. In normal conditions, a thin layer of fluid (arrow) may be encountered in
the anterior coronoid recess, deep to the anterior fat pad (asterisks). This is a normal finding. When joint fluid expands into the
anterior joint spaces, the anterior fat pad (asterisks) becomes elevated to assume a typical crescentic or “sail-like” appearance.
In markedly distended joints, the anterior bulging of the joint cavity is more conspicuous and may extend down to the joint
level. HC, humeral capitellum; RH, radial head. d Corresponding T2w SE MR image of the case illustrated in b
tm
∗
O
∗
∗
tm
∗
TR
a
b
Fig. 8.68a,b. Synovitis of the elbow joint: posterior joint recess. a Longitudinal 12−5 MHz US image over the posterior olecranon
recess with b T2w SE MR imaging correlation in a patient with rheumatoid arthritis presenting with painful elbow and loss
of extension. US shows a bulk of hypoechoic synovial pannus filling the recess (arrows). Deep to the triceps muscle (tm), the
posterior fat pad (asterisks) is elevated by the pannus. Note the prominence of the tip of the olecranon (O) and the humeral
trochlea (TR) bulging within the recess
of the hyaline cartilage and subchondral bone on the
joint surfaces (Fig. 8.70). In the olecranon fossa, care
should be taken not to confuse the synovial pannus
with the normal fat pad that may appear slightly
hypoechoic (Fig. 8.71). In doubtful cases, graded
compression with the probe can help to distinguish
between them. When there are clinical concerns for
septic arthritis, US-guided aspiration of the joint fluid
can be performed (Jacobson and van Holsbeeck
1998; Lim-Dunham et al. 1995).
Elbow
∗
∗
∗
RH
∗
∗
HC
a
∗
b
Fig. 8.69a,b. Synovitis of the elbow joint: annular (periradial) recess. a Longitudinal 12−5 MHz US image over the anterior aspect
of the radio-capitellar joint with b transverse T2w SE MR imaging correlation in a patient with rheumatoid arthritis reveals
filling of the annular recess (white arrows) by hypoechoic synovial fluid (asterisks). The annular recess lies around the radial
metaphysis and communicates with the joint cavity through a thin passageway (open arrow) deep to the annular ligament. Note
the rounded profile of the humeral capitellum (HC) and the squared profile of the radial head (RH)
∗
✟
◆
✟
◆
∗
✟
◆
RH
HC
a
∗
∗
∗
RH
HC
b
Fig. 8.70a,b. Rheumatoid arthritis. a,b Longitudinal 12−5 MHz US images over the anterior aspect of the radio-capitellar joint
a in a normal subject and b in a patient with severe longstanding rheumatoid arthritis. In a, note the articular cartilage (rhombi)
and the regular profile of the subchondral bone of the humeral capitellum (HC) and radial head (RH). In b, there is complete
loss of the cartilage layer and the surface of bones appears diffusely irregular, reflecting erosions. Synovial pannus (asterisks)
can be seen within the joint space and distending the annular recess
T
LE
∗
∗
ME
T
ME
LE
a
b
Fig. 8.71a,b. Synovitis of the elbow joint: pitfall. a,b Transverse 12−5 MHz US images over the posterior olecranon recess a in a
normal subject and b in a patient with rheumatoid arthritis and an olecranon recess (arrows) appears markedly distended by
fluid. In a, the normal hypoechoic fat contained. In b the olecranon fossa, between the lateral (LE) and medial (ME) epicondyles,
should not be confused with the synovitis process shown in b. In doubtful cases, careful dynamic examination with elbow flexion
and extension movements may be helpful for the diagnosis. Note the erosion (arrowhead) on the posteromedial aspect of the
lateral epicondyle. T, distal triceps tendon
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8.5.5.2
Osteoarthritis and Osteochondral Damage
Osteoarthritis of the elbow is basically post-traumatic in nature. It is typically seen in male patients
with a history of manual labor (vibration tools),
sport-related overuse or fracture malalignment. The
dominant extremity is more frequently involved.
Given the physiologic attitude of the elbow joint to
valgus posture, the external radio-capitellar compartment is most commonly affected. Clinical findings are related to the degenerative process itself
(stiffness and loss of motion, usually extension,
related to spurring, swelling due to synovitis, local
pain), compression of the ulnar nerve inside the
cubital tunnel (local pain and tenderness, tingling
of the ring and little fingers and, in chronic compression, wasting of the ulnar-innervated intrinsic
hand muscles) as well as intra-articular loose bodies
(intermittent joint locking and effusion).
Intra-articular loose bodies commonly migrate
into the dependent portions of the joint and in the
humeral depressions above the joint line, particularly the olecranon fossa, resulting in mechanical
symptoms such as intermittent locking and loss of
extension. In patients without a synovial effusion,
the intra-articular location of a fragment can be
established by demonstrating it between the articular cartilage and the anterior and posterior intracapsular fat pads. The small radial annular recess is
rarely involved by loose bodies. Dynamic examination performed during flexion and extension of the
elbow may be helpful in mobilizing the joint fluid
and small loose bodies as well as for differentiating
br
✟
◆
them from local heterotopic ossification and spurring (Fig. 8.72) (Bianchi and Martinoli 2000). In
primary synovial chondromatosis, multiple chondral or osteochondral loose bodies typically display
nearly equal size and can vary in number from a
few to hundreds (Fig. 8.73). Advanced disease may
result in disintegration of the articular surfaces.
As already described in other anatomic sites, in
the initial phase of disease the treatment includes
removal of the loose bodies and synovectomy to
prevent recurrence. Similar to a loose body, the os
supratrochleare dorsale is an intra-articular ossicle
located in the olecranon fossa that may be associated with pain and progressive loss of elbow extension with locking symptoms (Obermann and Loose
1983). This accessory ossicle is generally believed to
be the result of a congenital anomaly rather than
the consequence of previous trauma and may cause
deepening and remodeling of the olecranon fossa
as it increases in size. Differentiation between an os
supratrochleare dorsale and a loose body is clinically
not relevant because both fragments are treated by
surgical removal.
In adolescents, US is also able to recognize deformities of the humeral capitellum in osteochondritis dissecans (Takahara et al. 1998, 2000a,b). This
condition typically occurs in 13- to 16-year-olds,
mainly as a result of chronic lateral impaction or
repetitive valgus stress. The anterolateral articular
surface of the capitellum is typically involved with
localized subchondral bone flattening and subsequent fragmentation and loosening of bone fragments (Takahara et al. 2000a). US examination
is best performed with an anterior approach while
br
✟
◆
∗
HC
a
b
Fig. 8.72a,b. Anterior spur mimicking a loose body. a Longitudinal 12−5 MHz US image with b lateral radiographic correlation demonstrates a prominent spur (arrow) over the coronoid fossa of the humerus. The spur is intracapsular in location and
appears bordered by fluid (asterisk). During elbow movements, it remained still. Note the thin hypoechoic layer of articular
cartilage (rhombi) that covers the humeral capitellum (HC). Br, brachialis muscle
Elbow
br
br
∗
✟
◆
∗
✟
◆
◆
✟
✟
◆
HC
a
b
c
d
Fig. 8.73a−d. Primary synovial chondromatosis. a Longitudinal and b transverse 12−5 MHz US images over the anterior coronoid recess demonstrate multiple intra-articular loose bodies as hyperechoic fragments (arrowheads) of similar size with
posterior acoustic shadowing lying inside the recess. Note the elevation of the anterior fat pad (asterisks) over the fragments
and the thin hypoechoic layer of articular cartilage (rhombi) that overlies the humeral capitellum (HC). br, brachialis muscle.
c Lateral radiograph and d transverse T1w GRE MR imaging of the same case showing the loose bodies (arrowheads)
keeping the elbow extended (to view the proximal
and middle parts of the anterior capitellum) and
with a posterior approach while keeping the elbow
flexed (to view the middle and distal parts of the
anterior capitellum) (Takahara et al. 2000b).
Detached bony fragments are depicted as echogenic foci in the osteochondral defect. US has also
proved to be accurate in determining whether the
lesion is stable or unstable (loosened fragments),
with good (89%) agreement with surgical findings
and MR imaging (Takahara et al. 2000b). In these
patients, delay in the appropriate management can
be avoided by an early US examination. Similar
abnormalities may be encountered in Panner disease, a condition related to avascular necrosis of
the ossification center of the capitellum that occurs
in 5–11 years old children secondary to traumatic
injures. Somewhat comparable to Legg-CalvéPerthes disease in the hip, this latter condition has
a benign outcome with no residual deformity of the
capitellum and absence of loose body formation
(Vanderschueren et al. 1998).
8.5.5.3
Occult Fractures
Due to the anatomic complexity of the elbow joint,
some undisplaced fractures, such as those involving the radial head and neck and the coronoid
process, may remain occult radiographically, even
when additional projections are performed. When
cast immobilization is not employed as a prophylactic measure to avoid overtreatment, persistent
pain and disability may lead the referring physician to acquire a US examination to rule out any
possible soft-tissue abnormality about the elbow.
With careful scanning technique, high-resolution
US is able to identify acute elbow fractures based
on detection of a step-off deformity or focal discontinuity of the hyperechoic cortical line (Fig. 8.74).
In these cases, however, additional radiographic
or MR imaging studies should always be obtained
to confirm the US diagnosis. Dynamic scanning
during careful passive-assisted pronation and
supination of the forearm with the probe placed
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br
br
C
a
HC
b
br
br
C
c
HC
d
Fig. 8.74a–d. Occult fracture of the right coronoid process in a woman following a ski accident. a The patient had a negative
radiographic examination performed soon after the injury. b Two weeks later, she was submitted to US examination due to persistent elbow pain and loss of extension. US identified an interruption (curved arrow) of the hyperechoic cortical profile of the
coronoid process (C), just cranial to the insertion of the brachialis (br). There was associated mild intra-articular effusion. HC,
humeral capitellum. c Left healthy side for comparison. d Additional oblique view of the right elbow confirms the fracture
in the transverse plane over the radial head may
be useful to exclude any fracture at this site. In
doubtful cases, associated US signs, such as joint
effusion, can be easily detected in intra-articular
fractures and may suggest a more detailed analysis of the bone contour (Major and Crawford
2002). On the other hand, the absence of effusion in
elbow injuries with negative plain radiographs may
make further bone investigation with MR imaging
unnecessary (Kessler et al. 2002). More than in
adults, US seems to have a potential role for the
evaluation of elbow fractures in children. In fact,
there are difficulties in assessing bony abnormalities about the elbow in skeletally immature patients
using plain radiographs because of the absence of
the secondary centers of ossification (Fig. 8.75).
When a radiographic sign of joint effusion is present but a fracture is not visualized, US may help in
distinguishing the separation of the distal humeral
epiphysis (Dias et al. 1988; Ziv et al. 1996) from
elbow dislocation in neonates, as well as in detecting or excluding radial head (Lazar et al. 1998)
and supracondylar fractures (Davidson et al. 1994;
Brown and Eustace 1997).
8.5.5.4
Posterior Dislocation Injury and Instability
Elbow dislocation is most common in children less
than 10 years old and accounts for 5−8% of all fractures and dislocations in adults, being second only to
the shoulder. Usually, the ulna and radius dislocate
posteriorly following a hyperextension mechanism,
such as during a fall on the outstretched hand. The
posterior translation can cause impaction fractures
(i.e., coronoid process, humeral capitellum) and a
variety of soft-tissue lesions, involving joint and
ligaments, vessels and nerves. In such cases, US can
occasionally be required to demonstrate soft-tissue
complications, such as heterotopic ossification, contusion of the brachialis muscle and injuries to the
brachial artery and the median and ulnar nerves
(Figs. 8.76, 8.77). After a dislocation, instability of
the elbow joint may result following progressive
disruption of the lateral ulnar collateral ligament
(posterolateral rotatory instability), tearing of the
anterior and posterior joint capsule and then rupture of the medial collateral ligamentous complex
(multidirectional instability).
Elbow
∗
∗
R
HC
a
∗
HC
R
b
c
Fig. 8.75a–c. Radial fracture in a 5-year-old child presenting with left lateral elbow pain and disability after a fall. a Longitudinal
12−5 MHz US image at the anterolateral elbow demonstrates increased distance between the humeral capitellum (HC) and the
radial epiphysis related to an intervening hyperechoic joint effusion (asterisks). Note the hyperechoic dot (arrowheads) within
the radial epiphysis representing the ossification center. At the radial metaphysis, US reveals a focal irregularity of the hyperechoic cortical line (arrow) suggesting a fracture. R, radius. b Contralateral healthy side for comparison. c Lateral radiograph
of the left elbow confirms the diagnosis of radial fracture (arrow)
a
br
br
br
br
a
∗
b
a
a
br
br
c
d
Fig. 8.76a–d. Partial tear of the brachialis muscle as a consequence of posterior
dislocation injury. a,b Longitudinal and
c transverse 12−5 MHz US images of the
anterior elbow obtained in the supracondylar area demonstrate a wide hypoechoic
defect (large arrows) in the substance
of the brachialis muscle (br) related to
hematoma. The torn muscle tissue is surrounded by anechoic spaces. Note the
relationship of the injured brachialis with
the normal distal biceps muscle (arrowheads), brachial artery (a) and median
nerve (curved arrow). d Contralateral
healthy side. Corresponding transverse
12−5 MHz US image shown in c reveals
an intact brachialis
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Fitzgerald SW, Curry DR, Erickson SJ et al (1994) Distal
biceps tendon injury: MR imaging diagnosis. Radiology
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Gelberman RH, Yamaguchi K, Hollstien SB et al (1998) Changes
in interstitial pressure and cross-sectional area of the cubital tunnel and of the ulnar nerve with flexion of the elbow.
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Gielen J, Wang XL, Vanhoenacker F et al (2003) Lymphadenopathy at the medial epitrochlear region in cat-scratch
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407
Forearm
9
Forearm
Carlo Martinoli and Stefano Bianchi
CONTENTS
9.2
Clinical and US Anatomy
9.1
Introduction 409
9.2
9.2.1
9.2.2
9.2.3
Clinical and US Anatomy
Volar Forearm 409
Dorsal Forearm 415
Mobile Wad 417
9.3
9.3.1
9.3.1.1
9.3.1.2
9.3.1.3
9.3.1.4
9.3.2
Forearm Pathology 417
Volar Forearm 419
Pronator Syndrome 419
Anterior Interosseous Nerve Syndrome 419
Other Compression Neuropathies 419
Penetrating Injuries 421
Dorsal Forearm and Mobile Wad 421
References
409
409
423
9.1
Introduction
Although the soft tissue anatomy of the forearm is
complex due to the high number of muscles involved
in the spectrum of wrist and fingers movements,
musculoskeletal pathology amenable to US examination is relatively uncommon in this area. Only a
few specific conditions affecting the median nerve
proximal to the carpal tunnel level merit separate
consideration.
C. Martinoli, MD
Associate Professor of Radiology, Cattedra “R” di Radiologia
– DICMI – Università di Genova, Largo Rosanna Benzi 8, 16132
Genova, Italy
S. Bianchi, MD
Privat-docent, Université de Genève, Consultant Radiologist,
Fondation et Clinique des Grangettes, 7, ch. des Grangettes,
1224 Genève, Switzerland
Strong septal attachments of the antebrachial fascia
to the radius, the ulna and the interosseous membrane divide the forearm into three distinct compartments – volar, dorsal and the so-called mobile
wad – each of which house several muscles (Fig. 9.1).
The volar compartment (flexor compartment) contains eight muscles – the flexor pollicis longus, the
flexor digitorum profundus, the flexor digitorum
superficialis, the pronator teres, the palmaris longus,
the flexor carpi radialis, the flexor carpi ulnaris
and the pronator quadratus – and the most relevant
neurovascular structures of the limb, including the
median nerve along with its main divisional branch,
the anterior interosseous nerve, the ulnar nerve and
the ulnar artery. The dorsal compartment (extensor
compartment) houses eight muscles: the supinator,
the extensor pollicis brevis, the abductor pollicis
longus, the extensor pollicis longus, the extensor
indicis proprius, the extensor digitorum communis,
the extensor digiti minimi and the extensor carpi
ulnaris. At the radial aspect of the forearm, three
other muscles – the extensor carpi radialis brevis and
longus (extensors) and the brachioradialis (flexor)
– form the so-called mobile wad. The superficial sensory branch of the radial nerve and the radial artery
run between the mobile wad compartment and the
volar compartment of the forearm. A basic review
of the compartmental normal and US anatomy of
the forearm with a description of the courses of the
radial, median and ulnar nerves is included here.
9.2.1
Volar Forearm
The volar (anterior) compartment of the forearm
includes the flexor and pronator (antebrachial) muscles. It can be divided by a transverse septum into
two layers: deep and superficial (Boles et al. 1999).
Forearm
5
7
2
6
4
1
8
3
a
b
c
Some anomalous muscles may be encountered in
the forearm, the two more common of which are the
anomalous palmaris and the Gantzer muscle. The
palmaris longus is one of the most variable muscles
in the human body, with an overall incidence of
anomalies of 9% (Reimann et al. 1944). Occasionally, its muscle belly can be found in a central position between discrete proximal and distal tendons
(digastric variant), or even distally. When located
distally, the muscle has a long proximal tendon,
an appearance resembling a “reversed” palmaris
(Schuurman and van Gils 2000). A palmaris with
double muscle bellies may also occur: in this latter
configuration, the two bellies – one proximal and
one distal – are separated by a central tendon lying
in between (Reimann et al. 1944). The Gantzer
muscle (found in approximately 52% of people) is
an accessory slip of the flexor pollicis longus which
arises from the medial epicondyle in 85% of cases
and has a dual origin from the epicondyle and the
coronoid process in the rest (Al-Quattan 1996).
It inserts onto the ulnar side of the flexor pollicis
longus and its tendon. Both anomalous palmaris
and Gantzer muscle may contribute to median and
anterior interosseous nerve compression.
The major nerves and vessels of the forearm are
located within or traverse the volar compartment
(Fig. 9.3). The median nerve enters the volar compartment passing between the superficial and deep
heads of the pronator teres muscle. It then crosses
the ulnar artery and proceeds toward depth to pass
Fig. 9.2a–c. Schematic drawings of a coronal view of
the muscles of the volar compartment of the forearm from deep (a) to superficial (c). a The deep
layer includes the flexor pollicis longus (1) and the
flexor digitorum profundus (2), which have a wide
origin from the interosseous membrane, the radius
and the ulna. Their distal tendons pass superficial to
the pronator quadratus (3) before entering the carpal
tunnel. b Superficial to these muscles, the flexor
digitorum superficialis (4) is a broad muscle which
arises from the humerus, the ulna and the radius.
Its distal tendons are disposed in series over those
of the flexor digitorum profundus. c Over the flexor
digitorum superficialis, the pronator teres (5), the
palmaris longus (6), the flexor carpi radialis (7) and
the flexor carpi ulnaris (8) originate from the medial
epicondyle. While the pronator teres traverses the
proximal forearm obliquely to insert into the radius,
the other superficial muscles lie adjacent one to the
other and descend the forearm to continue in long
distal tendons down to the wrist
below the fibrous arch formed by the flexor digitorum superficialis, the so-called “sublimis bridge”,
where it is closely apposed to the deep surface of
this muscle. At the middle forearm, the median
nerve runs in the midline, as its name indicates,
between the superficial flexor digitorum superficialis and the deep flexor digitorum profundus.
More distally, at the distal forearm, it becomes more
lateral and superficial to enter the wrist. Along its
course through the forearm, the median nerve provides motor function to the pronator teres, the flexor
carpi radialis, the flexor digitorum superficialis and
the palmaris longus. It also sends branches to the
proximal part of the flexor pollicis longus and the
flexor digitorum profundus. Approximately 5–8 cm
distal to the lateral epicondyle, the anterior interosseous nerve is a purely motor nerve which branches
off the median nerve at the level of the deep head of
the pronator teres. It travels along the anterior surface of the interosseous membrane with the anterior
interosseous branch of the ulnar artery, between the
muscle bellies of the flexor pollicis longus and flexor
digitorum profundus, and then deep to the pronator
quadratus. This nerve supplies the flexor pollicis
longus, part of the flexor digitorum profundus (for
the index and middle finger) and the pronator quadratus. After exiting the cubital tunnel, the ulnar
nerve enters the volar compartment of the forearm
passing on the anterior surface of the flexor digitorum profundus, under the flexor carpi ulnaris. At
the middle of the forearm, it is reached by the ulnar
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C. Martinoli and S. Bianchi
e
c
19
17 d
18
d
b
H
c
a
U
a
2
8
d
4
g
19
f
c
1
9
h
b
4
g8
R 1,2
d
U
a
e
3
f b
a
5
4
9
b
e
BT
BA
b
c
b
f 7
c
3
2,4
g8
a
R
U
f
Fig. 9.3a–f. Schematic drawings of coronal (a–c) and transverse (d–f) views through the forearm
showing the main nerves (in black) and arteries (in white) and their relationships with surrounding
bones and muscles. a Basically, the forearm is crossed by three main neurovascular pedicles: ulnar,
central and radial. The ulnar pedicle is formed of the ulnar nerve (a) and the ulnar artery (g); the
central pedicle consists of the median nerve (b) and the anterior interosseous nerve (h), the latter
arising from it at the middle third of the forearm; the radial pedicle includes the superficial branch
of the radial nerve (c) and the radial artery (f). The course of the Martin–Gruber anastomosis is
indicated by a dashed line. At the elbow level, note the position of the brachial artery (e) and the
posterior interosseous nerve (d). b,c Main forearm muscles located b deep and c superficial to the
neurovascular bundles illustrated in a. Note the relationship of the nerves and arteries with the supinator (9), the flexor pollicis longus (1), the flexor digitorum profundus (2), the pronator quadratus
(3), the flexor digitorum superficialis (4) and the flexor carpi ulnaris (8) muscles. d–f The relationship of the nerves and arteries with the muscles of the forearm compartments is demonstrated at the
level of the elbow (a), the middle (b) and the distal (c) forearm. The individual anatomic structures
are indicated with the same numbers and letters used in Figs. 9.1 and 9.2. H, humerus; U, ulna; BA,
brachialis; BT, biceps tendon; R, radius
artery and its satellite veins. Thereafter, the nerve
and vessels proceed distally together, emerging on
the radial side of the flexor carpi ulnaris tendon,
between this tendon and the tendon of the flexor
digitorum superficialis for the little finger to enter
the Guyon canal. In the forearm, the ulnar nerve supplies the flexor carpi ulnaris and the ulnar portion
of the flexor digitorum profundus. In up to 30% of
people, a crossover of fibers from the median nerve
to the ulnar nerve – the Martin–Gruber anastomosis
– occurs at the proximal forearm. This anastomosis can be responsible of anomalous innervation of
intrinsic hand muscles and thus can lead to unclear
clinical presentation of some nerve entrapment syndromes (Fig. 9.3a).
The two main arteries in the forearm are the radial
and the ulnar arteries, which are terminal divisions
of the brachial artery (Fig. 9.3). The ulnar artery travels through the volar compartment with the ulnar
nerve. It arises at the level of the neck of the radius,
just medial to the distal biceps tendon, and courses
deep to the “sublimis bridge” accompanied by the
median nerve. At the middle third of the forearm,
the ulnar artery traverses posterior to the median
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fcr
pl
fcu
fds
MN
prt
fpl
UN
fdp
R
U
a
pl
fcr
fds
MN
fcu
fds
UN
fdp
fpl
R
U
b
MN
RN
fcu
fds
fpl
Fig. 9.5a,b. Volar compartment of the forearm. a,b Transverse 12–5 MHz US images
obtained a just distal to the sublimis bridge
and b, more caudally, at the middle third of
the forearm demonstrate the relationships
of the deep muscles – the flexor pollicis
longus (fpl) and the flexor digitorum profundus (fdp) – with the superficial muscles – the pronator teres (prt), the flexor
carpi radialis (fcr), the flexor digitorum
superficialis (fds), the flexor carpi ulnaris
(fcu) and the palmaris longus (pl) – of the
volar forearm. The two layers of muscles
are separated by a transverse hyperechoic
cleavage plane (curved arrows) representing an extension of the antebrachial fascia
within which the median nerve (MN), the
ulnar nerve (UN) and the ulnar artery
(straight arrow) are found. From proximal
(a) to distal (b), observe the muscle belly
of the palmaris longus which continues
in a thin superficial tendon. R, radius; U,
ulna. The photograph at the right of the
figure indicates probe positioning
fdp
UN
AIN
b
MN
fds
fpl
R
a
c
AIN
fdp
U
Fig. 9.6a-c. Anterior interosseous nerve. a Schematic drawing of a coronal view of the elbow after removal of the distal tendon of
the biceps brachii (bb) the distal part of the brachialis (ba) and the superficial belly of the pronator teres muscle (prt) reveals the
course of the median nerve (arrow) in the pronator area and the origin of the anterior interosseous nerve (arrowheads) deep to
the flexor digitorum superficialis muscle (fds). b Schematic drawing of a transverse view through the middle forearm illustrates
the close relationship of the anterior interosseous nerve (AIN) with the anterior aspect of the interosseous membrane (arrow) and
the bellies of the flexor pollicis longus (fpl) and flexor digitorum profundus (fdp). The anterior interosseous nerve runs in a deeper
position compared with the median nerve (MN). Observe the ulnar nerve (UN) which courses between the flexor carpi ulnaris (fcu),
the flexor digitorum profundus (fdp) and the flexor digitorum superficialis (fds) muscles. RN, superficial sensory branch of the
radial nerve. c Transverse 12–5 MHz US images obtained over the volar compartment at the middle forearm reveal the respective
position of the median (MN) and anterior interosseous (AIN) nerves relative to the flexor digitorum superficialis (fds), the flexor
digitorum profundus (fdp), the flexor pollicis longus (fpl) and the interosseous membrane (arrows). R, radius; U, ulna
Forearm
MN
MN
UN
UN
a
R
U
b
R
U
MN
UN
Fig. 9.7a–c. Ulnar artery. a–c Transverse 12–5 MHz US images obtained
from a proximal to c distal reveal the ulnar artery (straight arrow)
which traverses the forearm leaving the median nerve (MN) to reach
the ulnar nerve (UN). R, radius; U, ulna. The photograph at the upper
right of the figure indicates probe positioning
the best ways to identify the bellies of the superficial
flexors (flexor carpi radialis, flexor carpi ulnaris and
palmaris longus) and the flexor pollicis longus is to
start scanning over their distal tendons and then
sweep the probe proximally on transverse planes.
The scanning technique to examine these tendons
and the pronator quadratus will be addressed later
(see Chapter 10).
U
R
c
a
9
14
b
16
11
9.2.2
Dorsal Forearm
Similar to the volar compartment, the muscles of
the dorsal (posterior) compartment of the forearm,
can be arbitrarily divided in two layers: deep and
superficial. The deep muscles include the supinator, the extensor pollicis brevis, the abductor pollicis
longus, the extensor pollicis longus and the extensor
indicis proprius (Fig. 9.8a). The anatomy of the supinator muscle and its relationships with the posterior
interosseous nerve has already been described (see
Chapter 8). The remaining four muscles take their
origin from the posterior aspect of the radial and
ulnar shaft and from the interosseous membrane
distal to the position of the supinator muscle. They
insert into the metacarpal (abductor pollicis longus),
15
12
13
a
10
b
Fig. 9.8a,b. Schematic drawings of a coronal view of the a deep
and b superficial muscles of the dorsal compartment of the
forearm. a The deep layer of muscles includes the supinator
(9), consisting of two heads – superficial (a) and deep (b) – and,
more distally, the abductor pollicis longus (11), the extensor
pollicis brevis (10), the extensor pollicis longus (12) and the
extensor indicis proprius (13). These latter muscles originate
from the posterior aspect of the radial and ulnar shaft and the
interosseous membrane. b In a more superficial position, the
extensor digitorum communis (14), the extensor digiti minimi
(15) and the extensor carpi ulnaris (16) are found arising from
the lateral epicondyle of the humerus
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the proximal (extensor pollicis brevis) and the distal
phalanx (extensor pollicis longus) of the thumb, and
the middle and distal phalanx of the index finger
(extensor indicis proprius) respectively. From lateral
to medial, the abductor pollicis longus is the largest
and most superficial muscle of the group. Close to
it, the extensor pollicis brevis lies in a more distal
position and is partially covered by the abductor.
The extensor pollicis longus is larger and its tendon
is longer than the brevis. Finally, the extensor indicis
proprius is narrow and elongated, and lies medial
to and alongside the extensor pollicis longus. Apart
from the abductor pollicis longus which abducts and
extends the thumb, the other deep extensors act to
extend the phalanges. From lateral to medial, the
extensor muscles of the superficial layer include the
extensor digitorum communis, the extensor digiti
minimi and the extensor carpi ulnaris (Fig. 9.8b). In
association with the extensor carpi radialis brevis,
these muscles share a proximal strong tendon that
originates from the lateral epicondyle of the humerus
(see Chapter 8). The extensor digitorum longus and
extensor digiti minimi insert onto the middle and
distal phalanges of the four medial fingers (extensor digitorum longus) and the little finger (extensor
digiti minimi). The extensor carpi ulnaris inserts
distally into the base of the fifth metacarpal. On the
whole, the superficial extensor muscles are innervated by distal branches of the radial nerve (posterior
interosseous nerve). As a functional part of the long
head of the triceps, the anconeus muscle has already
been described in Chapter 8.
As a rule, an accurate and systematic US examination of the dorsal muscles of the forearm should
begin at the level of the wrist, where their individual tendons are easily distinguished within the
six compartments. Then, US scanning should be
performed by shifting the transducer upward to
depict the myotendinous junction and the belly of
the appropriate muscle to be evaluated. This “retrograde” technique is particularly helpful, even for
the experienced examiner, to increase confidence on
establishing the identity of the forearm muscles. At
the middle third of the dorsal forearm, the muscle
bellies of the superficial and deep layers are divided
by a transverse hyperechoic septum (Fig. 9.9). More
deeply, the hyperechoic straight appearance of the
interosseous membrane and the profile of the radial
and ulnar shafts separate the dorsal compartment
from the volar compartment (Fig. 9.9).
a
b
a
Edc
Edm
Ecu
Apl
R
b
Epb
Volar
Epl
U
Fig. 9.9a,b. Dorsal compartment of the forearm. a Proximal and b distal transverse 12–5 MHz US images obtained at the middle
third of the forearm reveal the two layers of extensor muscles located over the posterior aspect of the interosseous membrane
(arrowheads) and seperated by a transverse hyperechoic septum (arrows). From lateral to medial, the superficial layer of muscles includes the extensor digitorum communis (Edc), the extensor digiti minimi (Edm) and the extensor carpi ulnaris (Ecu),
whereas the deep layer houses the abductor pollicis longus (Apl), the extensor pollicis brevis (Epb) and the extensor pollicis
longus (Epl). R, radius; U, ulna. The photograph at the upper right of the figure indicates probe positioning
Forearm
9.2.3
Mobile Wad
The mobile wad, which is also referred to as the
radial group of forearm muscles, contains two wrist
extensors (the extensor carpi radialis brevis and the
extensor carpi radialis longus) and a forearm flexor
(the brachioradialis). These muscles lie in a radial
position compared with the ventral and the dorsal
muscles of the forearm (Fig. 9.10). The extensor carpi
radialis longus and the brachioradialis are the most
superficial and lateral. Both arise from the supracondylar ridge of the humerus and the lateral intermuscular septum, more cranially than the extensor
carpi radialis brevis. The brachioradialis is a large
muscle forming the lateral boundary of the cubital
fossa (Fig. 9.10a). Distally, it inserts onto the lateral
surface of the distal end of radius, just proximal to
the radial styloid. Although acting as a flexor of the
elbow, the brachioradialis is innervated by the radial
nerve, like an extensor muscle. Partially covered
by the brachioradialis, the extensor carpi radialis
longus lies between it and the extensor carpi radialis
brevis (Fig. 9.10). The extensor carpi radialis brevis
arises more distally than the longus and is partially
overlapped by it. The tendons of the extensor carpi
radialis muscles pass through the anatomic snuffbox to insert into the dorsal aspect of the base of
the second (longus) and third (brevis) metacarpals.
Both muscles extend and abduct the wrist joint. The
US scanning technique to examine the muscles of
the mobile wad does not differ significantly from
that used for the dorsal compartment (Fig. 9.11).
The superficial sensory branch of the radial nerve
and the radial artery are located between the mobile
wad compartment and the volar compartment of
the forearm (Fig. 9.3a). After branching off the main
trunk of the radial nerve, the superficial radial nerve
initially travels with the radial artery deep to the brachioradialis. It then passes between that muscle and
the extensor carpi radialis longus to emerge from
under the lateral boundary of the brachioradialis
(Fig. 9.12a). At the distal forearm, this nerve pierces
the antebrachial fascia and becomes subcutaneous,
providing sensory innervation for the dorsum of the
hand, the first web space and the proximal phalanges
of the three radial fingers (Fig. 9.12b,c). While crosing the fascia, the radial nerve can be compressed in
the scissoring of the brachioradialis and the extensor
carpi radialis longus during pronation and supination of the forearm. At this site, dynamic US can show
transverse sliding of the nerve during pronation and
supination movements. The radial artery is located
18
19
a
17
b
Fig. 9.10a,b. Schematic drawings of a coronal view of the
mobile wad compartment of the forearm illustrated a without and b with removal of the brachioradialis muscle. a The
brachioradialis (19) is a large palpable muscle arising from the
supracondylar ridge of the humerus and the lateral intermuscular septum which continues distally with a long and strong
tendon. b More deeply, the extensor carpi radialis brevis (17)
and the extensor carpi radialis longus (18), the first arising
from the lateral epicondyle, the second from the supracondylar ridge of the humerus, descend in the forearm in association
with the brachioradialis
more lateral and superficial compared with the ulnar
artery. Initially, it is covered by the brachioradialis
and then becomes more superficial at the middle and
distal thirds of the forearm, where it runs between the
brachioradialis and the flexor carpi radialis tendons.
9.3
Forearm Pathology
Similar to the arm, musculoskeletal pathology affecting muscles and tendons is uncommon in the forearm and, for the most part, should derive from open
wounds, contusion or penetrating trauma. Although
unusual, there are some peculiar pathologic conditions affecting the median nerve in the proximal forearm as well as its main divisional branch, the anterior
interosseous nerve, which may give rise to pain in
the volar aspect of the forearm and weakness of the
innervated flexor muscles. These conditions include
pronator syndrome and anterior interosseous nerve
syndrome. To the best of our knowledge, the latter
is the only one which has received attention in the
imaging literature.
417
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C. Martinoli and S. Bianchi
Ecrb
BrRad
Ecrl
a
H
Br
a
Ecrb
BrRad
Ecrl
a
R
b
SH
Ecrb
DH
DH
R
U
c
Fig. 9.11a–c. Mobile wad compartment
of the forearm. a–c Series of transverse
12–5 MHz US images obtained at the
elbow and the proximal forearm from
a proximal to c distal reveal the bulk
of muscles of the mobile wad, consisting of the brachioradialis (BrRad), the
extensor carpi radialis longus (Ecrl)
and the extensor carpi radialis brevis
(Ecrb). The relationships of these muscles with the posterior interosseous
nerve (arrowhead), the superficial sensory branch of the radial nerve (arrow),
the radial artery (a) and the superficial
(SH) and deep (DH) heads of the supinator muscle are shown. Br, brachialis;
H, humerus; R, radius; U, ulna. The photograph at the upper right of the figure
indicates probe positioning
*
*
BrRad
ECRL
R
R
R
a
b
c
Fig. 9.12a–c. Superficial branch of the radial nerve. a–c Series of transverse 15–7 MHz US images obtained at the distal forearm
from a proximal to c distal. a The superficial radial nerve (arrow) courses just deep to the antebrachial fascia (arrowhead)
between the brachioradialis muscle (BrRad) and tendon (asterisk) and the extensor carpi radialis longus (ECRL). b More distally, it crosses the fascia and c moves to the subcutaneous tissue. R, radius. The photograph at the right of the figure indicates
probe positioning
Forearm
9.3.1
Volar Forearm
9.3.1.1
Pronator Syndrome
Pronator syndrome is an insidious entrapment neuropathy of the median nerve in the proximal volar
forearm. In this syndrome, the compression may
occur either in the area where the nerve traverses
deep to the lacertus fibrosus of the biceps, or as it
crosses between the two heads of the pronator teres,
or as it passes under the fibrous arch (sublimis bridge)
of the flexor digitorum superficialis. Hypertrophy of
the pronator teres, aberrant fibrous bands connecting
the pronator teres to the tendinous arch of the flexor
digitorum superficialis or the flexor carpi radialis
with the ulna, direct trauma and forearm–elbow
fractures have been reported as the possible causes.
The main clinical features of this uncommon and
somewhat controversial clinical entity are aching in
the proximal volar forearm or distal arm, typically
exacerbated by repetitive pronation and supination
movements paresthesias in one or more of the radial
three and a half fingers and weakness of the flexor pollicis and abductor pollicis longus with intact forearm
pronation. Nocturnal pain (so typical of carpal tunnel
syndrome) is usually not seen in these patients. Diagnosis of pronator syndrome is essentially based on
clinical signs and symptoms and should be considered seriously when median nerve disturbances are
not relieved after carpal tunnel release. The role of
diagnostic imaging has not yet been assessed in this
neuropathy. US could reinforce the likelihood that
a pronator syndrome is present, when asymmetry
of the pronator teres (the belly of the affected side
larger than the contralateral side) and local flattening, distortion and an abnormal course of the nerve
between the heads of the pronator or beneath the
arcade of the flexor digitorum superficialis are seen
(Fig. 9.13). Initial treatment of pronator syndrome is
conservative because many patients recover over the
course of a few months. In the remaining patients,
surgical decompression of the nerve below the elbow
(possibly associated with carpal tunnel release) is
successful in many cases.
9.3.1.2
Anterior Interosseous Nerve Syndrome
The entrapment of the anterior interosseous nerve in
the forearm, a condition also known as the Kiloh–
Nevin syndrome (Kiloh and Nevin 1952), occurs
where the nerve branches off the median nerve, in
proximity to the pronator teres and the tendinous
bridge connecting the heads of the flexor digitorum
superficialis (Stern 1984). The anterior interosseous
nerve may be compressed alone or together with the
main trunk of the median nerve by a variety of conditions, such as fibrous bands arising from the pronator
teres and the flexor digitorum superficialis, hypertrophied anomalous muscles (Gantzer muscle) and
accessory tendons from the flexor digitorum superficialis to the flexor pollicis longus. Similar to pronator
syndrome, an isolated anterior interosseous neuropathy leads to pain in the volar forearm and difficulty
in performing pinching movements with the digits
(formation of a triangle instead of a circle with the
first two digits) and handwriting. The thenar muscles
are spared and there is no sensory loss (Fig. 9.14a).
Muscle weakness is typically limited to the flexor
pollicis longus, the flexor digitorum profundus to the
index finger (middle finger also involved in 50% of
cases), and the pronator quadratus (Fig. 9.14a). Differential diagnosis includes brachial plexus lesion and
selective injury to the fibers of the median nerve at the
elbow or in the arm that are destined to become the
anterior interosseous nerve. In general, US examination of the anterior interosseous nerve is inconclusive
in the absence of a mass because this nerve is too
small and located deeply in the forearm. In rare cases,
however, the nerve and its fascicles may appear swollen compared with the contralateral side (Fig. 9.14c).
Besides direct nerve assessment, US diagnosis of an
overt anterior interosseous neuropathy may be suggested by loss in bulk and increased reflectivity of
the innervated muscles: the flexor pollicis longus, the
flexor digitorum profundus and the pronator quadratus (Fig. 9.14d) (Grainger et al. 1998; Hide et al.
1999; Martinoli et al. 2004).
9.3.1.3
Other Compression Neuropathies
Because of their free, unconstricted course, the
radial and ulnar nerves are rarely compressed in
the forearm. A reported site of compression of the
sensory branch of the radial nerve is its point of
emergence between the tendons of the brachioradialis and the extensor carpi radialis longus in the
distal forearm. Repeated pronation and supination
of the forearm is believed to be contributory to
positional impingement of the nerve in the scissoring of these two tendons. From the biomechanical
419
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C. Martinoli and S. Bianchi
a
prt
*
d
br
*
*
e
a
a
a
prt
prt
prt
prt
b
c
f
Fig. 9.13a–f. Pronator syndrome in a patient with persisting symptoms of median neuropathy irradiated to the volar forearm
and wrist after carpal tunnel release. a Transverse 12–5 MHz US image obtained at the elbow level, over the medial edge of
the humeral trochlea (asterisk) demonstrates a flattened median nerve (arrow) presenting with an abnormal medial course
between the pronator teres (prt) and the brachialis (br). a, brachial artery. b More distally, in the pronator area, transverse
12–5 MHz US image shows the flattened median nerve (arrow) coursing between the two heads of the pronator teres (prt).
The nerve lies more medially than expected and not so closely associated with the ulnar artery (a). This anomaly suggested
positional entrapment of the median nerve in the pronator area. c Contralateral normal side. Note the rounded cross-sectional
profile of the normal median nerve (arrow) which runs adjacent to the ulnar artery (a). prt, pronator teres. d,e Transverse
d T1-weighted and e fat-suppressed T2-weighted MR images of the elbow confirm flattening of the median nerve (arrow)
which appears slightly hyperintense in the T2-weighted sequence. Asterisk, medial edge of the humeral trochlea. f Schematic
drawing of a coronal view of the elbow after removal of the distal tendon of the biceps brachii (bb), the brachialis muscle and
the superficial belly of the pronator teres (prt) reveals the abnormal course of the median nerve (arrows) in the pronator area
described in this particular case. Arrowheads, brachial artery
point of view, the nerve is anchored by fascia at this
site and cannot adjust its position as the adjacent
tendons do. Patients complain of pain and burning
sensation over the dorsoradial aspect of the forearm,
which increase in intensity with palmar flexion
and ulnar deviation of the wrist or quick repeated pronation and supination movements. More
distally, the entrapment of the sensory branch of
the radial nerve may occur around the radial aspect
of the wrist, so-called Wartenberg syndrome (see
Chapter 10). On the mid-distal forearm, ulnar nerve
compression may occur from casts positioned for
wrist fractures or may be related to direct injuries,
including contusion trauma (from a direct blow)
or penetrating wounds. In contusion trauma, there
may be discrepancy between severity of clinical pic-
ture and normal electrodiagnostic studies. Tinel’s
sign is usually positive on the ulnar aspect of the
forearm. US can assess whether a nerve abnormality
(fusiform neuroma) exists at the lesion site and may
help the clinician to decide which is the most appropriate treatment (conservative vs. operative) to be
instituted. In the area between the pronator and the
carpal tunnel, the median nerve may occasionally be
compressed by space-occupying masses (i.e., lipomas, ganglion cysts) or anomalous muscles. Among
them, a reversed palmaris can produce a mass effect
on the flexor tendons and the median nerve at the
distal forearm (Depuydt et al. 1998). In these cases,
US is an ideal means to reveal dynamic impingement
of the median nerve by the anomalous muscle at rest
and during contraction (Fig. 9.15).
422
C. Martinoli and S. Bianchi
fcr
ft
fds
fpl
fdp
pq
c
pq
R
ft
b
fcr
*
a
fds
*
ft
d
e
fcr
* *
f
g
Fig. 9.15a–g. Reversed palmaris muscle and carpal tunnel syndrome. a Photograph of a woman presenting with a fusiform soft
tissue lump (arrowheads) in the volar wrist and clinical symptoms of carpal tunnel disease. The lump increases in size and stiffness while clenching the fist. b Transverse and c longitudinal 12–5 MHz US images over the mass reveal an additional muscle belly
(white arrows) over the flexor digitorum superficialis muscle (fds) and tendons (ft), reflecting a reversed palmaris. In a, observe
the median nerve (open arrow) and other adjacent deep muscles, the flexor pollicis longus (fpl), the flexor digitorum profundus
(fdp) and the pronator quadratus (pq). R, radius. d Transverse 12–5 MHz US image over the anomalous muscle obtained during
contraction. Active contraction leads to an increased thickness of the muscle belly. This change can be easily palpated at physical
examination and would lead to compression on the underlying median nerve (arrow). Note tenosynovial effusion (asterisks) in
the sheath of the flexor tendons (ft) and the normal flexor carpi radialis tendon (fcr). e Transverse 12–5 MHz US image obtained
at the proximal forearm demonstrates a long thin tendon (arrowheads) of the palmaris instead of the muscle belly. The anomalous
tendon is located superficial to the flexor digitorum superficialis. f Axial T1-weighted and g sagittal fat-suppressed T2-weighted
MR images reveal the anomalous reversed palmaris (arrows), a hyperintense appearance of the median nerve (arrowheads) in the
T2-weighted sequence and fluid effusion (asterisks) in the flexor tendon sheath reflecting tenosynovitis
c
Radius
a
b
d
Fig. 9.16a–d. Flexor carpi radialis tendon tear. a Photograph of a boy complaining of weakness of wrist flexion and a soft tissue
lump (white arrows) on the volar aspect of the wrist after receiving a penetrating wound (open arrow) in the middle forearm
by a sharp object. b Longitudinal and c transverse 12–5 MHz US images over the distal lump reveal a retracted tendon end
(arrows) of the flexor carpi radialis which appears swollen and diffusely hypoechoic. d At the level of the wound, transverse
12–5 MHz US image demonstrates an empty sheath (arrowheads) of the flexor carpi radialis tendon
Forearm
a
R
a
a
R
b
R
c
a
d
References
Al-Quattan MM (1996) Gantzer’s muscle. An anatomical study
of the accessory head of the flexor pollicis longus muscle. J
Hand Surg [Br] 21:269–270
Boles CA, Kannan S, Cradwell AB (1999) The forearm: anatomy
of muscles compartments and nerves. AJR Am J Roentgenol 174:151–159
Depuydt KH, Schuurman AH, Kon M (1998) Reversed palmaris longus muscle causing effort-related median nerve
compression. J Hand Surg [Br] 23:117–119
Grainger AJ, Campbell RSD, Stothard J (1998) Anterior interosseous nerve syndrome: appearance at MR imaging in three
cases. Radiology 208:381–384
Hide IG, Grainger AJ, Naisby GP et al (1999) Sonographic findings in the anterior interosseous nerve syndrome. J Clin
Ultrasound 27:459–464
Fig. 9.17a–d. Complete tear of the superficial branch
of the radial nerve by a glass wound. a–c Series of
transverse 12–5 MHz US images of the middle third
of the forearm obtained a proximal to, b at the level
of and c distal to the cut line. In a, note the superficial course of the radial nerve (straight arrow) which
runs closely associated with the radial artery (a). In
b and c, two adjacent neuromas are found connected
with the proximal (white arrowhead) and distal (open
arrowhead) stumps of the severed nerve. R, radius. d
Photograph shows the cut line (arrow) at the middle
third of the forearm.
Kiloh LG, Nevin S (1952) Isolated neuritis of the anterior interosseous nerve. Br Med J 1:850–851
Martinoli C, Bianchi S, Pugliese F et al (2004) Sonography
of entrapment neuropathies in the upper limb (wrist
excluded). J Clin Ultrasound 32:438–450
Reimann AF, Daeseler EH, Anson BJ et al (1944) The palmaris
longus muscle and tendon: a study of 1600 extremities.
Anat Rec 89:495–505
Sallomi D, Janzen DL, Munk PL et al (1998) Muscle denervation
patterns in upper limb nerve injuries: MR imaging findings
and anatomic basis. AJR Am J Roentgenol 171:779–784
Schuurman AH, van Gils APG (2000) Reversed palmaris
longus muscle on MRI, report of four cases. Eur Radiol
10:1242–1244
Stern MB (1984) The anterior interosseous nerve syndrome
(the Kiloh-Nevin Syndrome): report and follow-up study
of three cases. Clin Orthop 187:223–227
423
Wrist
10
Wrist
Stefano Bianchi and Carlo Martinoli
CONTENTS
10.1
Introduction 425
10.2
10.2.1
10.2.2
10.2.3
Clinical Anatomy 425
Osseous and Articular Anatomy
Tendons and Retinacula 427
Neurovascular Structures 430
10.3
Essentials of Clinical History and
Physical Examination 433
De Quervain Disease 433
Carpal Tunnel Syndrome 433
10.3.1
10.3.2
10.4
10.4.1
10.4.2
US Scanning Technique and
Normal US Anatomy 434
Dorsal Wrist 434
Volar Wrist 441
10.5
10.5.1
10.5.2
10.5.3
10.5.4
Wrist Pathology 449
Dorsal Wrist Pathology 449
Ventral Wrist Pathology 456
Bone and Joint Disorders 472
Wrist Masses 483
References
425
425
492
10.1
Introduction
In recent years, substantial improvement in transducer technology has led to a growing interest in the
US evaluation of the hand and wrist (Bianchi et al.
1999, 2001; Chiou et al. 2001; Creteur and Peetrons
2000; Ferrara and Marcelis 1997; Fornage and
Rifkin 1988; Lee 1998; Milbrat et al. 1990; Read
et al. 1996; Teefey et al. 2000; Lee and Healy 2005).
US transducers with frequencies ranging from 10 to
15 MHz allow accurate assessment of tendons, joints,
nerves and vessels of the extremities without requiring stand-off pads. The association of standard radiographs with high-resolution US works well in the
S. Bianchi, MD
Privat-docent, Université de Genève, Consultant Radiologist,
Fondation et Clinique des Grangettes, 7, ch. des Grangettes,
1224 Genève, Switzerland
C. Martinoli, MD
Associate Professor of Radiology, Cattedra “R” di Radiologia
– DICMI – Università di Genova, Largo Rosanna Benzi 8, 16132
Genova, Italy
evaluation of wrist and hand disorders. Radiographs
can recognize most bone and joint disorders and US
can be used to assess a wide spectrum of pathologic
conditions affecting soft-tissue structures.
10.2
Clinical Anatomy
From the anatomic point of view, the wrist is complex.
For this reason, we will take a little time here to review
the basic anatomy of the wrist with emphasis on the
structures that can be assessed with US.
10.2.1
Osseous and Articular Anatomy
The wrist is composed of eight carpal bones arranged
in two rows: proximal and distal. From lateral to medial,
the proximal row includes the scaphoid, lunate, triquetrum and pisiform, whereas the distal row is formed
by the trapezium, trapezoid, capitate and hamate. The
arrangement of the carpal bones forms a ventral concavity which is transformed in an osteofibrous tunnel,
the carpal tunnel, by the transverse carpal ligament.
There are three joints in the wrist which, in normal
conditions, do not communicate with one another: the
distal radio-ulnar, radiocarpal and midcarpal joints
(Fig. 10.1). Wrist movements are obtained by the concurrent action of the radiocarpal joint and midcarpal
joint: wrist flexion and extension is produced half at
the radiocarpal joint and half at the midcarpal joint,
whereas radial and ulnar deviation of the wrist involves,
at a higher extent (60%), the midcarpal joint.
10.2.1.1
Distal Radio-ulnar Joint
The distal radio-ulnar joint articulates the rounded
head of the ulna with the ulnar notch of the distal
Wrist
carpal space which increase stability to the ulnar
side of the wrist and the distal radio-ulnar joint and
absorb mechanical forces across the ulnar side of the
wrist during axial loading. The complex includes the
triangular fibrocartilage itself and other supporting
structures which blend with it, such as the meniscus
homologus, the ulnar collateral ligament, the volar
and dorsal radio-ulnar ligament and the sheath of the
extensor carpi ulnaris tendon. The triangular fibrocartilage is a biconcave disk positioned between the
ulnar styloid and the radius. Its thickness is inversely
proportional to the degree of ulnar variance.
Even using high-resolution transducers, most wrist
ligaments are not visible with US and their proper
evaluation requires MR imaging, MR arthrography
or thin collimation spiral CT arthrography. Clinically
relevant structures that are amenable to US examination are the scapholunate ligament and the triangular
fibrocartilage complex.
10.2.2
Tendons and Retinacula
The wrist is crossed by flexor and extensor tendons
which course along its ventral and dorsal aspects
respectively. Among them, nine flexor tendons and
nine extensor tendons move toward the fingers without any attachment to the carpal bones; two primary
wrist flexors and three wrist extensors insert onto
the distal carpal row and the metacarpals; and one
tendon, the palmaris longus tendon, attaches to the
transverse carpal ligament and to the palmar aponeurosis.
10.2.2.1
Extensor Tendons
The extensor tendons course over the dorsal aspect of
the wrist. They run within series of adjacent osteofibrous tunnels delimited by depressions of the surface
of radius and ulna and by the extensor retinaculum,
a 2 cm wide thickening of the dorsal fascia attached
to the radial styloid laterally and to the pisiform and
triquetrum medially. From the deep surface of the
retinaculum, vertical fibrous bands insert into the
cortical bones, at both sides of the tendons, dividing
the extensor tunnel into six compartments numbered
from radial (I) to ulnar (VI). In each compartment, a
single synovial sheath formed by visceral and parietal
layers surrounds one or more tendons (Fig. 10.2). A
variable amount of fatty tissue fills the space between
the synovial sheath and the bone surface. From the
biomechanical point of view, these tunnels give lateral
stabilization and avoid bowstringing of the extensor
tendons during wrist and finger movements. A bony
protuberance, the Lister tubercle, is found between
the second and third tunnels, acting as a useful landmark in the US identification of these compartments
(Fig. 10.2).
The first compartment, the most radial, contains
the abductor pollicis longus and extensor pollicis
brevis tendons (Fig. 10.3). Medial to this, the second
compartment houses the extensor carpi radialis
longus and brevis which insert on the dorsal aspect of
the base of the second and third metacarpals respectively. The third compartment contains the extensor
pollicis longus. As already stated, this compartment is
separated from the second one by the Lister tubercle
of the radius (Fig. 10.3a). The fourth compartment is
wide and encloses the tendons of the extensor digitorum for the second through the fifth fingers, and
the tendon of the extensor indicis proprius, which is
absent or rudimentary in approximately 40% of individuals (Fig. 10.4). The fifth compartment encloses
the extensor digiti quinti proprius, whereas the sixth
compartment, the most ulnar, includes the extensor
carpi ulnaris tendon which courses along the dorsomedial aspect of the distal ulna to insert onto the base
of the fifth metacarpal (Fig. 10.4). The tendons of the
first compartment and the tendon of the extensor
pollicis longus form the volar and dorsal boundaries of the anatomic snuff-box, a skin depression on
the radial aspect of wrist crossed by the radial artery
(Fig. 10.3a,b). To recall the exact name of the extensor tendons seems difficult but it is even harder to
remember the exact position of them in each individual compartment, and especially in the first, second
and fourth compartments. For an easier comprehension, one should keep in mind that: in the first compartment the extensor pollicis brevis tendon is more
dorsal than the abductor pollicis longus; in the second
compartment, the extensor carpi radialis brevis
tendon is closer to the Lister tubercle than the extensor carpi radialis longus; in the fourth compartment,
the extensor indicis proprius tendon is positioned on
the ulnar side of the tendon for the index finger of the
extensor digitorum; the tendon of the extensor pollicis longus crosses the tendons of the second compartment to reach the thumb (Fig. 10.3a,b). As a memo,
the tendons from the first to the third compartment
alternate as to longus and brevis as they proceed in
an ulnar direction: abductor pollicis longus, extensor
pollicis brevis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor pollicis longus.
427
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S. Bianchi and C. Martinoli
III
))
))
II
)))
)))
IV
(EPL) (EIP, EDC)
(ECRB, ECRL)
)6
)6
V
VI
(EDQ)
(ECU)
6
6
)
6)
6)
Radius
I
Ulna
(EPB, APL)
b
III
II
a
V
IV
Ulna
Radius
c
Fig. 10.2 a−c. Position of the extensor tendons relative to the bony surfaces of the dorsal radius and ulna. a Dorsal aspect of the
wrist bones illustrates the relationships of the six compartments of the extensor tendons (I−VI) with the Lister tubercle (arrow).
b Schematic drawing of a transverse view at the level of the distal radio-ulnar joint outlines the extensor tendons and their synovial
sheath. The tendons are labeled with numbers that correlate with the dorsal compartments (I−VI). The first compartment contains
the abductor pollicis longus (APL) and extensor pollicis brevis (EPB), the second the extensor carpi radialis longus (ECRL) and
extensor carpi radialis brevis (ECRB), the third the extensor pollicis longus (EPL), the fourth the extensor indicis proprius (EIP)
and extensor digitorum (EDC), the fifth the extensor digiti quinti (EDQ), the sixth the extensor carpi ulnaris (ECU). Observe the
prominence of the Lister tubercle (arrow) which separates the second from the third compartment. c Transverse 15−8 MHz US
image over the dorsal wrist illustrates the typical dorsal shape of the distal radius and ulna shown in the diagram in b. The depiction of the Lister tubercle (arrow) makes the identification of the overlying extensor tendons easier
P
∗
IV
R
III
I
a
b
c
Fig. 10.3 a−c. Anatomic snuff-box. a Schematic drawing of a coronal view of the wrist bones illustrates the relationship among the
tendons of the first (I), second (II) and third (III) compartments. Note the course of the extensor pollicis longus tendon (III) which
crosses the tendons of the second compartment to reach the thumb. The anatomic snuff-box (arrow) is a triangular space delimited by the tendons of the first and third compartments. b Photograph of the dorsolateral aspect of the wrist in a young woman
showing the main surface features visible during contraction of the radial extensors. The abductor pollicis longus and extensor
pollicis brevis (I) bound the hollow of the anatomic snuff-box (arrow) anteriorly, and the extensor pollicis longus (III) bounds it
posteriorly. Observe the tendons of the fourth compartment (arrowheads) which diverge as they proceed distally over the dorsal
hand. c Photograph of the ventral lateral aspect of the wrist shows the position of the abductor pollicis longus and extensor pollicis
brevis tendons (open arrow) relative to the anatomic snuff-box (asterisk) and the radial styloid (R). The flexor carpi radialis (white
arrow) and palmaris longus (arrowhead) tendons are also delineated on a more ventral location. Note the pisiform bone (P)
Wrist
EDC
EPL
U
a
b
10.2.2.2
Flexor Tendons
At the volar aspect of the wrist, nine flexor tendons
enter the carpal tunnel to reach the fingers. There are
four tendons from the flexor digitorum superficialis
for the second through fifth fingers, four from the
flexor digitorum profundus for the same fingers and
the flexor pollicis longus tendon.
The flexor digitorum superficialis muscle gives
rise to four tendons at the distal radius, just cranial to
the proximal edge of the transverse carpal ligament.
Then, these tendons pass within the carpal tunnel to
diverge toward the fingers. During active finger movements, tendons of the flexor digitorum superficialis
can be palpated at the wrist between the prominences
of the flexor carpi radialis and ulnaris tendons. The
four tendons of the flexor digitorum profundus traverse the wrist just deep to the respective tendons of
the flexor digitorum superficialis. In the carpal tunnel,
the tendon of the index finger is separate whereas the
remaining tendons to the third through fifth fingers
may become completely independent only in the
palm. The lumbrical muscles arise in the palm from
the tendons of the flexor digitorum profundus. The
tendon of the flexor pollicis longus lies deep to the
flexor carpi radialis in the distal forearm and passes
on the radial side of the flexor digitorum tendons of
the index finger in the carpal tunnel. On approaching
the wrist, the tendons of the flexor digitorum superficialis and profundus become enveloped by a common
synovial sheath. On transverse views, this sheath is
“ε” shaped with a superficial extension which lies in
front of the flexor digitorum superficialis, a middle
extension lying between the flexor digitorum superfi-
Fig. 10.4 a,b. Anatomy of the extensor tendons. a Schematic drawing
of a coronal view of the dorsal wrist
showing the relation among tendons
of the fourth, fifth and sixth compartments. In the fourth compartment,
the extensor indicis proprius (intermediate gray) runs together with the
extensor digitorum (black). b Photograph of the dorsal wrist in a young
woman during forced wrist dorsiflexion demonstrates the diverging tendons of the extensor digitorum (EDC)
over the skin. Other surface landmarks include the skin depression of
the anatomic snuff-box (arrow), the
extensor pollicis longus tendon (EPL)
and the head of the ulna (U)
cialis and profundus and a deep extension behind the
flexor profundus. Just radial to the common flexor
tendon sheath, the flexor pollicis longus tendon is
enveloped by a separate sheath.
The primary flexors of the wrist, the flexor carpi
radialis and the flexor carpi ulnaris, course outside
the carpal tunnel and are readily palpable because
they lie in a more superficial position than the flexor
digitorum tendons (Fig. 10.5). The flexor carpi radialis
tendon is a long flattened tendon which becomes oval
in shape as it approaches the wrist. This tendon originates nearly midway between the elbow and wrist, is
invested by an own synovial sheath and inserts on
the palmar aspect of the base of the second metacarpal after coursing in a separate fibrous tunnel (vertical groove) made by an extension of the transverse
carpal ligament. Its action allows flexion and concurrent radial deviation of the wrist. The flexor carpi
ulnaris, the only tendon of the wrist not invested by
a synovial sheath together with the palmaris longus
tendon, is smaller in size and shorter relative to the
flexor carpi radialis. This tendon courses on the ulnar
side of the wrist housing the pisiform, which is considered a sesamoid bone in it, and inserts on the hook
of the hamate (piso-hamate ligament) and on the fifth
metacarpal (piso-metacarpal ligament). The flexor
carpi ulnaris tendon is a landmark for the adjacent
ulnar artery and nerve, both located just radial to
them. Its action allows flexion and concurrent ulnar
deviation of the wrist, an essential action in some
tasks such as using a screwdriver or a mallet.
The palmaris longus tendon is a long thin tendon
which passes in the midline and superficial to the
transverse carpal ligament (Fig. 10.5). Distally, it
splits into diverging bundles which intermingle with
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S. Bianchi and C. Martinoli
P
0
A
a
-.
b
the transverse carpal ligament and the palmar aponeurosis. It is absent in approximately 20% of individuals.
10.2.3
Neurovascular Structures
The wrist is crossed by the median nerve, the ulnar
nerve and the superficial cutaneous branch of the
radial nerve. In the wrist area, the ulnar nerve is
accompanied by the ulnar artery and the median
nerve gives off a sensory branch, the palmar cutaneous branch.
Fig. 10.5 a,b. a Photograph of the anterior
aspect of the wrist with b cadaveric correlation shows the flexor carpi radialis
tendon (black arrow) which serves as a
guide to the radial artery (a) which lies
just lateral to it. The long lean tendon
of the palmaris longus (arrowhead) is
a landmark for the median nerve (MN)
which is deep and frequently lateral to
it. More medially, the flexor carpi ulnaris tendon (open arrow) is seen moving
down to the pisiform (P). This tendon
may be used as a key reference for the
ulnar artery and nerve which lie lateral
to it
Throughout the carpal tunnel, the median nerve is
covered by a strong fibrous band commonly referred
to as the transverse carpal ligament or the flexor retinaculum (Fig. 10.6a,b). This is a localized thickening
of the fascia that inserts on the tubercle of the scaphoid and trapezium (radial side) and on the pisiform
and hook of the hamate (ulnar side) (Fig. 10.7). The
median nerve provides sensory supply to the palmar
aspect of the first three fingers and the radial half
of the fourth, and motor supply for the muscles of
the thenar eminence. Just proximal to the transverse
carpal ligament, the median nerve sends a palmar
cutaneous branch, which is a sensory nerve that supplies the radial half of the palm. This latter branch is
very small and typically vulnerable to injury during
carpal tunnel release.
10.2.3.1
Median Nerve
At the distal forearm, the median nerve courses in the
fascial plane intervening between the flexor digitorum profundus and the flexor digitorum superficialis
muscles. As the nerve approaches the wrist, it shifts
radially and then moves superficially along the lateral
margin of the flexor digitorum superficialis to align
itself with the midline before entering the carpal
tunnel (Fig. 10.6). Inside the tunnel, the median
nerve runs superficial to the tendons of the flexor
pollicis longus and the flexor digitorum superficialis
for the second finger although its position may vary
somewhat depending on wrist position. The nerve
has an oval cross-section at the proximal tunnel and
tends to become more flattened as it progresses distally through the tunnel (level of the hamate hook).
10.2.3.2
Ulnar Nerve
In the distal forearm, the ulnar nerve lies on the
radial side of the flexor carpi ulnaris and on the ulnar
side of the ulnar artery. Here, it gives off two small
branches: the palmar and dorsal cutaneous branches.
More distally, the ulnar nerve pierces the deep fascia
to continue in the wrist superficial to the transverse carpal ligament throughout the Guyon tunnel
(Fig. 10.8). This small tunnel lies in a more superficial
and medial location relative to the carpal tunnel. It is
bounded by the pisiform medially (proximal tunnel),
the hook of the hamate laterally (distal tunnel), the
transverse carpal ligament (floor) and the palmar
carpal ligament (roof). The Guyon tunnel contains
432
S. Bianchi and C. Martinoli
(
Pisiform
Pisiform
a
(
Carpal
Carpal
Carpal
tunnel
Tunnel
Tunnel
a
A
DE
b
0
d
BC
✟
Ss
d
D
Carpal
Carpal
tunnel
tunnel
(
s
∗
d
Hamate
Hamate
FCU
a
c
e
Fig. 10.8 a−e. Guyon tunnel anatomy. a Ventral view of the wrist bones illustrates the course of the ulnar artery and the ulnar nerve
in the Guyon tunnel relative to the flexor carpi ulnaris tendon (fcu), the pisiform (P) and the hook of the hamate (H). The transverse
carpal ligament (arrowheads) forms the floor of the Guyon tunnel. In the distal portion of the tunnel, the ulnar nerve divides into
a superficial sensory branch (straight arrow) and a deep motor branch (curved arrow). b,c Gross anatomic views with d,e corresponding diagrams of the proximal (b,d) and distal (c,e) Guyon tunnel obtained at the levels (horizontal white bars) indicated in
a show the main trunk of the ulnar nerve (void arrow) and its divisions, deep (d) and superficial (s). Close to the nerve, the ulnar
artery (a) bifurcates in the respective deep (asterisk) and superficial (star) branches. In d, observe the position of the ulnar nerve
relative to the pisiform, the transverse carpal ligament (black arrow) and the palmar carpal ligament (arrowheads)
the ulnar nerve (medial) and the ulnar artery (lateral) and veins embedded in fatty tissue. The ulnar
nerve bifurcates within this tunnel into two terminal
divisions – the superficial sensory branch and the
deep motor branch – the latter supplying most of the
intrinsic muscles of the hand, including the hypothenar muscles, the two medial lumbrical muscles, the
adductor pollicis and the interosseous muscles. The
ulnar nerve gives sensory supply to the medial aspect
of the palm, the little finger and the medial half of the
ring finger. Distal to the Guyon tunnel, the superficial
branch has a straight course while the deep motor
branch reflects across the palm to end at the first
interosseous space (Fig. 10.8a).
10.2.3.3
Radial Nerve (Cutaneous Terminal Branch)
At the distal radial aspect of the forearm, the superficial cutaneous branch of the radial nerve emerges
between the tendons of the extensor carpi radialis
longus and the brachioradialis to reach the subcutaneous tissue. At this point, the nerve is covered by a
fascial band which connects the tendon and myotendinous junction of the brachioradialis muscle with
the tendon of the extensor carpi radialis longus. More
distally, the radial nerve pierces the fascia and overlies the anatomic snuff-box traversing the extensor
tendons of the first compartment to provide sensory
supply to the dorsum of the wrist, hand, thumb and
proximal portion of the radial fingers.
10.2.3.4
Radial and Ulnar Arteries
The brachial artery has two terminal branches: the
radial artery and the ulnar artery. At the distal forearm,
the radial artery courses superficially over the ventral
aspect of the distal radius where its pulse can readily
be felt. Then, it curves dorsally over the radial aspect
of the wrist, passes deep to the extensor tendons of the
first compartment and crosses the floor of the anatomic
Wrist
snuff-box. The ulnar artery enters the wrist on the lateral side of the ulnar nerve and runs together with the
nerve throughout the Guyon tunnel, superficial to the
transverse carpal ligament (Fig. 10.8). Somewhat similar to the nerve, the ulnar artery splits into a superficial
palmar branch and a deep palmar branch.
10.3
Essentials of Clinical History and Physical
Examination
Before US examination, the patient’s history should
be carefully investigated to rule out any possible
systemic articular disorder (rheumatoid arthritis
and similar conditions), sporting or occupational
activities possibly related to tendinitis and overuse
syndromes, as well as local trauma (occult fractures,
tendon ruptures, ligament sprains). At physical examination, the range of wrist movements (flexion-extension, ulnar-radial deviation, pronation-supination)
can readily be assessed. An accurate location of the
site of pain may be helpful in the case of tendinitis.
In addition, movements that cause pain should also
be tested. Recent standard radiographs, if any, should
be reviewed for signs of joint and bones disease (i.e.,
osteoporosis, marginal erosions, focal bone lesions),
abnormal position of bones (reflecting ligaments
tears) and soft-tissue thickening and calcifications.
When a space-occupying mass is encountered over
the dorsal or palmar aspects of the wrist, intermittent
variations in its size with time can suggest the diagnosis of a ganglion cyst. When the mass is linked to
an adjacent tendon and follows it during movements,
an intratendinous ganglion should be suspected.
a
10.3.1
De Quervain Disease
In de Quervain disease, an inflammatory disorder
affecting the first compartment of the extensor tendons, patients report tenderness and pain over the
radial styloid. Typically, the wrist pain increases
during grasping heavy objects. A useful diagnostic
test is the Finkelstein test (Fig. 10.9). During this
maneuver, the patient holds his or her thumb inside
the clenched fist while the examiner tilts the patient’s
hand in an ulnar direction to stretch the tendons of
the first compartment. The Finkelstein test indicates
de Quervain disease when it causes pain over the
radial styloid that resemble the one described by the
patient. Care should be taken, however, not to rely on
this finding alone, because the Finkelstein test can be
positive in normal subjects if the examiner applies
excessive tension and in cases of rizarthrosis and
radial styloiditis. As an alternative test, the examiner
can maximally abduct the patient’s thumb while keeping the wrist in radial deviation. This latter maneuver
is more specific because it pushes the tendons against
the retinaculum and not toward the bone, thus recalling the same stress forces that generate symptoms in
de Quervain disease. Both tests should be performed
by the examiner because they help to direct the US
examination to the first compartment.
10.3.2
Carpal Tunnel Syndrome
Patients with carpal tunnel syndrome typically complain of night tingling and burning pain over the
radial aspect of the hand and the first three fingers.
b
Fig. 10.9 a,b. Finkelstein test for evaluation of de Quervain disease. a Schematic drawing of a sagittal view through the wrist during
ulnar deviation outlines tension of the first compartment tendons resulting from stretching over the radial styloid. b The Finkelstein sign is performed as follows: while the patient adducts the thumb into the palm making a fist, the examiner tilts the wrist
in ulnar deviation (curved arrow) to stretch the tendons of the first compartment (arrowheads). A positive test causes localized
excruciating pain over the radial styloid
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S. Bianchi and C. Martinoli
The same symptoms can be felt during the day when
a fixed position of the hand grasping an object is
required, such as holding a heavy book or the telephone receiver. Because of the tingling, it is not
unusual for patients to refer findings of carpal tunnel
syndrome to a vascular disorder. Two clinical tests
can be helpful to establish the diagnosis: the Tinel
test and the Phalen test. The Tinel test is performed
by tapping the volar aspect of the carpal tunnel with
a reflex hammer (Fig. 10.10a), while, in the Phalen
test, a full flexed wrist position is maintained for 1
min (Fig. 10.10b).Both tests are positive if they reproduce the patient’s symptoms. The examiner should
be aware, however, that false negatives may occur in
cases of chronic entrapment disease.
10.4
US Scanning Technique and
Normal US Anatomy
The patient is asked to sit comfortably in front of
the examiner with both wrists and elbows resting on the examination table. Aged or traumatized
patients may lie supine with the arm resting at
the side of the body, although examination of the
opposite side may become problematic in this position. For dynamic scanning of the extensor tendons, the hand is best placed on a gel tube with
the fingers hanging over its edge to make fingers
movements easier.
The routine US examination of the wrist begins
with evaluation of its dorsal aspect, followed by the
palmar one. Depending on the specific clinical presentation, US images can be obtained in different
a
positions of the wrist (flexion and extension, radial
and ulnar deviation, pronation and supination). Evaluation of gliding of the flexor and extensor tendons
must always be performed during passive and active
movements of the fingers.
10.4.1
Dorsal Wrist
Transverse US images are the best for detection
and a proper identification of the extensor tendons.
Assessment of the individual tendons is based on
their anatomic position and behavior at dynamic
examination (Lee anh Healy 2005). Detection of
the extensor tendon for the third finger, for instance,
is straightforward when transverse US scans are
obtained during active flexion and extension of
this finger while the others are maintained fixed
by the examiner. On the other side, the extensor
carpi radialis and the extensor carpi ulnaris are not
affected by fingers movements and can be distinguished only on the basis of their anatomic position.
US images are first obtained at the level of the distal
epiphysis of the radius. The most useful landmark
at this level is the Lister tubercle. This appears as
a hyperechoic bony prominence over the dorsal
surface of the radius. The tubercle separates the
medial third compartment from the lateral second
compartment (Fig. 10.2c). The extensor tendons
appear as oval or rounded hyperechoic structures
of different size. The extensor carpi radialis brevis
and longus are the largest while the extensor pollicis
longus and the extensor digiti quinti are the smallest. With high-resolution transducers, the extensor
retinaculum appears as a thin transversely oriented
b
Fig. 10.10 a,b. Clinical tests for evaluation of carpal tunnel syndrome. a The Tinel sign elicits paresthesias by tapping the median
nerve at the palmar crease. b The Phalen sign provokes paresthesias at the end of the range of flexion of the wrist
Wrist
fcr
fcr
a
fds
fds
fpl
fpl
∗
Radius
Radius
MN
fdp
fdp
∗
Ulna
Ulna
a
fds
fds
fcu
fcu
fdp
fdp
∗
∗
fcu
FCU
UN
FDS
fds
fcr
FCR
Ulna
Ulna
Radius
Radius
b
c
Fig. 10.23 a−c. Ventral wrist structures proximal to the carpal tunnel. Transverse 12−5 MHz US images obtained over the a radial
and b ulnar sides of the proximal wrist (level of radial and ulnar metaphyses) demonstrate the relationship among ventral
tendons, nerves and vessels proceeding toward the wrist over the pronator quadratus (asterisks). From lateral to medial, these
structures are: the radial artery (a), the flexor carpi radialis (fcr) and flexor pollicis longus (fpl), the median nerve (MN), the
flexor digitorum superficialis (fds) and flexor digitorum profundus (fdp), the ulnar artery (white arrow), the ulnar nerve (UN)
and the flexor carpi ulnaris (fcu). In a, observe the palmaris longus tendon as a very superficial and thin hypoechoic band
(open arrow) lying medial to the flexor carpi radialis. c Gross anatomic view of the ventral wrist shows the relationship of the
palmaris longus (arrows) with the flexor carpi radialis (fcr), the flexor digitorum superficialis (fds) and the flexor carpi ulnaris
(fcu) tendons. The inserts at the upper left side of the figure indicate probe positioning
a more medial location. Anatomic variations in the
number of wrist arteries can be found. The presence
of a median artery of the forearm, close to the median
nerve, can be readily assessed with US. When evaluating wrist vessels, care should be taken not to apply
excessive pressure with the transducer on the artery
to avoid its collapse and non-visualization.
Proximal to the carpal and Guyon tunnels, the
median and ulnar nerves are recognized based on
their peculiar fascicular echotexture. Approaching
the wrist, the median nerve becomes more superficial and lateral and then runs toward midline
and in a deeper position to enter the carpal tunnel
(Jamadar et al. 2001). The palmar cutaneous branch
of the median nerve arises from its palmar-radial
quadrant approximately 5 cm cranial to the proximal
wrist crease (Taleisnik 1973). It remains bound at
the main nerve trunk to leave it after approximately
2 cm (Fig. 10.25). After piercing the antebrachial
fascia or the transverse carpal ligament and entering the palm, the palmar cutaneous branch of the
median nerve supplies the skin of the thenar and
midpalmar areas. Awareness of the palmar cutaneous branch is important from the surgical point of
vies to avoid inadvertent resection during release of
the transverse carpal ligament performed with a too
radial approach. Injury of this branch is followed by
postoperative sensory disturbances. On short axis
planes high-resolution US transducers can image
this small nerve division. The ulnar nerve is found
at the medial aspect of the distal forearm between
the tendon of the flexor carpi ulnaris and the ulnar
artery. Because of its close relationship with the
ulnar artery, the ulnar nerve can be easily identified
by detecting the pulsatility or the presence of color
flow signals in the adjacent artery.
443
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S. Bianchi and C. Martinoli
pq
c
a b
Scaphoid
Radius
d
a
Radius
b
MN
Pisiform
ft
MN
ft
c
d
Fig. 10.24 a−d. Longitudinal scanning planes over the ventral wrist obtained with a 12−5 MHz US transducer demonstrate
from lateral (a) to medial (d) according to the reference diagram shown at the upper left side of the figure: a, the course of the
radial artery (arrowheads), which is superficial between the skin and the pronator quadratus (pq) and then deepens to enter
the anatomic snuff-box; b, the diverging course of the flexor carpi radialis (arrowhead) and flexor pollicis longus (arrow) over
the scaphoid bone; c, the superficial course of the median nerve (MN) relative to the flexor tendons (ft) in the carpal tunnel
and d, the flexor carpi ulnaris tendon (arrowhead) which courses superficial to the pisiform
fcr
b
b
a
a
a
c
fcr
FCR
b
d
Fig.10.25 a−d. Palmar cutaneous branch of the median nerve. a Schematic drawing of a coronal view through the lateral wrist
and b corresponding gross anatomic specimen outline the course of the median nerve (arrows) and its palmar cutaneous branch
(arrowheads) relative to the flexor carpi radialis tendon (fcr) and the transverse carpal ligament. c,d Transverse 15−7 MHz US
images obtained c at the distal radius and d at the proximal carpal tunnel level reveal the palmar cutaneous branch as a small
hypoechoic fascicle (straight arrow) which leaves the median nerve (curved arrow) and pierces the transverse carpal ligament
(arrowheads) to run between it and the flexor carpi radialis tendon (fcr)
Wrist
verse carpal ligament which holds the flexor carpi
radialis tendon. The nine flexor tendons (four from
the flexor digitorum superficialis, four from the flexor
digitorum profundus and the flexor pollicis longus)
can be imaged inside the carpal tunnel as individual
structures (Fig. 10.26). The identification of each of
these tendons is easily accomplished based on their
anatomic position (radial flexors rest on the radial
side of the tunnel, ulnar flexors on the ulnar side)
and by their action at dynamic US scanning. Compared with the round cross-sectional profile of the
flexor digitorum tendons, the flexor pollicis longus
is more oval in shape and its major axis is vertically oriented on transverse planes. At least in part,
this may depend on the course of this tendon which
diverges radially to reach the thumb. The median
nerve courses superficial and parallel to the second
and third flexor tendons and medial to the flexor
pollicis longus tendon, just deep to the transverse
carpal ligament (Fig. 10.26). Its cross-section is usually an ellipse, but its shape may change depending
on wrist positions and varies among subjects (Kuo
et al. 2001). In addition, even the size of the nerve
seems to change relative to the wrist activity (MassyWestropp et al. 2001). During flexion of the fingers
or fist clenching, transverse US images demonstrate
passive shifting movements of the median nerve on
the underlying gliding flexor tendons (Nakamichi
and Takibana 1992).
Some anatomic variants of clinical relevance
in the intracanal structures can be identified with
US. The presence of anomalous muscles coursing
within the carpal tunnel has been reported, includ-
10.4.2.2
Proximal Carpal Tunnel
The most useful bony landmarks to identify the
proximal carpal tunnel are the pisiform at its ulnar
side and the scaphoid at its radial side (Fig. 10.7). At
US examination, these bones appear as round hyperechoic structures with posterior acoustic shadowing. Once these landmarks are demonstrated in a
single image, the orientation of the probe should be
adjusted to optimize the depiction of the soft tissues
contained within the tunnel (Fig. 10.26). Tilting the
probe back and forth may be helpful to distinguish the
hypoechoic median nerve by the adjacent anisotropic
tendons. Relative to the flexor carpi radialis, the flexor
pollicis longus tendon runs in a deeper location,
slightly closer to the midline. Oblique longitudinal
US images can depict these tendons in the same plane
(Fig. 10.24b). The proximal carpal tunnel is larger in
size compared with the distal tunnel. In a comparative US-cadaveric study, US has proved to be accurate
in evaluating the different diameters, the outline and
the cross-sectional area of the carpal tunnel and the
median nerve (Kamolz et al. 2001). The transverse
carpal ligament appears as a thin slightly convex
band of 1−1.5 mm thickness (Fig. 10.26). Its attachments to the pisiform and the scaphoid are readily
detected with US. Because of its curvilinear shape, the
anisotropic transverse carpal ligament may appear
hypoechoic when the US beam is not perpendicular
to it. This is particularly true at its attachments. Even
with a careful scanning technique, high-resolution
US is unable to depict the lateral division of the trans-
a
fcr
fcr
fpl
Sca
a
s
p
s
s
s
p
p
p
Pis
s
fpl
p
Sca
s
s
s
p
p
Pis
p
b
Fig. 10.26 a,b. Proximal carpal tunnel and Guyon tunnel. a Schematic drawing and b corresponding transverse 12−5 MHz US
image show the proximal level of the carpal tunnel delimited by the scaphoid (Sca) and the pisiform (Pis). The transverse carpal
ligament (arrowheads) forms the roof of the carpal tunnel and the floor of the Guyon tunnel. The palmar carpal ligament (light
gray) forms the volar boundary of the Guyon tunnel. US image demonstrates the tendons of the flexor digitorum superficialis
(s) and profundus (p), the tendons of the flexor pollicis longus (fpl) and flexor carpi radialis (fcr) and the median nerve (straight
arrow) extending through the carpal tunnel, with the nerve lying palmar-radially. At the pisiform level, the ulnar nerve (curved
arrow) courses medial to the ulnar artery (a) within the Guyon tunnel
445
Wrist
fcr
fpl
Sca
s
s
s s
p
p
p p
Pis
a
b
d
c
e
Fig. 10.28 a−e. Persistent median artery of the forearm and bifid median nerve. a Schematic drawing in the axial plane and b
gross anatomic coronal view of the carpal tunnel outline the course of a persistent median artery (arrowheads) interposed
between the two trunks (arrows) of a bifid median nerve. c Transverse 12−5 MHz US image obtained at the middle forearm
show the relationship of the persistent median artery (arrowhead) with the median nerve (arrow). Observe that the median
nerve is not yet divided at mid-forearm level. Transverse d gray-scale and e color Doppler 12−5 MHz US images obtained at
the proximal carpal tunnel level of the same case shown in c demonstrate the median artery (arrowhead) located between
the radial and ulnar trunks (arrows) of a bifid median nerve. Note that the two nerve trunks and the artery are enveloped by
a common epineurium. The patient had mild intermittent symptoms related to carpal tunnel syndrome. Sca, scaphoid; Pis,
pisiform; fcr, tendons of the flexor carpi radialis; fpl, flexor pollicis longus tendon; p and s, tendons of the flexor digitorum
superficialis and profundus
Fig. 10.29. Persistent median artery of the forearm.
Transverse gray-scale 12−5 MHz US image of the
proximal carpal tunnel in an asymptomatic subject
reveals a persistent median artery (arrowhead) on
the ulnar side of the median nerve (arrows). Note
the anechoic appearance of the artery relative to
the hypoechoic nerve fascicles. In the insert at the
lower right side of the figure color Doppler imaging demonstrates flow signals inside the vessel
447
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S. Bianchi and C. Martinoli
a
✟
★
fpl
s
s
s s
p
p
p
Tra
p
∗
✟
★
Ham
fcr
fpl
p
Tra
a
s
s
p
s s
p
p
∗
Ham
b
Fig. 10.30 a,b. Distal carpal tunnel. a Schematic drawing and b corresponding transverse 12−5 MHz US image show the distal
level of the carpal tunnel delimited by the trapezium (Tra) and the hamate (Ham). The transverse carpal ligament (open arrowheads) inserts on the tubercle (star) of trapezium and the hook (asterisk) of the hamate. US image demonstrates the tendons of
the flexor digitorum superficialis (s) and profundus (p), the tendons of the flexor pollicis longus (fpl) and flexor carpi radialis
(white arrowhead in a, fcr in b) and the median nerve (open arrow). At the hamate level, the transverse carpal ligament is thicker
than at the proximal carpal tunnel (see for comparison Fig. 10.26b) and the ulnar nerve divides into two terminal branches: a
deep motor (curved arrow) and a superficial sensory (straight white arrow) branch. a, ulnar artery
1
22
3
-.
flexor
tendons
a
b
Fig. 10.31a,b. Median nerve beyond the carpal tunnel. a Transverse 12−5 MHz US image obtained beyond the distal edge of the
transverse carpal ligament with b gross anatomic correlation reveals the division of the main trunk of the median nerve (MN)
into three branches (1, 2, 3), the common palmar digital nerves
10.4.2.4
Guyon Tunnel
The Guyon tunnel is located in a medial and superficial position relative to the carpal tunnel. It is
delimited by the dorsal aspect of the transverse
carpal ligament and the superficial palmar carpal
ligament on the radial side, and by the lateral aspect
of the pisiform on the ulnar side. The transverse
carpal ligament and the pisiform are easily detected
with US. On the contrary, the superficial palmar
carpal ligament is very thin and difficult to visualize. Once the curvilinear shape of the pisiform is
found, care should be taken to identify the ulnar
artery as a round, pulsatile hypoechoic structure.
The ulnar nerve lies in between these two structures
and can be better depicted by means of subtle tilting movements of the probe. It appears as a small
structure of 2−2.5 mm in size, containing a few
internal hypoechoic fascicles (Fig. 10.32a,b). The
most commonly encountered anomalous muscle in
the tunnel is the accessory abductor digiti minimi
(Timins 1999) (see Sect. 10.5.4.4). Distal to the pisiform, the distal Guyon tunnel can be imaged with
very high-resolution transducers. At this level, the
ulnar nerve can be seen dividing into two terminal
branches: the superficial sensory branch continues
to run close to the ulnar artery, whereas the deep
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S. Bianchi and C. Martinoli
E
A
C
D
G
F
B
a
b
Fig. 10.33 a,b. Schematic drawings illustrate typical sites of overuse tendinopathies in the a dorsal and b ventral wrist, including:
A, de Quervain tenosynovitis; B, intersection syndrome; C, extensor pollicis longus tenosynovitis, D, extensor carpi ulnaris tenosynovitis; E, flexor carpi radialis tenosynovitis; F, flexor digitorum superficialis and flexor digitorum profundus tenosynovitis;
G, flexor carpi ulnaris tendinopathy
abduction of the thumb against resistance, such as
occur while holding the baby‘s head (Baby Wrist)
(Anderson et al. 2004). Low grade chronic microtrauma at the level of the radial styloid can lead to
localized thickening of the extensor retinaculum of
the wrist, narrowing of the first compartment of
the extensor tendons and subsequent impingement
and inflammation of the extensor pollicis brevis and
abductor pollicis longus tendons. Clinically, patients
complain of tenderness and pain over the radial styloid exacerbated by wide movements of the thumb
and forceful pinching of objects. As already described
in Sect. 10.3.1, a useful diagnostic test, the Finkelstein
test, is performed by applying passive ulnar deviation of the wrist with the thumb maximally flexed,
a maneuver that aggravates the patient’s pain. Treatment of de Quervain disease relies on anti-inflammatory drugs and splinting. Resistant cases are treated
with more invasive approaches such as local injections and surgical release of the retinaculum. A vertical septum splitting the first compartment seems to
predispose to local tendon friction and is encountered more frequently in patients than in cadaver
surveys (Bahm et al. 1995). Several authors have
described the US appearance of de Quervain disease
(Gooding 1988; Marini et al. 1994; Nagaoka et
al. 2000; Trentanni et al. 1997; Giovagnorio et al.
1997). Both longitudinal and transverse US images
are performed over the radial styloid. Although lon-
gitudinal planes are more valuable during dynamic
scanning, transverse images give a better view of the
retinaculum, internal septa and accessory tendons.
The affected tendons are typically swollen and, as a
whole, they have a more rounded cross-section under
the retinaculum than in normal subjects (Figs. 10.34,
10.35). In acute phases, a synovial sheath effusion
surrounding the tendons can be demonstrated caudal
to the distal edge of the retinaculum, whereas in
chronic longstanding disease the extensor tendons
may appear hypoechoic or may have a heterogeneous
echotexture. A thickened and hypoechoic extensor
retinaculum should be accurately searched for at
US because its demonstration can indicate the need
for surgical decompression. Accessory vertical septa
appear as thin vertical hypoechoic bands intervening
between the tendons (Nagaoka et al. 2000). Demonstration of a vertical septum has clinical implications
because it acts as a barrier to diffusion of injected steroids and requires opening of both tunnels at surgery
(Leslie et al. 1990). In some cases, the inflammatory
process may selectively involve one tendon when a
septum is present (Fig. 10.36). In a postoperative setting, high-resolution US can identify complications,
such as the volar subluxation of tendons due to an
excessive section of the retinaculum (Fig. 10.37). In
conclusion, although the clinical diagnosis of de
Quervain tenosynovitis is not difficult, US can help
to confirm it, detect whether a vertical septum is
Wrist
APL
APL
EPB
EPB
Radius
Radius
a
b
c
Fig. 10.38 a−c. Wartenberg syndrome. a,b Short-axis and
c long-axis 15−7 MHz US images over the radial nerve at the
wrist in a patient with symptoms of superficial radial neuropathy after intravenous infusion in the cephalic vein. a Proximal to the level of injury, a normal-appearing nerve (arrow)
is seen adjacent to an occluded cephalic vein (arrowhead).
b,c At the level of puncture, a fusiform hypoechoic thickening
of the nerve (arrow) with loss of the fascicular echotexture
can be appreciated as a result of trauma. Note the position of
the nerve relative to the abductor pollicis longus (APL) and
extensor pollicis brevis (EPB) tendons
APL
Radius
radialis longus and the extensor carpi radialis brevis
– at the level at which they are crossed by the abductor pollicis longus and extensor pollicis brevis. This
condition is usually secondary to occupational repetitive flexions and extensions of the wrist, such as
occur in rowers and weightlifters. The clinical diagnosis is not straightforward because intersection syndrome may be easily confused with the more distal
de Quervain disease. Wrist splints and local steroid
injections are curative in most patients. Intersection
syndrome appears at US as an ill-defined hypoechoic
area between the two tendon groups, probably corresponding to local soft-tissue edema and tenosynovial fluid, with loss of the hyperechoic cleavage plane
between them (Fig. 10.39). A true synovial bursa filled
by fluid is a rare finding.
10.5.1.4
Extensor Pollicis Longus Tenosynovitis
As already stated, the extensor pollicis longus tendon
(third compartment of the extensor tendons) is a
thin tendon that reflects over the medial aspect of
the Lister tubercle before reaching the dorsum of the
hand. Because of mechanical friction and its small
size, the extensor pollicis longus is frequently affected
by tenosynovitis that presents with local pain over the
Lister tubercle and, less commonly, with local crepitus during thumb movements. This condition can be
associated with previous fractures of the distal radius
(Denman 1979) and leads to considerable tendon
weakness, partial and complete tears if untreated. In
extensor pollicis longus tenosynovitis, the synovial
sheath effusion is typically found just proximal to the
Lister tubercle and after the tendon has crossed the
extensor carpi radialis longus (Fig. 10.40). Due to the
restricted space under the fascia, the synovial sheath of
this tendon may be distended with fluid in the area of
the Lister tubercle and over the radial wrist extensors
only when the amount of effusion is remarkable.
10.5.1.5
Extensor Carpi Ulnaris Tenosynovitis
Extensor carpi ulnaris tenosynovitis is mostly
secondary to instability of the retinaculum of the
sixth compartment, as a result of mechanical friction
of this tendon against the ulna. The patient typically
complains of a localized pain over the dorsum of the
ulna. Clinical findings are nonspecific and can mimic
disorders of the distal radio-ulnar joint, especially
when a snapping sensation is present. Although highresolution US cannot accurately recognize distal
radio-ulnar joint pathology, it can readily measure
the tendon size, and is able to identify intrasubstance
longitudinal splits related to recurrent tendon subluxation and to evaluate tendon sheath effusion and
synovial hypertrophy (Figs. 10.41, 10.42). The relevance of a dynamic examination has to be emphasized in this setting.
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S. Bianchi and C. Martinoli
∗
a
∗
∗
c
∗
Radius
Radius
b
∗
Fig. 10.39 a−d. Intersection syndrome.
a−c Serial sequence of transverse
12−5 MHz US images obtained from
a cranial to c caudal over the distal
dorsal forearm demonstrate tenosynovial effusion (asterisks) in the sheath
of the extensor carpi radialis longus
and brevis at the level in which these
tendons are crossed (arrow) by the
muscle bellies of the abductor pollicis
longus and extensor pollicis brevis.
Note the loss of the hyperechoic fat
plane intervening between these two
tendon groups. See Fig. 10.15a for
comparison with normal findings.
d Photograph of the forearm and wrist
of the same patient shows soft-tissue
swelling (arrows) at the radial aspect
of the distal dorsal forearm
Radius
Radius
∗
Radius
Radius
d
EPL
ECRB
EDC
Radius
b
A
ECRB
EPL
EDC
ECRL
B
Radius
c
C
a
∗
∗
d
EPL
ECRL
Scaphoid
Fig. 10.40 a−d. Extensor pollicis longus tenosynovitis. a Dorsal aspect of the wrist bones illustrates the course of the extensor
pollicis longus tendon (arrowheads) relative to the Lister tubercle (arrow) and the typical clepsydra-like distribution of sheath
fluid (asterisks) in a case of tenosynovitis. The narrow tunnel of the third compartment intrinsically hinders the sheath distension of the extensor pollicis longus at the level of the Lister tubercle except in cases of abundant effusion. Most often, the
fluid distributes just proximal to the Lister tubercle and after the tendon has crossed the extensor carpi radialis longus.
b−d Transverse 15−7 MHz US images over the third compartment of the extensor tendons obtained at the levels (horizontal white
bars) indicated in a show the typical distribution of fluid (asterisk) in the sheath of the extensor pollicis longus tendon (EPL) relative
to the Lister tubercle (arrow) and the extensor carpi radialis brevis (ECRB) and longus (ECRL). EDC, extensor digitorum tendons
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S. Bianchi and C. Martinoli
head, and may lead to stripping of the retinaculum. Tear of the retinaculum related to rheumatoid
arthritis will be discussed later (see Sect. 10.5.3.2),
because this finding is closely related to the involvement of the distal radio-ulnar joint and the extensor carpi ulnaris tendon sheath. Regardless of the
cause of retinaculum tear, the extensor carpi ulnaris tendon undergoes anterior (volar) dislocation.
The instability of the extensor carpi ulnaris may
result in either subluxation, when the flattened
tendon moves over the medial aspect of the ulna, or
intermittent dislocation, when there may be either
spontaneous phases of dislocation and reduction,
or permanent dislocations. Because of its highresolution capabilities and dynamic scanning, US
is the ideal imaging tool to confirm the instability
of the extensor carpi ulnaris tendon (Fig. 10.43).
Permanent dislocation of the extensor carpi ulnaris tendon is uncommon and can be identified by
means of transverse planes obtained over the posteromedial aspect of the ulna. The diagnosis of
intermittent dislocation is difficult if this possibility is not kept in mind by the examiner. To avoid
10.5.2
Ventral Wrist Pathology
Similar to the dorsal wrist, tendinopathies of the
flexor tendons are commonly encountered, most
often at the insertion of the flexor carpi radialis
tendon and within the carpal tunnel for the flexor
digitorum tendons (Fig. 10.33b) (Daenen et al. 2004).
In addition to tendinopathies, compression neuropathy of the median nerve at the carpal tunnel is the
leading pathology of the wrist as regards prevalence
of disease and clinical relevance. The entrapment of
the ulnar nerve at the Guyon tunnel is rare and, in
many cases, secondary to other disorders.
Ulna
Ulna
a
false negative results, care should be taken not to
limit the US examination to the static assessment
of the tendon. On the contrary, transverse planes
obtained during progressive pronation of the forearm can disclose the progressive displacement of
the extensor carpi ulnaris tendon over the ulnar
head.
c
e
A
B
Ulna
b
d
Ulna
f
Fig. 10.43 a−f. Extensor carpi ulnaris instability. a−d Dorsal transverse 12−5 MHz US images obtained over the distal epiphysis
of the ulna during progressive pronation of the forearm. a When the wrist is supinated, US shows the groove on the ulnar
cortex (open arrowheads) for the extensor carpi ulnaris tendon (arrow) and an irregular appearance of the retinaculum (white
arrowhead). b,c During progressive pronation, the extensor carpi ulnaris tendon (open arrow) subluxes (curved arrow) over
the internal wall of the groove. Note the flattened appearance of the tendon as a result of tensile forces applied on it. d In full
pronation, the extensor carpi ulnaris (arrow) dislocates out of the groove and exhibits a more rounded appearance. e,f Schematic drawings of a transverse view through the ulnar head e in the normal state and f when the retinaculum is torn. In e, the
intact retinaculum (1) maintains the extensor carpi ulnaris (2) within the osteofibrous tunnel. 3, styloid process of the ulna;
4, triangular fibrocartilage. In f, the retinaculum tear leads the extensor carpi ulnaris first to sublux (A) and then to dislocate
(B) out of the groove
Wrist
10.5.2.1
Flexor Carpi Radialis Tenosynovitis
At the proximal wrist, the flexor carpi radialis tendon is
held inside a splitting of the transverse carpal ligament
bounded posteriorly by the scapho-trapezium-trapezoid joint. More distally, the tendon passes below the
tubercle of the trapezium to become deep and insert
onto the base of the second metacarpal. Although flexor
carpi radialis tenosynovitis was only recently described
(Fitton et al. 1968; Parellada et al. 2006), this condition is not widely recognized. Middle-aged women are
most frequently affected. They report pain over the
radial aspect of the volar wrist and a local lump, often
misinterpreted as a volar ganglion. As an additional
finding, tingling on the skin of the thenar eminence
can be observed due to the close relationship of this
tendon with the palmar branch of the median nerve
(Kerboull and Le viet 1995). Pathogenesis includes
friction inside the carpal tunnel where the tendon curves
to reach its posterior insertion and osteoarthritis of
the first carpometacarpal joint and scapho-trapezium
joint, which are considered the leading causes (Le Viet
1995). In this latter circumstance, tendon inflammation is secondary to the presence of volar osteophytes
that cause impingement over the posterior aspect of
the tendon during flexion and extension movements
of the wrist. Surgery is only indicated if conservative treatment fails. In most cases, US examination is
a
c
10.5.2.2
Flexor Carpi Ulnaris Tendinopathy
With the exception of the palmaris longus, the flexor
carpi ulnaris is the only wrist tendon without a synovial
sheath because of its straight course from the forearm to the distal insertion into the pisiform. The term
“tendinopathy” is the most appropriate to describe this
condition, because fluid cannot be demonstrated surrounding the tendon even in acute clinical settings.
The most common disorder affecting the flexor carpi
ulnaris tendon is calcifying tendinitis. This disorder
predominantly affects young to middle-aged women,
presenting with pain located just proximal to the
pisiform. In general, the onset of pain is acute and
physical examination shows a tender pisiform covered
by inflamed warm skin. Symptoms are related to the
rupture of intratendinous calcified deposits into the
surrounding tissues with secondary acute inflamma-
b
e
fcr
fcr
Trapezium
requested to rule out a volar ganglion because of a
local swelling (see paragraph Sect. 10.5.4.1). The main
US signs include a swollen and irregularly hypoechoic
tendon (Fig. 10.44). A synovial effusion can often be
found within the tendon sheath as an expression of
tenosynovitis (Fig. 10.45). In some cases, longitudinal
fissures can be encountered, especially arising from the
deep surface of the tendon.
Scaphoid
d
Fig. 10.44 a−e. Flexor carpi radialis tendinopathy. a Long-axis and b short-axis 12−5 MHz US images of the flexor carpi radialis
tendon (fcr) show a swollen hypoechoic tendon (arrowheads) and bony irregularities (curved arrow) at the scapho-trapezium
joint level suggestive of osteoarthritis. c Transverse Gd+T1w SE and d coronal T2w tSE MR images demonstrate hypervascular
synovium and mild distention of the sheath (arrowheads) of flexor carpi radialis. e Photograph of the same patient shows a
localized swelling (arrow) over the involved tendon, just proximal to the scaphoid. In this case, physical examination presumed
that the lump was a volar ganglion
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∗
∗
fcr
fcr
∗
a
∗
fcr
fcr
∗
MN
ft
ft
fpl
fpl
b
ft
ft
c
Fig. 10.45 a−c. Acute tenosynovitis of the flexor carpi radialis tendon. a Short-axis and (b) long-axis 12−5 MHz US images at
the wrist demonstrate abnormal distension of the sheath of flexor carpi radialis tendon (fcr) by abundant hypoechoic fluid
(asterisks), whereas the tendon echotexture is normal. Note the relationship of the flexor carpi radialis with the median nerve
(MN), the flexor digitorum (ft) and the flexor pollicis longus (fpl) tendons. c Photograph of the same patient shows the mass
effect (arrows) of tendon sheath effusion on the radial side of the ventral wrist
tion. Therapy includes anti-inflammatory drugs, ice
and immobilization. In cases of severe refractory pain,
a brief (1−3 days) course of intramuscular steroids can
be indicated. The diagnosis of flexor carpi ulnaris tendinopathy is based on clinical and radiological findings.
Standard radiographs obtained in anteroposterior and
lateral views can be negative, small calcifications being
easily masked by the pisiform. If th