M u s c u l o s k e l e t a l I m a g i n g • R ev i ew
Jacobson et al.
Ultrasound of the Groin
FOCUS ON:
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Musculoskeletal Imaging
Review
Jon A. Jacobson1
Viviane Khoury 2
Catherine J. Brandon1
Jacobson JA, Khoury V, Brandon CJ
Ultrasound of the Groin:
Techniques, Pathology, and Pitfalls
OBJECTIVE. In a patient with symptoms referable to the groin, there can be a number of
causes to consider and at times the cause of the symptoms is multifactorial. Although ultrasound can be effective in the evaluation of the groin, the depth and complexity of the anatomy
can be problematic. A protocol-driven approach for ultrasound evaluation of the groin will
help to ensure an accurate and comprehensive evaluation. This article summarizes the ultrasound technique and protocol for evaluation of the groin to include evaluation of the hip joint,
anterior hip musculature, the iliopsoas bursa, the inguinal lymph nodes, the pubic sym­phys­
eal region, and the inguinal region for hernias. Common pathologic conditions and pitfalls
related to ultrasound evaluation of the groin will be reviewed.
CONCLUSION. There are many potential pathologic conditions in a patient with groin
symptoms. Because symptoms may be multifactorial and history may be ambiguous or misleading, a protocol-driven evaluation with ultrasound is recommended. The hip joint is evaluated for effusion, synovitis, and labral abnormalities. The muscles and tendons, including the
common aponeurosis at the pubic symphysis, are evaluated for tendinosis and tears. Dynamic
evaluation should be considered to assess for snapping hip syndrome. Iliopsoas bursal distention and lymph node enlargement are other considerations. Last, inguinal region hernias
must be evaluated during the Valsalva maneuver and documented in two orthogonal planes to
avoid several important diagnostic pitfalls.
U
Keywords: groin, hernia, hip, joint, ultrasound
DOI:10.2214/AJR.15.14523
Received February 2, 2015; accepted after revision
April 15, 2015.
1
Department of Radiology, University of Michigan, 1500 E
Medical Center Dr, TC-2910L, Ann Arbor, MI 48109-0326.
Address correspondence to J. A. Jacobson
(jjacobsn@umich.edu).
2
Department of Radiology, University of Pennsylvania,
Philadelphia, PA.
Supplemental Data
Available online at www.ajronline.org.
AJR 2015; 205:513–523
0361–803X/15/2053–513
© American Roentgen Ray Society
AJR:205, September 2015
ltrasound has been used to effectively evaluate pathology of the
musculoskeletal system [1–3].
When an abnormality involves the
distal extremity, ultrasound can accurately
show anatomy and pathology in detail with the
benefit of directly correlating imaging and
physical examination findings [4]. Dynamic
evaluation of structures with muscle contraction, joint movement, or position change of the
patient may also add significant information
that may not be obtainable with static MRI [5].
In contrast to evaluation of the distal extremities, evaluation of the groin and hip can
be more problematic. The added depth of the
area being imaged results in lower resolution, and there is more complex anatomy. It
is often difficult to directly correlate imaging
findings with patient symptoms and the clinical presentation may be ambiguous. To ensure a comprehensive evaluation, one should
follow a specific protocol when performing
an ultrasound examination (Table 1).
The groin can be defined as the area at the
junction of the lower abdomen and the in-
ner thigh; therefore, ultrasound of the groin
should include evaluation of the hip joint,
anterior hip musculature, iliopsoas bursa, inguinal lymph nodes, pubic symphyseal region, and inguinal region for hernias. Dynamic evaluation is also an integral aspect
of a groin ultrasound examination. This article reviews a protocol-driven approach to the
ultrasound evaluation of the groin, showing
common pathologic conditions and discussing diagnostic pitfalls.
Ultrasound Equipment
Clinically available ultrasound units, both
portable and cart-based, with variable frequency transducers can be used to evaluate
the groin and hip. For an examination of a
thin individual, a linear transducer of greater than 10 MHz is effective. For larger patients, a curvilinear transducer of less than
10 MHz is often needed to evaluate the hip.
It is a misconception to presume that a curvilinear transducer must be used, but often it is
necessary. The objective is to use the highest
frequency transducer possible to achieve the
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Jacobson et al.
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highest resolution given the constraints of a
patient’s body habitus.
Hip Joint
Scanning Details
For ultrasound examination of the hip
joint, the transducer is placed in the sagittal
oblique plane long axis to the femoral neck.
The characteristic bone landmarks of the
femoral head and neck should be identified
(Fig. 1A). The femoral neck should be perpendicular to the sound beam to eliminate
anisotropy of the overlying joint capsule.
The hyperechoic fibrocartilage labrum is
also identified at the acetabulum. The transducer is then rotated 90° to evaluate the anterior hip in its short axis (Fig. 1B).
Anatomy
The hip joint is evaluated for joint-related abnormalities, such as a joint effusion, intraarticular bodies, and synovial disorders.
When evaluating for a joint effusion, one
should target the area over the anterior femoral neck. Normally, a hyperechoic layer measuring up to 7 mm is present, representing
the iliofemoral ligament and joint capsule
with its reflection [6] (Fig. 1A). If not imaged
perpendicular, this hyperechoic layer may
appear artifactually hypoechoic from anisotropy and may potentially simulate joint fluid. Regardless, the layer should measure less
than 7 mm if normal [7]. An additional pitfall relates to leg positioning: Internal rotation of the hip may cause the anterior joint
capsule to become convex anteriorly and to
potentially measure greater than 7 mm.
Joint Effusion
A joint effusion will appear as anechoic
distention of the joint capsule preferentially
around the femoral neck [6]. In the native hip,
evaluation of the anterior recess provides an
adequate evaluation for a joint effusion. It is a
misconception to believe that fluid may be present only posteriorly; some degree of fluid is always present anterior to the femoral neck in the
native hip with a joint effusion [8]. However,
in the setting of a hip arthroplasty, a joint effusion may be loculated, which warrants a more
thorough evaluation of the lateral and posterior
femoral neck. As an additional pitfall after arthroplasty, ultrasound can be inaccurate in the
diagnosis of a small joint effusion [9]. An extensive evaluation of all areas of the hip is warranted when evaluating for complications related to a hip arthroplasty, such as particle disease
and pseudotumor formation [10].
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TABLE 1: Ultrasound Scanning Protocol of the Groin
Anatomic Region and Structures
Pathology
Hip joint
Anterior recess
Effusion, infection, synovial hypertrophy
Labrum
Labral tear, paralabral cyst
Femur
Femoroacetabular impingement
Anterior hip musculature
Iliopsoas complex
Snapping hip syndrome
Rectus femoris
Tendinosis including calcific tendinosis
Sartorius
Tendon tear
Iliopsoas bursa
Distention, synovial hypertrophy, infection
Inguinal lymph nodes
Superficial and deep inguinal lymph nodes
Hyperplasia, inflammation, primary neoplasia, metastases
Pubic symphyseal region
Rectus abdominis
Common aponeurosis injury
Pubic symphysis
Adductor tendon tear or tendinosis
Adductor tendons
Fracture
Inguinal region hernias
Internal ring and inguinal canal
Indirect inguinal hernia
Hesselbach triangle
Direct inguinal hernia
Femoral canal
Femoral hernia
Synovial Hypertrophy
If a joint effusion is complex, the fluid may
appear hypoechoic rather than anechoic and
synovial hypertrophy should be considered.
For assistance in the differentiation of a joint
effusion from synovial hypertrophy, a lack of
compressibility and internal flow on color or
power Doppler imaging would indicate synovial hypertrophy; however, this distinction
may be difficult, and ultrasound-guided aspiration may be indicated. Because findings on
ultrasound cannot be used to exclude infection, joint aspiration, lavage and reaspiration,
and synovial biopsy should be considered in
patients with any distention of the joint capsule if there is concern for septic joint [11–13].
In addition to infection, other possible causes
of synovial hypertrophy include systemic inflammatory arthritis, pigmented villonodular
synovitis (Fig. 2), synovial chondromatosis,
and amyloid deposition [14].
Labrum
Although the posterior aspect of the labrum is difficult to visualize on ultrasound,
the anterior aspect, which is the most common site for labral tears, can be easily evaluated [15]. A hypoechoic or heterogeneous
labrum indicates degeneration, whereas a
more defined anechoic cleft indicates a labral
tear [16]. In the evaluation for a labral tear
with ultrasound, sensitivity, specificity, and
accuracy have been shown to be 82%, 60%,
and 75%, respectively [16]; therefore, MRI,
preferably MR arthrography, is indicated if
there is concern for labral abnormalities [16].
One cause for a labral tear is cam-type femoroacetabular impingement (FAI), in which
an abnormal osseous contour of the proximal
femur or abnormal femoral head-neck offset
can impinge on the acetabulum causing hyaline cartilage and labral injuries [17]. Although ultrasound can show an anterosuperior bony prominence and cam deformity of the
proximal femur associated with FAI, alpha
angles cannot be reliably measured and ultrasound is not recommended for FAI screening
[18]. Related to a labral tear, a paralabral cyst
may also be identified on ultrasound as a lobular anechoic or hypoechoic fluid collection in
contact with the labral tear [19] (Fig. 3). As a
potential pitfall, a paralabral cyst may be hypoechoic and difficult to delineate, although
the lobular appearance and associated labral
tear suggest the appropriate diagnosis.
Anterior Hip Musculature
Scanning Details
For evaluation of the anterior hip musculature, ultrasound scanning can begin over the
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Ultrasound of the Groin
femoral head and neck in the sagittal oblique
plane using bone landmarks for orientation (Fig. 1A). The transducer can then be
turned transverse to the body and centered
over the femoral head where the psoas major
tendon and iliopsoas complex can be identified (Fig. 1B). The transducer can then be
moved cephalad to the level of the ilium at
the anterior inferior iliac spine (AIIS) to visualize the individual components of the iliopsoas complex (Fig. 1C). The transducer
can be moved lateral at the level of the AIIS
so that the rectus femoris can be identified.
More cephalad, the sartorius origin can be
identified at the anterior superior iliac spine.
The anterior hip musculature can then be assessed in both the long and short axes.
fibers, and the medial iliacus becomes interposed between the psoas major tendon and
superior pubic ramus [23]. As the patient returns the leg to a straight position, there is a
normal reversal in the rotational gliding of
the psoas major around the medial iliacus
muscle fibers. In patients with the abnormal
condition, the medial component of the iliacus muscle becomes temporarily entrapped
between the psoas major tendon and superior pubic ramus [20]. As the iliacus muscle
abruptly moves lateral, the psoas major tendon also abruptly moves posterior and makes
contact with the superior pubic ramus [20].
This contact results in an abnormal snap,
which is perceived by the patient and felt
through the transducer.
Iliopsoas Complex
The iliopsoas complex is composed of several structures. In the transverse plane at the
AIIS, the psoas major tendon is visible with
its muscle component located medial [20]
(Fig. 1C). The psoas major tendon may be bifid with partial and complete splits [20]. Anterolateral to the psoas major tendon are the
medial and lateral muscle fibers of the iliacus
with an interposed fascial layer [20]. Inferior
to the AIIS, the ilioinfratrochanteric muscle
component is present lateral to the iliacus;
the rectus femoris is located directly lateral
and the sartorius anterior to the ilioinfratrochanteric muscle [20]. An additional muscle
component, composed of the inferior fibers
of the iliacus, is more difficult to visualize on
ultrasound [20]. More distally, an accessory
tendon from the medial iliacus fibers unites
with the psoas major tendon to form the iliopsoas tendon several centimeters proximal
to the lesser trochanter. The lateral aspect of
the iliacus attaches to the proximal femoral
diaphysis as a direct muscle attachment [21].
Ultrasound evaluation of the distal aspect of
the iliopsoas complex is improved with positioning the hip in flexion, abduction, and external rotation [22].
Rectus Femoris and Sartorius
For evaluation of the rectus femoris, assessment of both the direct (or straight) and indirect (or reflected) heads is required [24]. With
the transducer’s short axis to the rectus femoris over the AIIS, the direct head is visible
(Fig. 1C). When the transducer is moved lateral and slightly inferior while the sound beam
is being directed perpendicular to the lateral acetabular cortex to eliminate anisotropy,
the indirect head is visible. The transducer
can then be turned 90° to evaluate the separate heads in the long axis. Possible pathologic
findings includes tendinosis and a tendon tear.
This area is also a potential site for calcium hydroxyapatite crystal deposition as calcific tendinosis (Fig. 4). Ultrasound-guided lavage and
aspiration have been successfully used for percutaneous treatment [25]. Similarly, the sartorius is evaluated in the short and long axes for
muscle and tendon abnormalities.
Snapping Hip Syndrome
To evaluate for snapping iliopsoas, the
transducer is placed short axis to the psoas
major tendon of the iliopsoas complex at the
level of the ilium superior to the AIIS and is
positioned in the oblique axial plane parallel
to the inguinal ligament. The patient is then
asked to flex, abduct, and externally rotate
the hip. During this maneuver, the psoas major tendon normally rotates anterolateral relative to and around the medial iliacus muscle
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Iliopsoas Bursa
The iliopsoas bursa is a normal structure
located medial and often deep to the iliopsoas complex where the iliopsoas passes
over the ilium. Communication between the
iliopsoas bursa and the hip joint is present in
approximately 15% of individuals, although
this number increases in the presence of inflammatory arthritis and after arthroplasty
[26]. When distended, the iliopsoas bursa is
identified medial and deep to the iliopsoas
complex and may extend proximal along the
psoas musculature in the abdomen to potentially simulate a psoas abscess. In this situation, identification of hip joint communication is essential to confirm iliopsoas bursal
distention, which is most often related to a
chronic hip joint process. This communica-
tion with the hip joint is seen medial to the
psoas major tendon at the level of the femoral head with the transducer positioned transverse to the body (Fig. 1B).
Inguinal Lymph Nodes
Superficial inguinal lymph nodes are located superficial to the femoral vessels in the
femoral triangle and are bordered by the inguinal ligament, sartorius, and adductor longus [27]. The deep inguinal lymph nodes
are located deeper and medial to the femoral vessels [27]. It is common to identify
multiple inguinal lymph nodes bilaterally in
asymptomatic individuals [27].
The average short-axis measurement of
an inguinal lymph node in asymptomatic individuals is 5.4 mm (range = 2.1–13.6 mm)
with a value of 8.8 mm at 2 SDs above the
mean [27]. Because size criteria are simple
guidelines, the ultrasound characteristics
are important to determine whether a lymph
node is abnormal regardless of its size. For
example, a metastasis may cause focal asymmetric enlargement without meeting the size
criterion for enlargement.
A normal lymph node has an oval shape
with a hyperechoic hilum, uniform thickness
of the hypoechoic cortex, and a hilar pattern
of blood flow on color and power Doppler
imaging [28]. The normal hilum is echogenic because of the reflective interfaces among
fat, sinusoids, and connective tissues [28].
With hyperplastic lymph nodes, the normal
features of oval shape, echogenic hilum, uniform cortical thickness, and hilar blood flow
pattern persist, although the lymph node
may be enlarged [28]. A neoplastic lymph
node—either from metastases or primary
disease such as lymphoma—is characterized
by a round or asymmetric shape, nonuniform
cortical thickness, loss of the normal echogenic hilum, and a peripheral or mixed pattern of blood flow [28, 29].
Pubic Symphyseal Region
The pubic symphyseal region has many
anatomic structures that may be the source
of groin symptoms, especially in the athlete
[30]. One method for ultrasound evaluation
is to begin scanning the rectus abdominis
muscle in short axis inferior to the umbilicus
and then to turn the transducer 90° so that the
muscle is viewed in the long axis. The transducer is moved inferior to the pubis, where a
common aponeurosis is formed between the
insertion of each rectus abdominis and the
origin of each adductor longus tendon [30].
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Jacobson et al.
The transducer can then be moved more inferior and oblique toward the knee to maintain the long axis with the adductor musculature; external rotation of the hip assists in
this evaluation. The transducer can then be
repositioned over the symphysis pubis in the
transverse plane on the body to evaluate for
a joint abnormality. Alternatively, the pubic
symphyseal region can be examined beginning over the adductor muscles and can then
be moved proximal to visualize the common
aponeurosis and the symphysis pubis.
One of the most common abnormalities
in the symphysis pubis region in athletes involves the common aponeurosis between the
rectus abdominis and the adductor musculature [30, 31] (Fig. 5). Although the cause of
and the term “sports hernia” is often debated, abnormality of the common aponeurosis
has been described as the predominant imaging feature in patients with athletic pubalgia symptoms [31]. At the common aponeurosis, hypoechoic swelling and anechoic
clefts may be seen with cortical irregularity [32]. Less commonly, isolated tears of
the adductor compartment may be present:
A full-thickness tear is characterized by tendon retraction and interposed heterogeneous
but predominantly hypoechoic hemorrhage
in the acute and subacute setting [31]. Other proposed causes for athletic pubalgia, or
sports hernia, include a medial bulge in the
posterior wall of the inguinal canal, obturator nerve entrapment, osteitis pubis, tendon
tear, and inguinal hernias [31, 33].
Abnormalities of the pubic symphysis,
which include hypoechoic capsular distention, anechoic joint fluid, synovial hypertrophy, and cortical irregularity, may also be
detected with ultrasound [32]. The superior pubic ramus should also be evaluated for
cortical step-off or callus to indicate fracture. A cortical irregularity of the symphysis
pubis may be physiologic, related to the unfused growth plates, and may persist in patients until their mid-20s [32].
Inguinal Region Hernias
Inguinal region hernias should be considered as a primary or potentially contributing
cause for groin symptoms, which include indirect inguinal, direct inguinal, and femoral
hernias. With regard to the imaging diagnosis of hernias, one meta-analysis showed
a sensitivity of 92.7–100% and specificity
of 22.2–100% using ultrasound [34]. The
authors stressed that the imaging findings
should be correlated with physical examina-
516
tion findings to improve accuracy in the setting of an unclear clinical diagnosis [34]. Ultrasound for the diagnosis of a nonpalpable
or clinically occult hernia has proven more
difficult [35], with a sensitivity and specificity of 86% and 77%, respectively [36], and
another study showing a sensitivity of 33%
and specificity of 0% [37]. These results
likely reflect the difficulty in performing an
ultrasound examination for inguinal hernias
and further indicate the need for a clear understanding of sonographic anatomy and the
use of a comprehensive protocol.
Anatomy
There are three essential soft-tissue landmarks for orientation: the lateral margin of
the rectus abdominis, the inferior epigastric
artery, and the inguinal ligament (Fig. 6A)
[38]. These three boundaries outline Hesselbach triangle (i.e., the location of a direct inguinal hernia) (Fig. 6). Just superior to the
origin of and lateral to the inferior epigastric
artery is the location of the deep or internal
inguinal ring (i.e., the origin of an indirect
inguinal hernia) (Fig. 6). The region distal to
the inguinal ligament and medial to the femoral vasculature is the femoral canal (i.e., the
origin of a femoral hernia) (Fig. 6).
Valsalva Maneuver
An adequate Valsalva maneuver (defined
as forced expiratory effort against a closed
glottis) is essential during ultrasound examination for hernias. One method to increase
intraabdominal pressure is to have the patient “puff the cheeks out” while blowing on
the back of the hand. To ensure an adequate
Valsalva maneuver, the femoral vein distal to the inguinal ligament should distend.
Of note, some hernias are not visible during
routine Valsalva maneuvers and may require
scanning with the patient standing.
Scanning Details
To begin ultrasound evaluation for inguinal hernias, the transducer is placed short axis
to one of the rectus abdominis muscles inferior to the umbilicus [38]. As the transducer
is moved inferior, the inferior epigastric artery is identified deep to the rectus abdominis
and is followed moving laterally. Color Doppler imaging may assist in the identification
of the inferior epigastric artery, which is then
followed inferiorly to its origin at the external
iliac artery. If the transducer is moved slightly
cephalad, this area is the location of the deep
inguinal ring lateral to the inferior epigastric
artery. The transducer can then be angled parallel to the inguinal canal to assess for an indirect inguinal hernia during the Valsalva maneuver. The transducer is turned 90° over the
inguinal canal, and the Valsalva maneuver is
repeated. This latter evaluation short axis to
the inguinal canal is essential and important
to avoid diagnostic pitfalls, which we discuss
later. The transducer is then moved medial in
the transverse plane between the inferior epigastric artery and the lateral border of the rectus abdominis to evaluate for a direct inguinal hernia in Hesselbach triangle during the
Valsalva maneuver, and the transducer is also
turned 90° in the sagittal plane. Finally, the
transducer is positioned short axis to the femoral vasculature inferior to the inguinal ligament to assess for a femoral hernia during the
Valsalva maneuver. We must emphasize the
importance of documenting any hernia in two
orthogonal planes: Visualization in the sagittal plane is important to avoid diagnostic pitfalls for all inguinal region hernias.
Indirect Inguinal Hernia
The characteristic finding of an indirect
inguinal hernia is abnormal movement of intraabdominal contents (fat, bowel, or both)
through the deep inguinal ring and through
the inguinal canal [38–40] (Fig. 7 and Videos S1 and S2 [supplemental videos that can
be viewed in the AJR electronic supplement
to this article available at www.ajronline.
org]). On ultrasound, this abnormality appears as tissue of variable echogenicity moving through the deep inguinal ring, which
originates lateral to the inferior epigastric artery. This tissue then moves medial, parallel
to the skin surface within the inguinal canal
and parallel to the plane of the inguinal ligament. An extensive hernia may extend medial to and potentially through the external or
superficial inguinal ring into the scrotum or
labia majora and may present as a mass [41].
There is a significant pitfall if one relies on
imaging long axis to the inguinal canal. If the
intraabdominal contents shift inferiorly during the Valsalva maneuver, the inguinal canal
region can move inferior also and can move
out of view of the ultrasound imaging. This
is why the short-axis view of the inguinal canal (in the sagittal oblique plane) is essential
and is necessary to avoid misdiagnosis. In the
short axis, the indirect inguinal hernia can
be seen moving in and out of the plane adjacent to the spermatic cord (in males) and is
visible even if the inguinal canal shifts inferiorly (Figs. 7B and 7C and Video S2). When
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Ultrasound of the Groin
reporting an indirect inguinal hernia, one
should measure the hernia short axis in cross
section or two dimensions and also indicate
the medial extent.
Additional diagnostic pitfalls exist when
using ultrasound to evaluate for an indirect inguinal hernia. One consideration is a
spermatic cord lipoma, which may appear
similar to an indirect inguinal hernia on ultrasound [42]. Movement of the abnormal
tissue during the Valsalva maneuver cannot be used for this distinction because both
spermatic cord lipomas and indirect inguinal hernias may display minimal movement.
To distinguish between these two pathologic entities, one can evaluate the deep inguinal ring: A true indirect inguinal hernia will
show abnormal tissue extending through this
ring. Another diagnostic pitfall is round ligament varicosities seen in pregnant women,
which should not be misinterpreted as a vascular malformation [43, 44]. An uncommon
finding that can be seen in the inguinal canal
in women is a cyst of the canal of Nuck due
to a patent processus vaginalis [45].
Direct Inguinal Hernia
The characteristic finding of a direct inguinal hernia is focal intraabdominal tissue moving anteriorly through the Hesselbach triangle [38–40] (Fig. 8 and Videos
S3 and S4). On ultrasound, this tissue of
variable echogenicity will move characteristically in a posterior-to-anterior direction
and should be documented in two imaging
planes. Relying on only transverse imaging
(relative to the body) in an assessment for a
direct inguinal hernia is a significant pitfall
that may result in diagnostic inaccuracy. In
some individuals, the normal intraabdominal contents move inferior with the Valsalva maneuver (Fig. 9 and Videos S5 and S6).
Movement of this tissue under the Hesselbach triangle can simulate a direct inguinal hernia when imaged in the transverse
plane; however, if the transducer is turned
90° into the sagittal plane, this pitfall can be
avoided. In patients without a hernia, it becomes clear that there is no focal movement
of abdominal tissue but rather just broad inferior displacement. This displacement is
unlike a true direct inguinal hernia where
there is focal anterior movement of the intraabdominal contents through the Hesselbach triangle. A true direct inguinal hernia
should appear as focal movement of the intraabdominal contents through the Hesselbach triangle in two orthogonal planes. The
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size of the direct hernia, which includes the
cephalocaudad, mediolateral, and anteroposterior dimensions, should be described
during the Valsalva maneuver.
Femoral Hernia
The characteristic finding of a femoral
hernia is abnormal intraabdominal contents
moving in an inferior direction through the
femoral canal [38–40]. On ultrasound, tissue of variable echogenicity will be seen
extending inferiorly, most commonly medial to the femoral vein, potentially causing
compression of the femoral vein (Fig. 10 and
Videos S7 and S8). The abnormal inferior
movement of tissue should be seen in two orthogonal planes—both in the short axis and
in the long axis.
Reporting
Most inguinal region hernias involve abnormal movement of isoechoic or hyperechoic intraabdominal fat. Bowel showing
the characteristic circular echotexture with
possible peristalsis may also be visible. The
size of a hernia should be described in all dimensions rather than using ambiguous terms
such as “small” or “large.” It is also important to describe what is in the hernia (fat,
bowel, or both) and if the contents are reducible or irreducible. In the situation of an incarcerated hernia with ischemia, ultrasound
is often ineffective given the patient’s symptoms and CT may be indicated.
Summary
There are many potential pathologic conditions in a patient with groin symptoms. Because symptoms may be multifactorial and
history may be ambiguous or misleading, a
protocol-driven evaluation with ultrasound is
recommended. The hip joint is evaluated for
effusion, synovitis, and labral abnormalities.
The muscles and tendons, including the common aponeurosis at the pubic symphysis, are
evaluated for tendinosis and tears. Dynamic
evaluation should be considered to assess for
snapping hip syndrome. Iliopsoas bursal distention and lymph node enlargement are other considerations. Last, inguinal region hernias must be evaluated during the Valsalva
maneuver and documented in two orthogonal planes to avoid several important diagnostic pitfalls.
Acknowledgment
Illustrations courtesy of Danielle Dobbs,
Ann Arbor, MI.
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B
Fig. 1—24-year-old woman with normal anterior hip.
A, Ultrasound image with transducer in sagittal oblique plane long axis to femoral neck (N) shows femoral head (H), acetabulum (A), labrum (curved arrow), and anterior
capsule (arrowhead). Note reflected capsule (straight arrow) over femoral neck.
B, Ultrasound image with transducer in transverse plane over femoral head (H) shows iliopsoas muscle (IP) and tendon (arrow). S = sartorius.
(Fig. 1 continues on next page)
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Ultrasound of the Groin
C
Fig. 1 (continued)—24-year-old woman with normal anterior hip.
C, Ultrasound image with transducer in transverse oblique plane over ilium shows
psoas major muscle (Pm) and tendon (Pt) and rectus femoris direct head (RF). Note
lateral (Im-L) and medial (Im-M) muscle fibers of iliacus with interposed septation
(arrowhead). AIIS = anterior inferior iliac spine, V = femoral vein.
Fig. 3—17-year-old girl with labral detachment and paralabral cyst. Ultrasound
image with transducer in oblique sagittal plane long axis to femoral neck shows
labrum (asterisk) that is detached (arrow) from acetabulum (A) and associated
paralabral cyst (arrowheads). H = femoral head.
Fig. 2—19-year-old woman with pigmented
villonodular synovitis. Ultrasound image with
transducer in oblique sagittal plane long axis to
femoral neck (N) shows heterogeneous hypoechoic
synovial hypertrophy (arrows) that predominantly
distends anterior recess. Note bone erosion
(arrowheads). H = femoral head.
Fig. 4—38-year-old woman with rectus femoris calcific tendinosis. Ultrasound
image in sagittal plane shows calcium hydroxyapatite deposition (arrow) within
direct head of rectus femoris (arrowheads). Note close proximity of calcium
hydroxyapatite to femoral head (H). AIIS = anterior inferior iliac spine.
Fig. 5—40-year-old man with common aponeurosis injury. Ultrasound image with
transducer in sagittal oblique plane over pubis (P) shows hypoechoic thickening of
common aponeurosis (straight arrows) associated with cortical irregularity. Note
adductor longus tendon (arrowheads) and rectus abdominis (curved arrow).
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Fig. 6—Illustrations of inguinal region without and with
hernias. (Drawing by Dobbs D, used with permission)
A, Illustration of anterior inguinal region shows rectus
abdominis (R), inferior epigastric vessels (arrowhead),
and inguinal ligament (curved arrow), which outlines
Hesselbach triangle (H). Note deep inguinal ring
(straight arrow) at origin of inguinal canal.
B, Illustration shows direct inguinal hernia at
Hesselbach triangle (arrowhead); indirect inguinal
hernia with bowel extending through deep ring,
inguinal canal, and superficial ring (curved arrow);
and femoral hernia extending through femoral canal
(straight arrow). Note direction of specific hernias
during Valsalva maneuver, with direct inguinal hernia
moving anterior, indirect inguinal hernia moving
medial and to lesser extent inferior, and femoral
hernia moving inferior.
A
B
A
B
Fig. 7—31-year-old man with right-sided indirect inguinal hernia.
A, Ultrasound image with transducer in axial oblique plane long axis to inguinal
canal during Valsalva maneuver shows fat-containing indirect inguinal hernia
(white arrows) traversing internal ring (arrowheads) lateral to epigastric and
external iliac vessels (V) and coursing medial parallel to skin surface within
inguinal canal; left side of image is lateral. Black arrow indicates direction of
movement. See Video S1, a supplemental video; it can be viewed in AJR electronic
supplement to this article, available at www.ajronline.org.
B and C, Ultrasound image (B) and illustration (C) in sagittal oblique plane short
axis to inguinal canal during Valsalva maneuver show indirect hernia in short axis
(straight arrows) adjacent to spermatic cord (curved arrow) in inguinal canal; left
side of image is cephalad. Wavy arrow points to normal intraabdominal contents.
See Video S2. (Drawing by Dobbs D, used with permission)
C
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Ultrasound of the Groin
E
AJR:205, September 2015
A
B
C
D
Fig. 8—63-year-old man with right-sided direct inguinal hernia.
A, Ultrasound image in transverse plane over Hesselbach triangle shows direct inguinal hernia (white arrows)
extending in posterior-to-anterior direction during Valsalva maneuver, medial to inferior epigastric and external
iliac vessels (V); left side of image is lateral. Black arrow indicates direction of movement. See Video S3 in AJR
electronic supplement to this article, available at www.ajronline.org.
B and C, Axial MR images obtained during rest (B) and Valsalva maneuver (C) show direct inguinal hernia (white
arrows, C) medial to vasculature (V) extending anterior (arrowhead, C) during Valsalva maneuver with black
arrow indicating direction of hernia. Note bowel-containing left direct inguinal hernia with gas (black arrow, C).
D, Ultrasound image in sagittal plane over Hesselbach triangle shows focal direct inguinal hernia (straight
white arrows) and adjacent spermatic cord (curved arrow); left side of image is cephalad. Straight black arrow
indicates posterior-to-anterior direction of hernia in continuity with intraabdominal contents (wavy arrow). See
Video S4.
E, Sagittal MR image obtained during Valsalva maneuver shows focal anterior movement (black arrow) of
intraabdominal contents through Hesselbach triangle (straight white arrows). Note spermatic cord (curved arrow).
(Fig. 8 continues on next page)
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Jacobson et al.
F
G
Fig. 8 (continued)—63-year-old man with right-sided direct inguinal hernia.
F and G, Illustrations in sagittal plane obtained during rest (F) and Valsalva maneuver (G) show focal and anterior movement of direct inguinal hernia (straight arrows, G) in
continuity with intraabdominal contents (wavy arrow). Curved arrow = spermatic cord. (Drawings by Dobbs D, used with permission)
A
B
522
Fig. 9—42-year-old man with right-sided pseudodirect inguinal hernia.
A, Ultrasound image with transducer in transverse plane over Hesselbach triangle
during Valsalva maneuver shows normal intraabdominal contents (arrows), medial to
inferior epigastric and external iliac vessels (V); left side of image is lateral. See Video
S5 in AJR electronic supplement to this article, available at www.ajronline.org.
B and C, Ultrasound image (B) and illustration (C) in sagittal plane over
Hesselbach triangle during Valsalva maneuver show diffuse movement of normal
intraabdominal contents without focal anterior movement, bulge, or hernia (wavy
arrows); left side of image is cephalad. Curved arrow = spermatic cord. See Video
S6. (Drawing by Dobbs D, used with permission)
C
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Ultrasound of the Groin
A
B
Fig. 10—59-year-old woman with right-sided femoral hernia.
A, Ultrasound image in transverse plane inferior to inguinal ligament with transducer over femoral canal shows focal femoral hernia (arrows)
compressing femoral vein (V) during Valsalva maneuver. A = femoral artery; left side of image is lateral. See Video S7 in AJR electronic
supplement to this article, available at www.ajronline.org.
B, Ultrasound image in sagittal plane with transducer over femoral canal and medial to femoral vasculature shows focal femoral hernia
(white arrows) during Valsalva maneuver. Black arrow indicates inferior direction of movement during Valsalva maneuver; left side of image
is cephalad. See Video S8.
F O R YO U R I N F O R M AT I O N
A data supplement for this article can be viewed in the online version of the article at: www.ajronline.org.
AJR:205, September 2015
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