Journal of the Accident and Medical Practitioners Association (JAMPA) 2008; Vol. 5 (No. 2)
 Accident and Medical Practitioners Association, New Zealand
__________________________________________________________________________________________
Common Musculoskeletal Problems of the Limbs in
Accident and Medical Practices
2. The Elbow and Forearm
William Kim, MB ChB, FAMPA, Diploma in Musculoskeletal Medicine (Otago)
Counties Care A & M Clinic, Papakura, Auckland
About the author:
Dr William Kim, MB ChB, FAMPA, is Medical Director of the Counties Care A & M Clinic,
Papakura, Auckland. His main clinical interest is musculoskeletal disorders.
Correspondence: Dr William Kim, MB ChB, FAMPA, 79-85 Great South Road, Papakura,
Auckland.
E-mail: William.Kim@orcon.net.nz
Issues this article will address

Anatomy of the elbow and forearm

Diagnosis and management of common elbow and forearm injuries
2
Salient Points

Understanding the anatomy of the forearm and elbow helps in making a diagnosis.

If compression neuropathy is suspected, a nerve conduction study is a useful tool
for locating the site of compression.

Epicondylitis of the elbow has a better outcome when a multimodality approach is
used.

When dealing with fractures in the forearm, ensure other associated fractures and
dislocations of adjacent joints are looked at.
Key words: Musculoskeletal disorders • Elbow injuries • Forearm injuries • Fractures •
Epicondylitis • Radial tunnel syndrome • Ulnar nerve compression • Pronator syndrome
…………
Introduction
This is the second article of a series dealing with musculoskeletal problems of the limbs in
accident and medical practice. The first article (JAMPA, Vol. 4, No. 2) dealt with problems in
the hand and wrist. This article focuses on common forearm and elbow conditions and
important fractures at these sites. The essential anatomy is reviewed briefly first, and then
management of the following elbow and forearm conditions is discussed:

Common elbow and forearm conditions: pulled or nursemaid’s elbow; lateral
epicondylitis; radial tunnel syndrome; medial epicondylitis; ulnar nerve compression;
pronator syndrome

Fractures: Monteggia fracture; Galeazzi fracture; Elbow fractures.
Anatomy of the Elbow and Forearm
The forearm skeleton consists of two main bones, the radius and ulna. The muscle groups of
the forearm are divided into three compartments, radial, volar and dorsal, by the antebrachial
fascia, which is a continuation of the brachial fascia in the upper arm. The fascia surrounds
the muscles of the forearm and divides the forearm into compartments by providing a
septum to the radius, ulna, and interosseous membrane.
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The radial group of muscles consists of the extensor carpi radialis longus (ECRL), the
extensor carpi radialis brevis (ECRB), and the brachioradialis. The main role of extensors in
this compartment is to provide extension and abduction to the hand (see Fig. 1).
Fig. 1. Muscle groups of the dorsal forearm (illustration from The Paddle Company[1]).
The dorsal compartment is also divided into superficial and deep parts. The superficial
compartment consists of the extensor digitorum, the extensor digiti minimi, and the extensor
carpi ulnaris (ECU). These muscles provide extension to the fingers and hand. The deep
part comprises the supinator, the abductor pollicis longus (APL), the extensor pollicis brevis
(EPB), the extensor pollicis longus (EPL), and the extensor indicis. The function of the
supinator is to rotate the forearm into the supinated position. The abductor pollicis longus
extends and abducts the thumb, while the extensors of pollicis brevis, longus and indicis
provide extension to the fingers[2] (see Fig. 1).
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The volar compartment consists of the flexor and pronator muscles. This compartment is
divided further into two parts by a transverse septum. The deep part contains the flexor
digitorum profundus (FDP), the flexor pollicis longus (FPL), and the pronator quadratus.
These are the main flexors of the phalanges of the hand. The superficial part includes the
flexor digitorum superficialis (FDS), the flexor carpi ulnaris (FCU), the flexor carpi radialis
(FCR), the palmaris longus, and the pronator teres. The flexors in the superficial part, except
for the pronator teres, assist in flexing the wrist and hand. The pronator teres participates in
pronating the forearm and flexing the elbow[2] (see Fig. 2).
Fig. 2. Muscle groups of the volar forearm (illustration from The Paddle Company[1]).
Three main nerves cross the elbow to supply forearm muscles, the median, radial and ulnar
nerves. The median nerve runs under the cover of the bicipital aponeurosis and enters the
forearm at the medial aspect between two heads of the pronator teres. It runs under the
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flexor digitorum superficialis and enters the wrist in the carpal tunnel. The median nerve
supplies all the flexor muscles in the forearm except for the flexor capri ulnaris and the
medial portion of the flexor digitorum profundus. It gives off the main branch, the anterior
interosseous nerve, deep to the pronator teres and runs anterior to the interosseous
membrane, terminating at the wrist after supplying the flexor pollicis longus, the lateral half of
the flexor digitorum profundus and the pronator quadrates.
The radial nerve enters the forearm via the space between the brachioradialis and brachialis
after descending along the spiral groove of the humerus. It then divides into two branches,
the superficial and deep radial nerves, at the level of the radiocapitellar joint. The deep radial
nerve is a pure motor branch that innervates the extensor carpi radialis brevis and the
supinator before it enters the dorsal compartment to become the posterior interosseous
nerve. In 70% of the population, the deep radial nerve enters the dorsal department through
the supinator and in 30% it enters the compartment via the proximal fibrous border of the
supinator known as the arcade of Frohse.[2] This is a common place for entrapment of this
nerve. After giving off branches to the muscles in the dorsal compartment, it terminates near
the back of the wrist as a gangliform enlargement.[2] The superficial radial nerve is a pure
sensory branch which covers the dorsum of the hand, first web area, and the proximal
phalanges of the index, middle and ring fingers.[2]
The ulnar nerve comes into the forearm between the medial epicondyle and the head of the
flexor carpi ulnaris and runs to the wrist between the flexor carpi ulnaris and the flexor
digitorum profundus. It enters the hand superficial to the flexor retinaculum. The ulnar nerve
supplies the motor function to the flexor carpi ulnaris and the medial half of the flexor
digitorum profundus.
The elbow is a modified hinge joint which provides not only flexion and extension of the joint
but also pronation and supination of the forearm. The humeroulnar and humeroradial joints
allow flexion and extension, while the humeroradial joint provides a pivot point for the
proximal radioulnar joint to pronate and supinate the forearm.[3] The elbow joint has
thickened areas of the capsule which provide the role of ligaments. Valgus stability of the
elbow is mostly provided by the anterior medial collateral ligament on the medial side. Varus
stability is mostly supported by the lateral ulnar collateral ligament. The stability of the elbow
is enhanced further by the muscles which go across the joint. These are the biceps brachii,
brachioradialis and brachialis as the flexors of the joint, the triceps and anconeus as the
extensors, the supinator and biceps brachii as the supinators, and the pronator quadratus,
pronator teres and flexor carpi radialis as the pronators.[3]
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Pulled Elbow (Nursemaid’s Elbow)
This condition is commonly found among children aged between 1 and 4 years. It occurs
when opposing directional forces are applied to the child’s elbow, e.g. when a child is picked
up by an adult by holding his or her hands or wrists, or a child moves in the opposite
direction from an adult while his or her hand is being held. The child usually presents with
the affected arm hanging loose at the side and marked reluctance to move. He or she is
usually comfortable unless the affected arm is moved. X-rays of the affected elbow and arm
are not usually necessary if the history is highly suggestive of pulled elbow. However, x-rays
may be indicated if there is any doubt or suspicion about the history, or there is swelling or
deformity over the elbow on examination.[4]
Treatment of this condition can be one of most rewarding experiences for a clinician as the
recovery can be almost instant. The affected elbow is rested on the clinician’s palm with the
thumb over the radial head area and the forearm is then supinated fully with full flexion of the
elbow by holding the hand of the affected arm. There is usually a palpable click when the
radial head is relocated.[4] The child usually starts using the affected arm once he or she
realises that there is no pain with movement. However, if the dislocation time has been long,
it may take some time for the child to move it without apprehension. If there is uncertainty
about relocation and the child is in distress after the relocation attempt, it is worthwhile to
immobilise the elbow with a crepe bandage or backlslab and put the child’s arm in a broad
arm sling with a review in 24 to 48 hours.
Tennis Elbow (Lateral Epicondylitis)
Most cases of tennis elbow are not the result of playing tennis. The cause can be idiopathic,
work- or other activity-related repetitive strain, or the result of direct trauma to the area. The
presenting symptoms are usually persisting pain over the elbow at the outer aspect and
difficulty in carrying out simple daily activities such as holding a cup, brushing the teeth or
shaving.
Examination may show maximum local tenderness over the area just anterior and about a
finger’s breadth distal to the lateral epicondyle. The pain over this area worsens with resisted
dorsiflexion of the wrist and the middle finger, and with resisted supination of the forearm.
The ‘chair test’ is a simple but effective test for diagnosing tennis elbow. The patient is asked
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to lift the back of a chair with one hand in a position of forearm pronation and wrist palmar
flexion. If positive, this elicits pain over the lateral aspect of the elbow.
There are several treatment modalities for this condition but none of them is completely
effective. The injection of a corticosteroid into the painful area can provide short-term pain
relief but there is no significant improvement in long-term pain relief.[3,5] Current treatment
includes pain control with an analgesic such as a nonsteroidal anti-inflammatory drug
(NSAID) administered locally and systemically, and avoidance of repetitive stress to the
common extensor origin that has caused pain in the affected elbow. If the pain is workrelated, it is worthwhile to consider modification of the worker’s use of the affected arm, i.e.
to avoid carrying objects with the pronated forearm in extended elbow position.[3]
Radial Tunnel Syndrome
This is one of the differential diagnoses of lateral elbow pain. Radial tunnel syndrome can
easily be mistaken for lateral epicondylitis, but can also coexist with this condition. It can
occur after injury or trauma to the distal humerus. Pain tends to be vaguer and more diffuse
in the proximal part of the forearm. It is described as achy and radiating to the dorsum of the
forearm. The pain can be present at night.
Examination shows localised tenderness over the radial tunnel which is located well distal to
the lateral epicondyle. Like tennis elbow, pain can be elicited by resisted dorsiflexion of the
middle finger and resisted supination of the forearm. Tapping over the radial tunnel can elicit
the pain over the radial nerve distribution of the forearm. Injection of a local anaesthetic into
the lateral epicondylar area can be used to distinguish radial tunnel syndrome from lateral
epicondylitis. Complete resolution of the pain is possible with lateral epicondylitis, but the
presence of residual pain may indicate radial tunnel syndrome.[3]
Nerve conduction studies are useful for confirming compression of the radial nerve over the
radial tunnel or the arcade of Frohse. Surgical treatment involves decompression of the
affected site.
Golfer’s Elbow (Medial Epicondylitis)
In this condition, pain is localised to the medial aspect of the elbow. It is similar to lateral
epicondylitis but the affected site is the common flexor origin at the medial aspect of the
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elbow. Pain increases with resisted palmar flexion of the wrist. Treatment is much the same
as for tennis elbow (see above).
Ulnar Nerve Compression and Irritation
This is one of the differential diagnoses of medial elbow pain. The ulnar nerve can become
trapped in the cubital tunnel of the ulna, or can be subluxed out of place at the ulna.[3] This
results in irritation of the nerve with vague, diffuse forearm pain, a change in sensation over
the ulnar nerve dermatome, and weakness in the muscles innervated by the ulnar nerve. As
with radial tunnel syndrome, nerve conduction studies can be helpful in locating the site of
compression. Minor symptoms from this condition can be managed with conservative
treatment involving rest, avoidance of provoking activities, and use of a resting splint.[3]
Surgical decompression is possible when conservative management fails.
Pronator Syndrome
The patient with pronator syndrome complains of altered sensation or diffuse pain over the
proximal flexor aspect of the forearm and the thenar eminence of the hand.[6] The pain is
usually brought on by prolonged muscular activity. Pain or changed sensation over these
areas is related to the cutaneous distribution of the median nerve. There is usually localised
tenderness over the median nerve distal to the elbow and increasing pain with resisted
pronation of the forearm.[3] The sites of compression can be multiple and include under the
pronator teres, the flexor digitorum superficialis, and the biceps aponeurosis. The first of
these, under the pronator teres, is the most common site for compression.[6]
Monteggia Fracture
This is a fracture of the ulna with dislocation of the radial head in the elbow (see Fig. 3). The
injury can occur with a fall on the outstretched hand with forced pronation, or with any direct
high-energy impact on the forearm. The incidence of this fracture is relatively low, less than
5% of all forearm fractures, and is easily missed, but should be considered in the presence
of any fracture along the proximal shaft of the ulna.[7] Examination of the suspected forearm
fracture must include palpation the elbow area for any tenderness or swelling. X-rays for
suspected proximal ulna fractures must include elbow views. Because of the proximity of the
main nerves over the elbow (the posterior interossesous nerve of the radial nerve, and the
median and ulnar nerves), traction nerve injury can occur.[7]
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This injury is usually a neuropraxia, and it is important to record any dysfunction of these
nerves during assessment of the injury. The Monteggia fracture is an unstable fracture and
needs operative repair.
(
Fig. 3. Monteggia fracture (illustration from Ankara University[8]).
Galeazzi Fracture
This is a fracture of the radius at the junction of the middle and distal thirds, with distal
radioulnar joint (DRUJ) dislocation or subluxation (see Fig. 4). The mechanism of this injury
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seems to be a fall onto the outstretched hand with axial loading of the pronated forearm, or a
direct impact to the dorsum of the wrist.[9] There is tenderness and swelling over the affected
distal radius and the DRUJ on clinical examination. Injury to the anterior interosseous nerve
can occur. It provides motor function to the flexor pollcis longus and the lateral half of the
flexor digitorum profundus. Palsy of this nerve will affect the pinching function of the thumb
and the index finger.
X-rays of the wrist and forearm will confirm the diagnosis. The radiological features that are
suggestive of the DRUJ disruption include fracture of the ulnar styloid, widening of the
DRUJ, relative shortening of the radius relative to the ulna by more than 5 mm, and
dislocation of the radius relative to the ulna on a true lateral x-ray view which is taken with
the shoulder abducted at 90 degrees.[9]
Fig. 4. Galeazzi fracture (illustration from LearningRadiology.com[10]).
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In adults, a Galeazzi fracture requires open reduction and internal fixation for optimal
outcome. In children, closed reduction with cast immobilisation may suffice.[9]
Elbow Fractures
In adults, the most common elbow fracture is a radial head fracture, whereas in children it is
a supracondylar fracture of the humerus. Elbow fractures can be divided into three
categories: fractures involving the distal humerus, the proximal radius, and the proximal
ulna. Clinically, elbow fractures present with pain, swelling and reduced range of movement
in the joint. It is important to consider associated injuries such as Monteggia’s fracture and
Galeazzi fracture.
Pitfalls for elbow fractures lie in interpretation of the x-ray. Although fractures in the elbow
can be quite obvious, sometimes fractures in the joint may not be very clear and the only
finding may be effusion in the joint. The fat pad sign on x-ray, particularly a posterior fat pad
sign, is indicative of joint effusion.[11] Effusion in the elbow joint should suggest subtle
fracture until proven otherwise. If fracture of the elbow is suspected, further views of the
elbow can be requested. The radiocapitellar view is helpful for looking at the radial head,
coronoid process and capitellum.[11] If there are no x-ray signs of fracture or joint effusion,
but there is a painful or swollen elbow, the patient should be reviewed 10 to 14 days after the
injury. Repeat x-ray is warranted if the elbow remains painful or is limited in motion.
Clearly displaced or markedly angulated fractures in the elbow should be referred to the
orthopaedic team for treatment. For practitioners in the accident and medical setting, the
difficult fractures are those with mild angulation and/or displacement, which may or may not
require reduction.
Isolated radial head fracture can be treated conservatively if it meets ‘the rule of threes’.[11]
This rule states if the fracture involves less than one-third of the articular surface, less than
30 degrees of angulation, and less than 3 mm of displacement on x-ray, conservative
treatment should be considered.[11] Any other fractures of the radial head and neck should be
referred for orthopaedic assessment for possible surgical treatment.
In supracondylar fractures, pure posterior, medial or lateral displacement of 50% or less of
the distal part and dorsal angulation (backward tilt) of less than 15 degrees can be accepted
for plaster immobilisation without any manipulation.[12] The anterior humeral line on the
lateral x-ray view should normally intersect the middle third of the capitellum. Any deviation
12
from this should suggest fracture with angulation. The articular surface of the distal humerus
lies 45 degrees to the axis of the humerus in the normal elbow. If this angulation becomes
less than 30 degrees, then the manipulation should be attempted for correction.[12] Other
important features are axial rotation and any significant medial or lateral tilting of the distal
fragment.
Axial rotation can be detected in the lateral view of the elbow x-ray when there is
discrepancy in the width at the supracondylar fracture site with either end of the fracture site
aligned. The normal elbow has a carrying angle of 5 to 15 degrees, and any tilting of greater
than 10 degrees in addition to the carrying angle may need reduction. The carrying angle is
defined as the angle between the long axis of the extended forearm as it lies lateral to the
long axis of the arm. Baumann’s angle can be used for checking tilting from the carrying
angle. This is the angle between the line perpendicular to the longitudinal line of the
humerus and a line via the physis of the capitellum in an anterior-posterior view. It normally
ranges from 10 to 25 degrees. The comparative x-ray of the unaffected side can be useful to
establish the normal angle. It is suggested that there is 5 to 2 ratio of change between the
Baumann and the carrying angles. A 5 degree change in Baumann’s angle will result in a 2
degree change in the carrying angle.[13]
It is important to be aware of the ossification centres in the elbow and the approximate age
of their appearance when interpreting x-rays of children with suspected fractures. The
earliest ossification centre to appear is the capitellum. This is followed by the medial
epicondyle, the trochlear, and lastly the lateral epicondyle. The approximate appearance
time at these centres is 3 months, 5 years, 8 years, and 10 years, respectively.[14] The value
of this knowledge is obvious when there is no medial epicondyle visible on x-ray in a 6-yearold child with a suspected fracture. At this age it is expected to be in place, and its absence
means that the medial epicondyle has been pulled into the joint, indicating a displaced
fracture.
References
1.
The Paddle Company. Available from:
http://www.paddleball.com/paddles/Accessories/wristbuilder/faqs.htm.
2.
Boles CA, Kannam S, Cardwell AB. The forearm: anatomy of muscle compartments
and nerves. AJR Am J Roentgenol 2000;174(1):151-9.
3.
Disabella VN. Elbow and forearm overuse injuries (article last updated Feb 12, 2008).
Available from: http://www.emedicine.com/sports/TOPIC30.
13
4.
Wolfram W. Pediatrics, Nursemaid Elbow (article last updated Jun 3, 2008). Available
from: http://www.emedicine.com/emerg/topic392.htm
5.
Boyer MI, Hastings H 2nd. Lateral tennis elbow: "Is there any science out there?". J
Shoulder Elbow Surg 1999;8(5):481-91.
6.
Werner CO, Rosen I, Thorngren KG. Clinical and neurophysiologic characteristics of
the pronator syndrome. Clin Orthop Relat Res 1985 Jul-Aug;(197):231-6.
7.
Putigna F, Strohmeyer K. Monteggia Fracture (article last updated May 24, 2007).
Available from: http://www.emedicine.com/orthoped/topic201.htm.
8.
Ankara University. Available from:
http://www.medicine.ankara.edu.tr/surgical_medical/orthopaedics/turkish/dersler/ortope
dikradyoloji/travma_files/monteggia1.jpg.
9.
Ertl JP. Galeazzi fracture (article last updated Dec 4, 2007). Available from:
http://www.emedicine.com/orthoped/topic111.htm.
10.
LearningRadiology.com. Available from:
http://www.learningradiology.com/caseofweek/caseoftheweekpix2/cow157lg.jpg.
11.
Riego de Dios R. Elbow, fractures and dislocations - adult (article last updated July 19,
2004). Available from: http://www.emedicine.com/Radio/topic234.htm.
12.
McRae R, Esser M. Practical fracture treatment, 4th ed. Edinburgh: Churchill
Livingstone, 2002.
13.
Champ LB Jr, Plancher KD. Operative treatment of elbow injuries. Berlin: Springer,
2001; p. 224.
14.
Shore RM, Grayhack JJ. Elbow trauma, pediatric (article last updated Sep 10, 2008).
Available from: http://www.emedicine.com/radio/TOPIC868.htm.