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Ultrasound evaluation of neuropathies around the elbow
joint: a pictorial essay
Poster No.:
P-0085
Congress:
ESSR 2016
Type:
Educational Poster
Authors:
S. Döring , C. G. Boulet , S. Malasi , M. Shahabpour , M.
1
2
3
2
2
2 1
Kichouh , M. De Maeseneer ; Sint-Agatha-Berchem/BE,
2
3
Brussels/BE, Charleroi/BE
Keywords:
Extremities, Ultrasound, Diagnostic procedure, Inflammation
DOI:
10.1594/essr2016/P-0085
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Learning objectives
The objective of this exhibit is to demonstrate normal ultrasound anatomy and pathologies
of the nerves around the elbow joint in a self-explanatory form of a pictorial essay.
Background
The nerves around the elbow joint including ulnar, radial and median nerves and their
branches are often subject to compressive neuropathies and to traumatic or neoplastic
pathologies. The ulnar nerve is most frequently involved in this location.
Ultrasound has multiple advantages over other imaging modalities such as MRI
for evaluation of nerve pathologies. It is easily available, cheaper and quickly
performed. Dynamic imaging is a particularly useful feature of ultrasound in compressive
neuropathies.
Clinical and nerve conduction tests can be often inaccurate in exact localisation of the
neural pathological site. Also, compressions of the nerves can occur at more than one
site. Ultrasound with its ability to trace nearly the entire course of the nerve can be
advantageous in such situations.
Imaging findings OR Procedure Details
We have included an overview of the anatomical course of the ulnar, median and
radial nerves in the upper extremity. These are the nerves most frequently involved
in pathologies around the elbow joint. Some typical clinical signs and symptoms of
individual nerve involvement are shortly described. Ultrasound imaging focussing on
normal appearance and pathologies of these nerves and their main branches around the
elbow has been included.
Ulnar nerve:
It arises from the medial cord of the brachial plexus (Fig 1) and runs down along the
medial side of the arm in the neurovascular compartment on the medial side of the arm
between the anterior and posterior muscular compartments (Fig 2 and 3).
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It passes through the cubital tunnel behind the medial epicondyle (Fig 4) and between
two heads of flexor carpi ulnaris muscle (Fig 5 and 6)
Patients with ulnar nerve lesions can present with typical hand deformity and sensory
symptoms such tingling, numbness and other parasthesias in the region supplied by the
ulnar nerve (Fig 7).
Anconeus epitrochlearis (accessory muscle) and instability of ulnar nerve during elbow
flexion can be present asymptomatically but can also cause ulnar neuropathy in certains
individuals (Fig 8 and 9).
Compressive ulnar neuropathy has typical ultrasound features (Fig 10).
Nerves can be severed due to penetrating wounds. Fig 11 is a case of stump neuroma
in a patient whose ulnar nerve was cut accidentally by a glass piece.
Radial nerve:
Radial nerve originates from posterior cord of brachial plexus and passes through the
triangular space and spiral groove in the posterior upper arm (Fig 1, 3 and 12). It then
moves anteriorly on the radial side at the elbow joint level and divides into deep motor
branch, posterior interosseus nerve (PIN) and superficial sensory branch (Fig 12 and 13).
Radial nerve lesions cause wrist drop and sensory symptoms in its area of sensory
supply.
The course of PIN through the supinator is depicted in ultrasound images in Figure 15,
16 and 17.
Compressive neuropathy of PIN (Fig 18, 19 and 20) causes finger drop rather than wrist
drop. It can sometimes present as resistant tennis elbow.
Median nerve:
The origin of the nerve from the lateral and medial cords (Fig 1), an overview of its course
and branches in upper extremity (Fig 21) are shown. In the upper arm it runs medially
in the neurovascular compartment; and more distally in the upper arm it moves in the
anterior muscular compartment and courses to the antecubital fossa in the elbow (Fig 3).
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In the antecubital fossa the relations of the nerve from lateral to medial are distal biceps
tendon, brachial artery and median nerve (Fig 22).
Compression of median nerve and its branch anterior interosseus nerves can cause
typical signs and symptoms (Fig 23).
Median nerve has several potential compressive sites at the elbow (Fig 24, 25 and
26). From superior to inferior, these include the supracondylar process and ligament of
Struther, lacertus fibrosus, between the two heads of pronator teres (Fig 27) and the
sublimis bridge of flexor digitorum superficialis. (Fig 28).
Kiloh-Nevin syndrome is a compressive neuropathy of the anterior interosseus nerve (Fig
29).
Benign and malignant tumors could arise from peripheral nerves. Fig 30 shows a benign
schwannoma arising from the median nerve at the elbow.
Images for this section:
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Fig. 1: Diagrammatic sketch of the brachial plexus: Ulnar nerve (encircled white)
originates from the medial cord, radial nerve (encircled blue) from the posterior cord and
median nerve (encircled green) from the lateral and medial cords of the brachial plexus.
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Fig. 2: Diagrammatic outline of the course and branches of ulnar nerve in upper
extremity (left) and hand (right): The ulnar nerve runs down medially in the neurovascular
compartment in upper arm, passes through the cubital tunnel at the elbow, moves
anteriorly and medially in the forearm down to the Guyon's canal at the wrist and then
enters the hand. It does not give any branches in the axilla and upper arm. At the elbow
and upper forearm , branches to flexor carpi ulnaris (FCU) and medial half of the flexor
digiorum profundus (FDP) muscles, sensory palmar and dorsal cutaneous branches. In
the hand, it branches off into the sensory superficial and deep motor branch supplying
the opponens, flexor and abductor digit minimi (ODM, FDM and ABDM), the dorsal and
palmar interossei, first and second lumbricals, adductor policis (ABP) and deep head of
flexor pollicis brevis (FPB).
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Fig. 3: Diagrammatic sketch of transverse section of upper arm : The ulnar nerve (orange
arrow) courses in the neurovascular compartment on the medial side of the arm together
with the median nerve (green arrow). In the distal upper arm, the ulnar nerve moves into
the posterior muscular compartment (red arrow and dashed yellow circle) and the median
nerve to the anterior muscular compartment (white arrow and dashed yellow circle). The
radial nerve in the spiral groove (blue arrow) comes in close contact with the humeral
shaft and can be injured by fractures of the shaft.
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Fig. 4: Transverse ultrasound image of the ulnar nerve in the cubital tunnel: Cubital tunnel
is an osteofibrous tunnel between medial epicondyle and olecranon process. Here, the
ulnar nerve (Un) is covered by the ligament of Osborne (arrows) which forms the roof
of the tunnel. The floor of the cubital tunnel is formed by the posterior band of the ulnar
collateral ligament (arrowheads). Photograph (upper left corner) showing positioning of
the elbow for ultrasound imaging of posterior elbow. It is also suitable for imaging the
ulnar nerve in the cubital tunnel.
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Fig. 5: Diagrammatic sketch of the ulnar nerve deep to flexor carpi ulnaris - posterior
view: Just distal to the cubital tunnel the ulnar nerve (yellow line, indicated by yellow
arrow) courses deep to an aponeurotic arch (the arcuate ligament - small black arrows)
that connects the two (ulnar and humeral) heads of flexor carpi ulnaris (green arrow).
Ulnar nerve can be compressed at this site.
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Fig. 6: Transverse ultrasound image of ulnar nerve (arrow head) between the two heads
(ulnar and humeral) heads of flexor carpi ulnaris (Fcu) connected by an aponeurotic arch
(arcuate) ligament which creates a possible compression site.
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Fig. 7: Diagrammatic sketch of ulnar claw hand: Long standing ulnar nerve lesions can
cause 'ulnar claw hand' deformity. The ulnar nerve supplies most intrinsic muscles of
the hand. Ulnar denervation leads to important atrophy of these muscles, clinically most
obvious in the first intermetacarpal space (arrow) due to atrophy of the interossei muscles.
Diagrammatic sketch demonstrating the sensory supply of the ulnar nerve (pink area) in
the dorsal (left) and palmar aspect (right) of hand. Ulnar nerve lesions can cause sensory
symptoms in this area.
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Fig. 8: Anconeus epitrochlearis muscle: The Osborne ligament forming the roof of the
cubital tunnel can occasionally be replaced by an accessory muscle, the anconeus
epitrochlearis (blue arrow). It is asymptomatic in most cases but can cause narrowing of
the cubital tunnel and compression of the ulnar nerve (yellow arrow) in the tunnel.
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Fig. 9: Unstable ulnar nerve:transverse ultrasound images of cubital tunnel with elbow in
extension (above) and in flexion (below). In the figure above, the ulnar nerve (blue arrow)
is positioned well inside the cubital tunnel between the medial epicondyle (ME) and the
olecranon. With elbow flexion, the nerve has moved completely outside the tunnel (small
white arrow) anterior to the medial epicondyle (green curved arrow shows the traject of
dislocation). The cubital tunnel is empty (blue arrow). Istability with recurrent subluxation/
dislocation and friction injury can cause ulnar neuropathy. However, it is asymptomatic
in many cases.
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Fig. 10: Ulnar neuropathy: Cubital tunnel syndrome is compression of the ulnar nerve at
the elbow. It is the second most common compressive neuropathy in the upper extremity
(after the carpal tunnel syndrome which is the commonest). On ultrasound, the general
features of neuropathy are abrupt narrowing at the site of compression, swelling of the
nerve proximal and/or distal to the compression, hyporeflective appearance with loss of
normal fascicular structure. On colour Doppler ultrasound, hyperaemia may be present.
Longitudinal ultrasound image (above) shows the change in the thickness of the nerve
clearly. The transverse ultrasound image (below) shows increased surface area (in this
case 26 mm2 (for ulnar nerve in the cubital tunnel normal surface area is </= 8 mm2) .
Note the hypoechoic appearance of the nerve with loss of fascicular structure.
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Fig. 11: Longitudinal ultrasound images: Stump neuroma after complete tear of the nerve
with glass piece: A globular swelling at the severed end of the nerve due to retraction and
random regeneration in an attempt to restore continuity of the nerve. The image below
shows two tiny (a few mm) highly hyperreflective foreign bodies (glass particles) in the
neuroma.
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Fig. 12: Diagrammatic sketch showing course and branches of the radial nerve: It moves
from the axilla to the upper arm through the triangular space and courses through the
spiral groove in mid arm and then anteriorly, medial to the lateral epicondyle. Around
elbow, it divides into the terminal superficial sensory and deep motor branch (also
known as PIN - posterior interosseus nerve). The radial nerve supplies the extensor
muscles of the upper limb. (In the figure above: 3 branches in axilla to long and medial
head of triceps and posterior cutaneous nerve of arm, 4 branches in spiral grove to
lateral and medial head of triceps and lower lateral and posterior cutaneous nerves,
branches to Brachioradialis (Brad), extensor carpi radialis longus and brevis (ECRL,
ECRB). Diagrammatic sketch depicting the course of radial nerve together with profunda
brachii artery (yellow and red lines respectively) in the triangular space. This space is
bounded by teres major (TMaj) superiorly, long head of triceps medially (Lo Tr) and
humeral shaft laterally. SS = supraspinatus, IS = infraspinatus. Diagrammatic sketch of
spiral groove (posterior view of humerus): The radial nerve (yellow line) comes in close
contact with the midshaft of humerus in the spiral groove (dotted red lines) - which is a
bare area of bone in the posterior mid-third of the humerus . It can be injured by fractures
of the humeral shaft. Note that the radial nerve moves anteriorly in the distal arm.
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Fig. 13: Gross anatomy specimen showing division of radial nerve at the elbow: The
radial nerve divides in the posterior interosseous nerve (Pin) and superficial branch (Rs). Biceps, Bi. The Pin enters the supinator (Sup) muscle underneath the fibrous proximal
edge of the superficial head, termed the arcade of Frohse (arrow).
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Fig. 14: Clinical signs and symptoms radial nerve lesions: Photograph (left) showing wrist
drop. With PIN compression the patient presents rather with finger drop. Diagrammatic
sketch (right) of posterior view of upper extremity shows sensory supply by various
branches of radial nerve - sensory symptoms may be experienced.
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Fig. 15: Arcade of Frohse and PIN (arrowhead) on transverse US image, Sup (supinator).
PIN compression can cause a muscle weakness syndrome ('finger drop' in contrast to
'wrist drop' if injury to radial nerve is more proximal). It can also cause a forearm pain
syndrome mimicking tennis elbow. Ultrasound probe position is shown in the picture on
upper left corner.
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Fig. 16: Longitudinal US image of PIN in the supinator tunnel: The PIN (arrowheads) can
be evaluated in the longitudinal plane. One should look for focal changes in thickness of
PIN, however its caliber narrows (arrow) as it enters the supinator (S), which is a normal
finding (it narrows because it gives off branches to the supinator muscle). Ultrasound
probe position is shown in the picture on upper left corner.
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Fig. 17: Transverse ultrasound image showing exit point (arrow) of Pin from the supinator
(arrowheads). It can be seen with pronation of the forearm. This is a less common
compression area of Pin. R = radius. Ultrasound probe position is shown in the picture
on upper left corner.
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Fig. 18: Transverse ultrasound image at the division of radial nerve into Pin and
superficial branch in upper forearm: the patient presented with symptoms of resistant
tennis elbow. Ultrasound examination showed normal common extensor tendons and no
signs of tennis elbow. A ganglion cyst was seen causing compression of Pin just before its
entry into the supinator. Pin compression can cause symptoms mimicking tennis elbow.
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Fig. 19: X ray and Ultrasound of elbow in a child with swelling in forearm and weakness
of finger extensors (finger drop). X ray (left) showed a soft tissue swelling with a small
calcific focus next to proximal radius. Ultrasound examination (transverse (right above),
longitudinal (right mid) and colour Doppler (right lower) revealed a highly vascular mass
completely occupying the supinator muscle and compressing the Pin. The appearance
of the mass was compatible with a cavernous angioma. The calcification on X ray had
typical appearance of a phlebolith.
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Fig. 20: Post contrast T1 weighted axial (left) and longitudinal (right) MR images of
the same patient as in Figure . The MR images are typical of a cavernous angioma in
supinator muscle. The diagnosis was confirmed by a subsequent angiography.
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Fig. 21: Diagrammatic sketch of course and branches of the median nerve: It courses
down in the neurovascular compartment of the arm on the medial side (see figure ). More
distally, it enters the anterior compartment. At the elbow, it lies medial to the biceps tendon
and brachial artery. It continues anteriorly in the forearm to the carpal tunnel at the wrist
and finally enters the hand. It does not give any branches in the axilla and arm. At the
elbow, it gives branches to pronator teres, palmaris longus, flexor digitorum superficialis
and flexor carpi radialis. Midway in the forearm, it gives off the anterior interosseus
nerve (AIN). AIN supplies the pronator quadratus, flexor pollicis longus and lateral half of
flexor digitorum profundus. In the hand the terminal recurrent thenar nerve supplies the
abductor pollicis brevis, superficial head of flexor pollicis brevis and the opponens pollicis
muscles. Median nerve also gives motor branches to 1st and second lumbricals.
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Fig. 22: Transverse ultrasound image in the antecubital fossa showing the normal
relationship of median nerve (M, curved arrow) to biceps tendon (B, arrowheads) and
brachial artery A. Median nerve is the medial most structure.
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Fig. 23: Clinical signs and symptoms: Injury to median nerve at elbow or in upper arm
results in 'hand of benediction'. (diagrammatic sketch left above). When asked to make
a fist, patient cannot flex the thumb and index finger. Injury to AIN (photo left below):
patient will not be able to give 'OK' sign. Sensory supply of median nerve (right above):
Palmar side - radial side of palm and three and a half digits (radial) shown in blue colour;
and dorsum of hand (distal tips of index, middle and half of ring finger) shown in cream
colour. Sensory symptoms may occur in these areas.
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Fig. 24: Supracondylar process and ligament of Struther: X ray (left) shows a bony
projection called the supracondylar process (arrow), which can be present as a normal
variant in upto 1% of cases. Diagrammatic sketch on right shows ligament of Struther
(green line), a fibrous band extending between the supracondylar process and medial
epicondyle. It is usually asymptomatic but could cause compression of the median nerve
(yellow line) that traverses beneath it.
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Fig. 25: Diagrammatic sketch (left) shows the median nerve (yellow line) coursing under
the lacertus fibrosus (LF) or bicipital aponeurosis (green arrow), a fibrous sheet arising
from the distal biceps tendon. This is a potential site of compression of median nerve
at the elbow. Diagrammatic sketch showing the median nerve (yellow line) coursing
between the humeral head (brown coloured, white arrow) and ulnar head (blue coloured,
green arrow) of pronator teres. The humeral head has been cut in its, central part to show
the deeper median nerve. Compression of the nerve is possible at this point.
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Fig. 26: Diagrammatic sketch of sublimis bridge: Distal to pronator teres, the median
nerve (M) runs deep to the sublimis bridge, a fibrous arch between the radial and humeral
heads of the flexor digitorum superficialis (arrows). This is also a potential compression
site of median nerve at the elbow. Compressions of the median nerve at the elbow are
comparatively rare compared to that in the carpal tunnel.
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Fig. 27: Transverse US image of median nerve (arrow) between the ulnar deep head
(arrowheads) and the larger humeral head of pronator teres. The ulnar artery (A) lies
deep to the ulnar head of the pronator teres. Compression of the median nerve between
the two heads of pronator teres causes pronator syndrome. Ultrasound probe position is
shown in the picture on upper left corner.
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Fig. 28: Transverse ultrasound image of sublimis bridge (arrowheads) covering the
median nerve (arrow). Ultrasound probe position is shown in the picture on upper left
corner.
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Fig. 29: Kiloh-Nevin syndrome: Compression of the anterior interosseous branch of the
median nerve causes Kiloh-Nevin syndrome (inability to pinch between thumb and index
i.e. inability to give 'OK' sign). The small and deeply located AIN is difficult to visualize
with ultrasound. A quicker way is to look for atrophy of the pronator quadratus (arrows)
muscle in the forearm. This is an indirect sign of AIN compression.
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Fig. 30: Schwannoma of the median nerve: Longitudinal ultrasound image (right) shows
a globular, well encapsulated, hypoechoic mass in continuity with the median nerve in the
cubital fossa. Sagittal post-contrast T1 weighted MR image shows slight enhancement on
the inferior side of the tumor. Schwannomas are benign peripheral nerve sheath tumors.
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Conclusion
Neuropathies around the elbow joint are common and ultrasound is an eficient way
of evaluating these nerves. A pictorial essay with the purpose of demonstrating the
technique and normal ultrasound anatomy as well as pathologies of the nerves around
the elbow joint can be useful in daily practice of a radiologist.
References
•
•
Ultrasound of the musculoskeletal system. Stefano Bianchi. Carlo Martinoli.
ISBN 978-3-540-42267-9 Springer Berlin Heidelberg New York.
Miller TT, Reinus WR. Nerve entrapment syndromes of the elbow, forearm,
and wrist. AJT 2010; 195: 585-584.
Personal Information
Email address of the corresponding author (S.Döring):
[email protected]
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