Radial Nerve Superficial Branch

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. 

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... 

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. 

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. 

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... 

Fig. 10.14a-d. Radial nerve, a Photograph of the lateral aspect of the wrist showing the relationship of the superficial cutaneous branch of the radial nerve (white dashed line) with the extensor tendons of the first (I) and third (111) compartment, b-d Transverse 15-7 MHzUS images over the first compartment of the extensor tendons obtained at the levels (horizontal black bars) indicated in a show the radial nerve (arrow) as it crosses the abductor pollicis longus (APL) and extensor pollicis brevis tendons (EPB) to reach the dorsal aspect of the hand. At the wrist, the radial nerve is very small and can be depicted as a tiny hypoechoic image only when very high-frequency transducers are used... 

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... 

The thenar muscles are innervated by the recurrent branch of the median nerve and are basically responsible for the complex movement of the thumb. They include the superficial abductor pollicis brevis, the flexor pollicis brevis and the deep opponens pollicis muscles. The abductor pollicis brevis is a broad flat muscle located on the more lateral side of the thenar eminence. It arises from the radial side of the transverse carpal ligament and the tubercle of the trapezium and inserts into the base of the proximal phalanx. The flexor pollicis brevis is located medial to the abductor pollicis and has two muscular bellies the superficial head arises from the transverse carpal ligament and the tubercle of the trapezium, the deep head (first palmar interosseous muscle) from the trapezoid and the capitate. Both heads insert through the radial sesamoid over the metacar-... 

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