Palmar Carpal Ligament

The Guyon tunnel is located in a medial and superficial position relative to the carpal tunnel. It is delimited hy the dorsal aspect of the transverse carpal ligament and the superficial palmar carpal ligament on the radial side, and hy 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 he taken to identify the ulnar... 

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. 

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... 

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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