1428 



CLINICAL AND' TOPOGRAPHICAL ANATOMY 



The Tilnar nerve and vessels, the superficial volar, and palmar cutaneous branches of the 

 median and ulnar pass over it. The ulnar artery and nerve are especially protected by 

 their position between the pisiform and hook of the hamate (unciform), and also by a 

 process of the flexor carpi ulnaris, which passes to the transverse ligament, thus forming a 

 kind of tunnel. The flexor carpi radialis passes through a separate sheath formed by the Uga- 

 ments and the groove in the greater multangular; while beneath the ligaments lie the flexor 

 tendons, the median nerve, and accompanying artery. Attached to its upper border is the 

 deep fascia of the forearm, and to its lower the palmar fascia and the palmaris longus tendon, 

 while from the lateral and medial parts arise some of the thenar and hypothenar muscles. The 

 upper border of the transverse carpal ligament corresponds to the lower of the two lines which 



Fig. 1145. — The Deeper Muscles of the Palm of the Hand. 



Flexor digitorum 

 sublimis 



Flexor digitorum 

 profundus 



Abductor pollicis longus 

 Flexor carpi radialis 

 Extensor pollicis brevis 



Abductor pollicis brevis 

 Opponens pollicis 



Abductor pollicis 



brevis 

 Flexor pollicis 

 brevis 



^v- Adductor pollicis 



cross the wrist just above the thenar and hypothenar eminences. The large synovial sheath, 

 for all the flexors of the fingers, reaches beneath and below the transverse ligaments as far as 

 the middle of the palm, and above the wrist for 3.7 to 5 cm. (1^ to 2 in.). 



The dorsal carpal (posterior annular) ligament is attached to the back of the 

 lateral margin of the radius above the styloid process, and medially to the back of 

 the styloid process of the ulna, the triquetrum and pisiform. Its direction is 

 oblique, being higher on the radial side. It contains six tendon-compartments, of 

 which four are on the radius. 



The most lateral contains the long abductor and short extensor of the thumb; the second 

 the two radial extensors of the carpus; the third, the extensor pollicis longus; this deep and narrow 

 groove can be identified when the hand is extended, by its prominent lateral margin; the fourth 

 transmits the extensor communis and extensor indicis proprius; the fifth, lying between the 



