82 THE SUPERIOR EXTREMITY 



Superficial septic infection in this region, unless freely incised 

 at an early stage, is apt to spread along the septa and cause 

 suppurative periostitis. Ultimately, necrosis of the phalanx 

 occurs although sometimes the base of the bone, with the 

 attachment of the flexor profundus tendon, is left behind. 



On the dor sum of the hand the superficial fascia is thin and 

 membranous. It contains most of the lymph vessels of the 

 fingers and an irregular venous network, which gives rise to the 

 basilic, median, and cephalic veins. 



Superficial Vessels and Nerves. The skin of the palm is 

 supplied, as far as the heads of the metacarpals, by palmar 

 cutaneous branches from the ulnar, median, and radial nerves. 

 The digital vessels (p. 86) and the digital nerves (p. 86), which 

 lie anterior to them, are situated in the superficial fascia on the 

 sides of the fingers, nearer the palmar than the dorsal surface. 



The skin on the dorsum is supplied by the terminal part of 

 the superficial (radial) branch of the radial (musculo-spiral) nerve 

 (p. 71) and by the dorsal cutaneous branch of the ulnar (p. 71). 



Lymph Vessels. All the superficial lymph vessels of the 

 fingers and palm, save those of the proximal part which run up 

 the front of the forearm, pass to the dorsum of the hand, and 

 become associated with the superficial veins. They are joined 

 by the deep lymph vessels of the palm, which reach the dorsum 

 by passing across the distal border of the transverse head of 

 the adductor pollicis. This arrangement explains the frequency 

 with which oedema or even metastatic abscesses may occur on the 

 dorsum of the hand, following septic infection of the fingers or 

 palm. 



Deep Fascia. The deep fascia of the forearm fuses below 

 with the palmar surface of the Transverse Carpal (Anterior 

 Annular) Ligament, which is a strong fibrous band, situated 

 in the proximal part of the hand. It provides a retentive 

 apparatus for the flexor tendons, and is attached to the pisiform, 

 and the hook of the hamate (unciform) on the ulnar side, and 

 to the navicular tubercle and the ridge of the greater multangular 

 bone (trapezium) on the radial side. A short band of fibres 

 passes from the pisiform to fuse with the palmar surface of the 

 ligament and, under cover of it, the ulnar nerve and artery are 

 continued into the palm. 



The deep fascia of the palm, which is termed the palmar 

 aponeurosis, consists of a strong central portion, and two weak 

 expansions which cover the muscles of the thenar and hypothenar 



