PROFESSOR OWEN ON THE AYE-AYE. 63 



to the middle of the forearm : its long tendon passes under the vola-carpal ligament to 

 be inserted into the base of the index metacarpal. 



The palmaris longus {ib. fig. l,3o), with a similar but superficial origin, is a more 

 slender muscle, becomes tendinous halfway down the forearm, and is inserted partly 

 into the vola-carpal ligament, and partly expands into the volar fascia. 



The flexor carpi ulnaris (ib. fig. 1 , 29) is the largest of the superficial flexors of the 

 forearm : it arises, fleshy, from the entocondyloid ridge, and by fascia from the ulnar 

 ridge of the proximal part of the ulna ; its fibres converge to a tendon at the lower third 

 of the forearm, which is inserted into the outer part of the pisiform (p), and, by a strong 

 fascia, thence continued to the base of the fifth metacarpal. 



The flexor digitorum sublimis (PI. XXIII. figs. 1 & 3, 33) arises from the ento- 

 condyloid prominence of the humerus and from the coronoid process of the ulna, being 

 covei'ed there by the palmaris longus and flexor carpi ulnai-is ; it divides below the middle 

 of the forearm into two fasciculi, each of which again divides. The tendons of the radial 

 divisions (fig. 3, a, b) pass near each other, through the vola-carpal ligament, and 

 diverge at the palm to the index and medius digits — the latter being a very slender 

 tendon in relation to the slenderness of that finger. The ulnar pair of tendons have a 

 similar course, rather removed from the preceding, to the annulus (c) and minimus [d) 

 digits. Each tendon splits, as usual, at the base of its digit, giving passage to the 

 tendon of the deep flexor, and itself being inserted into the sides of the proximal 

 phalanx. Besides these four tendons, a short and strong one (fig. 4, e) is sent off" 

 from the inner or back part of the ulnar division of the _^e.x'or sublimis to join chiefly 

 the division of the flexor profundus which supplies the middle finger. 



The deep flexors of the digits (PL XXIII. fig. 4, 33) are two in number. The one on 

 the radial side arises by three heads, the longest (a), answering to the flexor longus 

 poinds, from the upper part of the radius ; the second (6) is a distinct strip, from the 

 radius and interosseous space ; the third (c) arises from the middle of the ulna, and 

 from the interosseous space : the two first heads unite, and afterwards join with the 

 third head, forming a strong tendon which, at the carpus, divides into two, one going 

 to the distal phalanx of the thumb, the other to that of the forefinger ; but this is 

 united at the wrist with the tendons of the ulnar division of the_^ea;or profundus. This 

 division (a) arises from the entocondyloid tubercle and the whole of the fore part of the 

 upper two-thirds of the ulna : it receives an accessory fasciculus from the middle of the 

 ulna : their common tendon unites as it passes under the carpal ligament with that of 

 the radial division by the short strip of tendon (/), then proceeds independently, and 

 divides into two strong tendons — one for the fourth, the other for the fifth finger. The 

 slender tendon of the middle finger comes off" very near the point of union of the radial 

 with the ulnar division of the flexor profundus, and also near the connecting tendon (e) 

 between the superficial and deep Qexors ; so that the action of all the flexor masses may 

 be concentrated on that slender middle finger. 



