DISSECTION OF THE DOO 



133 



The strong flattened tendon 

 of the muscle is inserted 

 into the base of the fifth 

 metacarpal bone. An addi- 

 tional connection of the 

 tendon is with the annular 

 ligament of the carpus and 

 with a broad band of fascia 

 crossing the pisiform bone. 

 Between the band and the 

 bone there is a synovial 

 bursa. It should be noted 

 that, unlike the tendons of 

 the other extensors, the 

 tendon of the ulnar extensor 

 is not enclosed in a synovial 

 sheath at the carpus. 



The deep layer of muscles 

 in front of the forearm in- 

 cludes the mm. extensor 

 pollicis longus et indicis 

 proprius, abductor pollicis 

 longus and supinator. The 

 two first mentioned can be 

 completely exposed by cut- 

 ting that part of the annular 

 ligament which binds down 

 the tendons of the common 

 extensor muscle of the digits. 

 To expose the supinator 

 muscle, it is necessary to 

 reflect the radial extensor of 

 the carpus and the common 

 extensor of the digits. 



M. EXTENSOR POLLICIS 

 LONGUS ET INDICIS PROPRIUS. 



— The extensor of the first 

 and second digits is a small 

 muscle lying under cover of 

 the common extensor, with 

 an origin from the middle 

 third of the lateral border of 

 the ulna. The small tendon 



n. radialis. 

 Ramus lateralis 



n. radialis. 

 Ramus medialis 



n. uinaru. 

 Ramus dursali 



nn. digitales 



dorsales communes-^-- — - 



ii, ii I, a iv 



n. digitalis dorsalis 



. medialis et lateralis 



digiti I 



n. digitalis dorsalis 

 medialis digiti II 



Fig. 51. — Diagram of nerves on the dorsum of the manus. 



k3 



