Phalangeal Joints 289 



Supply. The joints about the wrist are supplied by the endings 

 of the anterior and posterior interosseous arteries and by carpal 

 branches of the radial and ulnar. The nerves come from the ulnar 

 and the posterior interosseous. 



The pisiform reflex is obtained by pressing the pisiform bone firmly 

 with the thumb on to the cuneiform bone, when, if the reflex chain be 

 entire, a motor impulse is promptly sent down to the palmaris brevis, 

 and the skin along the inner border of the hand is puckered in. 



The metacarpo-phalangeal and the inter-phalangeal joints are 

 strengthened by lateral ligaments, and in front by a thick glenoid 



Lines of incisions. (After SMITH and WALSHAM.) 



ligament containing much fibrous tissue. There is no posterior liga- 

 ment, its place being taken by the extensor tendon. Each joint has a 

 synovial membrane. 



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