35 2 



APPLIED ANATOMY. 



lumbrical muscles is to extend the distal and middle phalanges and to flex the prox- 

 imal ones. When, therefore, most of them are paralyzed, as occurs when the ulnar 

 nerve is divided, the distal and middle phalanges are flexed and the proximal phalan- 

 ges extended, forming the claw-hand (main griffe) of Duchenne. 



JOINTS OF THE HAND. 



The carpal bones besides being connected by short ligaments running from one 

 to another on their dorsal and palmar surface also have their adjacent surfaces con- 



Scaphoid 



Trapezoid 

 Trapezium 



Os magnum 

 Unciform 



FIG. 365. The carpal bones and joints. 



nected by interosseous ligaments. The three bones of the first row are joined by 

 two ligaments near their proximal surfaces which prevent any communication of the 

 radiocarpal with the midcarpal articulations. The four bones of the second row are 

 joined together by interosseous ligaments (fibrocartilages, Morris) which are not 

 complete. That between the os magnum and the unciform is attached more toward 

 the palmar surface, while that between the os magnum and trapezoid is more toward 

 the dorsal surface. The interosseous ligament between the trapezium and trapezoid 

 is usually lacking (Fig. 365). 



Synovial Membrane. From the above description it will be seen that the 

 joints of the carpus (with the exception of the pisiform) all communicate with one 

 another and with the carpometacarpal joints, and that the synovial membrane is prac- 

 tically continuous ; hence suppuration implicating the synovial membrane at any 



