ARTICULATIONS 161 



Movements at the Carpal Joints. The movements at the carpal joints 

 supplement those at the radio-carpal joint, and tend greatly to increase the 

 range of movement at the wrist. Between the individual bones of each row 

 the movement is of a gliding character, and very limited. At the trans- 

 verse intercarpal joint volar and dorsal movements (flexion and extension) 

 are alone allowed. 



By the multiplicity of joints in this part of the limb, strength and 

 elasticity is contributed to the wrist. 



Dissection. The interosseous muscles should now be removed from the 

 metacarpal bones. At the same time the flexor tendons and lumbrical 

 muscles may be detached from the fingers. The extensor tendons, how- 

 ever, should be left in position on the dorsal surfaces of the metacarpo- 

 phalangeal and interphalangeal joints. The ligaments which connect the 

 carpus and metacarpus, and those which pass between the bases of the 

 four medial metacarpal bones, should be cleaned and defined. 



ARTICULATIONES INTERMETACARPE^E (INTERMETACARPAL 

 JOINTS). 



The four metacarpal bones of the fingers articulate with 

 each other by their basal or proximal extremities, and are 

 united together by strong ligaments. The metacarpal bone 

 of the thumb stands aloof from its neighbours, and enjoys 

 a much greater freedom of movement. 



The ligaments which bind the four medial metacarpal bones 

 to each other are 



1. A series of volar and dorsal bands which pass trans- 

 versely and connect their basal extremities. 



2. Three stout interosseous ligaments, which occupy the 

 intervals between the basal ends of the bones. 



3. The transverse ligaments of the heads, which connect the 

 heads or distal extremities of the bones (p. 146). This liga- 

 ment has been removed in the dissection of the interosseous 

 muscles. 



The interosseous ligaments cannot be seen at present, but can be studied 

 later on by separating the bases of the metacarpal bones from each other. 



ARTICULATIONES CARPOMETACARPE^E (CARPO-METACARPAL 

 JOINTS). 



The metacarpal bone of the thumb articulates with the os 

 multangulum majus by a joint which is quite distinct from the 

 other carpo-metacarpal articulations. A capsular ligament 

 surrounds the joint, and is sufficiently lax to allow a very con- 



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