LECTURE III. 131 



into rounded heads, and the first bones of the 

 fingers have cup-shaped corresponding ca- 

 vities, so that considering the skeleton 

 merely, we might suppose the joint was one 

 of the ball and socket kind, admitting of 

 motion in all directions. We find, however, 

 that the ligaments are so arranged as to 

 limit the motions of the joints chiefly to 

 those of flection and extension, allowing in- 

 deed of slight motion from side to side, 

 and a slight horizontal turning of the fin- 

 ger on the end of the metacarpal bone, 

 which motions are greatest in the fore and 

 little fingers. The articular surface of this 

 convex end of the metacarpal bones con- 

 tinues so far backwards and forwards, that 

 we can extend the fingers a little beyond a 

 right line with the metacarpus, and we can 

 bend them to more than a right angle. 

 The metacarpal bones are so connected by 

 ligaments and muscles, as to prevent these 

 ends separating from one another, and spread- 

 ing, when we grasp convex bodies ; and the 

 end of the metacarpal bone, which supports 

 the little finger, has a powerful apparatus 

 of muscles expressly allotted to it, to keep 



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