150 



THE ARTICULATIONS. 



Articular surfaces. These are two, and are both transversely elongated, 

 very irregular in their configuration, and divided into three portions. The 

 inferior shows : behind, three small condyles placed side by side ; in front, 

 two slightly concave facets. The superior corresponds to the first by three 

 glenoid cavities and two convex facets. 



Mode of union. For this articulation, besides the common great liga- 

 ments, there are three particular ligaments. Two of these are very short, 

 and are situated behind the carpus, underneath the great common posterior 

 ligament. They are readily perceived by removing the capsular ligament, 

 and strongly flexing the carpus. " The strongest extends vertically from 

 the internal bone of the superior row to the second and third bones of the 

 metacarpal row; the other descends obliquely from the first bone of the 

 antibrachial row to the second of the inferior row." Bigot. The third 

 ligament proper, much stronger than the other two, reaches from the 

 supercarpal to the first bone of the inferior row and the head of the external 

 metacarpal bone. It is confounded, outwardly, with the great external 

 lateral ligament; inwardly, with the common posterior ligament. Its 

 posterior border gives attachment to the fibrous arch which completes the 

 carpal sheath. This ligament has also a branch which is fixed on the 

 second bone of the upper row (Fig. 87, 4). 



Synovial membrane. This lines all the ligaments, and is prolonged 

 above and below, between the carpal bones, to facilitate 

 the gliding of their articular facets. Two upper pro- 

 longations ascend between the three first bones of the 

 antibrachial row to cover the inferior face of the inter- 

 osseous ligaments uniting them. Two other prolong- 

 ations descend between the carpal bones of the second 

 row ; the external, after covering the first interosseous 

 ligament, passes between it and the corresponding an- 

 terior ligament, and communicates with the synovial 

 capsule of the carpo-metacarpal articulation. The in- 

 ternal forms a cul-de-sac which rests on the inter- 

 osseous ligament 



CARPO-METACARPAL ARTICULATION. The carpal 

 bones of the second row articulate with the superior 

 extremity of the metacarpal bones, constituting a plani- 

 form diarthrosis. 



Articular surfaces. These are, on each side, plane 

 facets more or less inclined one on the another, and 

 continued between each other The largest is in the 



Fig. 86. 



CARPAL ARTICULA- 

 TIONS; FRONT VIEW. 

 1, 1, Anterior liga- 

 ments uniting the 



carpal bones of each middle, and is generally hollowed by a small, shallow, 



the carpo-metacar- 



ligament; 4, Com- 

 mon internal liga- 

 ment. 



Mode of union. There are the four great common 



pal articulation; 3, ligaments, and also six special ligaments: two anterior, 

 Common external i wo posterior, and two interosseous. 



Of the two anterior ligaments (Fig. 86, 2, 2), one is 

 divided into two distinct bands, and unites the second 

 bone to the principal metacarpal; the other, concealed 

 by the external lateral ligament, attaches the first bone to the head of the 

 external metacarpal bone. 



The two posterior ligaments described by Rigot do not appear to us to 



be sufficiently distinct from the great ligament to merit a special description. 



The two interosseous ligaments, completely overlooked by that able 



