150 



nil-: ARTICULATIONS. 



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

 Tory irrrgular in their configuration, and divided into three portions. Tho 

 inferior shows: behind, throe small condyles placed side by side; in I'mnt, 

 two slightly concave facets. Tho superior corresponds to tho first by three 

 glenoid cavities and two convex facets. 



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

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

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

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

 and strongly flexing the carpus. "Tho strongest extends vertically fn>iu 

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

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

 antibrachial row to tho second of the inferior row." Bigot. Tho third 

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

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

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

 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 

 tho gliding of their articular facets. Two upper pro- 

 longations ascend between the three first bones of the 

 antibrachial row to cover tho inferior face of the inter- 

 osseous ligaments uniting them. Two other prolong- 

 ations descend between the carpal bones of tho second 

 row ; tho external, after covering tho first interosseous 

 ligament, passes between it and the corresponding an- 

 terior ligament, and communicates with the synovial 

 capsule of the carpo-metacarpal articulation. Tho in- 

 ternal forms a cul-de-sac which rests on tho 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, piano 



l, 1, Anterior liga- facets more or less inclined one on the another, and 

 ments uniting the continued between each other. The largest is in tho 

 carpal bones i of each m iadle, and is generally hollowed by a small, shallow, 



Fig. 86. 



CARPAL ARTICULA- 

 TIONS; FRONT V1KW. 



the caqw-metacar- Mode of umon. There are the four groat common 

 l>:il articulation; 3, ligaments, and also six special liyaments : two anterior, 

 Common external two posterior, and two interosseous. 



,. ^ t^o anterior ligaments (Fig. 86, 2 2), one is 

 divided into two distinct bands, and unites the second 

 bone to tho principal metacarpal ; the other, concealed 

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

 external metacarpal bone. 



Tho two posterior ligaments described by Iligot do not appear to us to 



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



Tho two interosseous ligaments, completely overlooked by that ablo 



ment 



