296 SKELETON. 



The first of these articulations, or that of the metacarpal 

 bone of the thumb, with the trapezium, is much more movea- 

 ble than any of the others, and presents some peculiarities. It 

 is entirely distinct, slightly removed from the next, and is sur- 

 rounded by a capsule which is attached by its ends to the ar- 

 ticular margins of the bones. This capsule is strengthened by 

 additional fibres, which are particularly distinct and abundant, 

 posteriorly and externally. The synovial membrane is dis- 

 played, as usual, on the internal face of the capsule, and over 

 the articular faces. 



The other four metacarpal bones are articulated as follows: 

 The second one is joined to the trapezoides, trapezium, and mag- 

 num the third unites to the magnum alone the fourth to the 

 unciform, with a small portion of the magnum and the fifth 

 to the nnciform. The ligaments are placed before and behind, 

 and may also be termed dorsal and palmar. 



The dorsal ligaments descend from the carpal to the metacar- 

 pal bonjes. The second metacarpal bone receives two ligaments, 

 one from the trapezium, and another from the trapezoides 

 the third receives one from the rnagnum the fourth receives 

 two, one from the magnum, and the other from the unciform 

 the fifth receives one from the unciform. Transverse fibres 

 pass between these dorsal ligaments to connect the bases of the 

 metacarpal bones. 



The palmar ligaments are arranged on a plan corresponding 

 with that of the dorsal ; but, from the length of their superficial 

 fibres, are not so distinct from each other. Transverse fibres 

 pass also between the metacarpal bones of the fingers at their 

 base, and form interosseous ligaments which keep them to- 

 gether. 



The articulations thus formed and held together, are covered 

 by two synovial membranes, being processes from that between 

 the two rows of carpal bones. One of these processes, sent down 

 between the trapezoides and the magnum, displays itself over 

 the inferior surface of these bones and the head of the metacar- 

 pal bone of the fore and of the middle finger. The second pro- 

 cess which is sent down between the magnum and the unciforme, 

 is reflected over the two last carpo-metacarpal articulations. 

 These processes have a septum between them, at the ulnar side 



