THE CARPAL JOINTS 



239 



unciform, has somewhat the character of a condyloid joint, the os magnum and 

 unciform being the condyle, to fit into the cavity formed by tlie .scai)li()id, semi- 

 lunar, and cuneiform; the other portions are typically artln-ddial. The ligament.s 

 are: (1) anterior medio-carpal ; (2) posterior medio-carpal ; fo) transverse 

 dorsal. 



The anterior o;- palmar medio-carpal is a ligament of considerable strength, 

 consisting mostly of til)res wliich radiate from the magnum to the scajjhoid, semi- 

 lunar, and cuneiform; some few fibres connect the trapezoid and trapezium with 



Fig. 235. — Synovial Membranes of Wrist, Hand, and Fingers. 



Synovial sac of the inferior radio 

 ulnar joint 



Synovial sac of the carpus 



Synovial sac, occasionally separate, 

 for the fourth and fifth metacar- 

 pal bones 



Synovial aac of the wrist-joint 



Synovial sac of the carpo- 

 metacarpal joint of the 

 thumb 



Lateral ligaments of the metacarpo- 

 phalangeal, and inter-phalaugeal 

 joints 



the sca})hoid, an<l others pass between the unciform and cuneiform. It is covered 

 over juid thickened ])y fibrous tissue derived from the sheaths of the flexor tendons 

 and the fibres of origin of the small muscles of the thuml) and little finger. 



The posterior or dorsal medio-carpal ligament consists of fibres passing 

 obliquely from the bones of the first row to those of the second. It is stronger on 

 the ulnar side than on the radial, but is not so strong as the palmar ligament. 



The transverse dorsal ligament (fig. 234) is an additional band, well marked 

 an<l often of considerable strength, which passes across the head of the magnum 



