ARTICULATIONS. 



(posterior, or dorsal) between their dorsal surfaces; and two 

 (interosseous) between their lateral surfaces, at the level of 

 their superior surfaces, separating the radio-carpal from the 

 inter-carpal joints. Joints of distal row : The trapezium, trape- 

 zoid, os magnum, and unciform are united by similar ligaments, 

 three palmar, three dorsal, and three interosseous, though one 

 of the latter, between the trapezium and trapezoid, is often 

 absent. Pisi-cuneiform joint : This has a complete capsule 

 with two strengthening bands (pisi-unciform nd pisi-metacar- 

 pal) running from the lower and inner aspect of the pisiform to, 

 respectively, the hook of the unciform and the base of the 

 fifth metacarpal. [284] 



Transverse Carpal Joint. This is between the two rows; it 

 has a strong and complete capsule with certain special, though 

 not readily defined bands as follows : Palmar ligaments radiat- 

 ing from the os magnum to the scaphoid, cuneiform, and pisi- 

 form; oblique fibres filling the interval between the os mag- 

 num and semilunar, some passing from the scaphoid to the 

 cuneiform and others descending from the anterior radio-carpal 

 ligament. Dorsal ligaments of feebler structure, the chief be- 

 ing a band between the scaphoid and os magnum, and another 

 between the cuneiform and unciform. Lateral ligaments con- 

 tinuous with those of the radio-carpal joint, one (external) run- 

 ning between the radial surfaces of the scaphoid and trape- 

 zium, and the other (internal) between the ulnar surfaces of 

 the cuneiform and unciform. An interosseous ligament may 

 join the os magnum to the scaphoid. The synovial membrane 

 extends between the two rows and has prolongations between 

 the bones of each row; through absence of interosseous liga- 

 ments it may communicate with the adjacent joints. [285] 



Intermetacarpal Joints. These are arthrodial diarthroses 

 between the opposing surfaces of the bases of the four inner 

 metacarpals; their cavities are continuous with that of the 

 carpo-metacarpal joint. Three strong transverse ligaments 

 bind the adjacent palmar, dorsal, and interosseous areas of the 



[155] 



