330 THE ARTICULATIONS OE JOINTS. 



The proximal row of carpal articulations (Fig. 311) comprises the joints 

 between the navicular, lunate, and triquetral bones. On their adjacent aspects 

 these bones are partly articular and partly non-articular. 



Three sets of simple but strong, although short, ligamentous bands bind these 

 three carpal bones together, and form an investment for three sides of their inter- 

 carpal joints. These are (1) the ligamenta intercarpea volaria (anterior or volar liga- 

 ments), two in number, which consist of transverse fibres passing between the 

 adjacent rough volar surfaces of the bones ; (2) the ligamenta intercarpea dorsalia 

 (posterior or dorsal ligaments), also two in number, and composed of similar short 

 transverse fibres passing between the adjacent dorsal surfaces ; (3) the ligamenta 

 intercarpea interossea (interosseous ligaments) (Fig. 310), again two in number, and 

 transverse in direction, situated on a level with the proximal articular surfaces, 

 and extending from the volar to the dorsal aspect of the bones while attached to 

 non-articular areas of the opposing surfaces. The radio-carpal joint is entirely 

 shut off from the intercarpal joints, and also from the joint between the two rows 

 of carpal bones, except in rare cases, when an interosseous ligament is wanting. 



The distal row of carpal articulations (Fig. 311) includes tlie joints between 

 the greater multangular, lesser multangular, capitate, and hamate bones. Articular 

 facets occur on the opposing faces of the individual bones. 



Associated with this row there are again simple bands of considerable strength, 

 and presenting an arrangement similar to that seen in the proximal row. As in 

 the former case, they invest the intercarpal articulations, except on the proximal 

 aspect, where they communicate with the transverse carpal joint, and on the distal 

 aspect, where they communicate with the carpo-metacarpal joint cavity. 



The ligamenta intercarpea volaria (anterior or volar ligaments) are three in number. 

 They extend in a transverse direction between contiguous portions of the rough 

 volar surfaces of the bones. The ligamenta intercarpea dorsalia (posterior or dorsal 

 ligaments), also three in number, are similarly disposed on the dorsal aspect. The 

 ligamenta intercarpea interossea (interosseous ligaments) (Fig. 311) are two or three in 

 number. That which joins the capitate to the os hamatum is the strongest ; that 

 between the lesser multangular and the capitate bone is situated towards the dorsal 

 parts of their opposing surfaces ; the third, situated between contiguous non-articular 

 surfaces of the greater and lesser multangular bones, is always the feeblest, and is 

 frequently absent. 



The transverse carpal articulation (Fig. 311) is situated between the proximal 

 and distal rows of the carpus. The bones of the proximal row present the following 

 characters on their distal aspect. The lateral part of the articular surface is 

 strongly convex, both in the antero-posterior and in the transverse directions, but 

 the medial part of the same surface is concavo-convex, more especially in the trans- 

 verse direction. 



Proxirnally, the articular surfaces of the distal row of carpal bones present an 

 irregular outline. That part pertaining to the greater and lesser multangular bones 

 is concave in the antero-posterior and transverse directions, and lies at a considerably 

 more distal level than the portion belonging to the capitate and os hamatum, which 

 is, moreover, markedly convex in the antero-posterior and transverse directions, 

 with the exception of the most medial part of the os hamatum, where it is concavo- 

 convex in both of these directions. 



This articulation is invested by a complete short articular capsule (Fig. 310) 

 which binds the two rows of the carpus together, and sends prolongations to 

 the investing capsules of the proximal and distal articulations. The ligament, as a 

 whole, is very strong, and individual bands are not readily defined, although certain 

 special bands may be described. The lig. carpi radiatum (radiate carpal ligament 

 (volar ligament)) radiates from the capitate bone to the navicular, triquetral, and 

 pisiform bones. The* interval between the capitate and lunate is occupied by 

 oblique fibres, some of which pass from navicular to triquetral, while these are 

 joined by others, prolonged obliquely distally and medially, from the radial end of 

 the anterior radio-carpal ligament. By these different bands the volar aspect 

 of the joint is completely closed. 



The ligamenta intercarpea dorsalia (dorsal ligaments) are more feeble than the 



