266 



THE ARTICULATIONS 



convex surface, made uniformly even by the interosseous ligaments which bind 

 them together. 



The capsule of the ■v\Tist-joint has been usually described as four separate liga- 

 ments, and it "wall be convenient for the sake of a complete description to follow 

 this method; but it must be understood that these four portions are continuous 

 around the joint, extending from styloid process to stjdoid process on both its 

 aspects. 



The four portions are: — 



Volar radio-carpal. 

 Dorsal radio-carpal. 



Ulnar collateral. 

 Radial collateral. 



The volar (or anterior) radio-carpal (fig. 300) is a thick strong ligament, at- 

 tached superiorly to the radius immediately above the anterior margin of the 

 terminal articular facet, to the curved ridge at the root of the styloid process of 

 the radius, and to the anterior margin of the articular disc, blending with some 

 fibres of the capsule of the inferior radio-ulnar joint. It passes downward and 

 in a medial direction to be attached to both rows of carpal bones, especially the 

 second, and to the volar intercarpal ligament. 



Fig. 300. — Anterior View of Wrist. 



Ulnar radio-ulnar 

 ligament 



Ulnar collateral liga- 

 ment of wrist 

 Flexor carpi ulnaris 



Radial collateral ligament 

 of wrist 



Volar radio-carpal 



ligament 

 Tendon of flexor carpi 

 radialis 



Capsular ligament of first 

 carpo-metacarpal joint 



The strongest and most oblique fibres arise from the root of the styloid process of the radius, 

 and pass oVjliquely over the navicular, witla which only a few fibres are connected, to be inserted 

 into the lunate, capitate, and triquetral bones. Another set, less oblique, passes from the margin 

 of the facet for the lunate to be attached to the adjacent parts of the capitate, hamate, and tri- 

 quetral bones. Between the two sets of fibres, small vessels pass into the joint. 



The dorsal (or posterior) radio-carpal ligament (fig. 301) is attached above 

 to the dorsal edge of the lower end of the radius, the back of the styloid process, 

 and the posterior margin of the fibro-cartilagc. It passes downward and in a 

 infdial direction to be connected with the first row of the carpal bones, chiefly 

 with the lunate and triquetral, and the dorsal intercarpal ligament. This 

 ligament is thin and membranous. 



It is strengthened l)y (i) strong fibres passing from the back of the articular disc where 

 they are l)lcnded with t he po.sterior inferior radio-ulnar ligament, and, from the edge of the radius 

 just behind the ulnar notch, to the tTiciuotral bone; (ii) from the ridge and groove for the extensor 

 pollicis longus to the back of the lunatx; and tricpietral bones; and (iii) from the groove for the 

 rarlial extensors to the back of the navicular and lunate. It is in relation with, and strengthened 

 by, the extensor tendons which pass over it. 



The ulnar collateral ligament (fig. 301) is fan-shaped, with its apex above, at 

 the styloid process of the uliui, to which it is attached on all sides, blending with 



