WRIST JOINT 199 



ARTICULATIO RADIOCARPEA (WRIST JOINT). 



The radio-carpal or wrist joint is the joint between the 

 forearm and the hand. The proximal face of the joint is 

 formed by the distal articular surface of the radius and the 

 discus articularis ; and the distal surface consists of the navi- 

 cular, lunate, and triquetral bones, and the two interosseous 

 ligaments which connect them together. The opposed surfaces 

 are retained in apposition by an articular capsule in which at 

 least four thickened bands can be recognised, they are : 



1. Lig. radiocarpeum volare. 3. Lig. collaterale radiale. 



2. Lig. radiocarpeum dorsale. 4. Lig. collaterale ulnare. 



The capsule is attached proximally to the borders of the 

 distal ends of the radius and the ulna, and to the borders 

 of the articular disc. Distally it is connected with the bones 

 of the proximal row of the carpus, with the exception of the 

 pisiform, and some of its fibres can be traced to the capitate 

 bone. 



The volar radio-carpal ligament springs from the anterior 

 border of the styloid process of the radius and the adjacent 

 part of the anterior border of the distal end of the radius. 

 Distally it breaks up into flat bands which are attached to 

 the navicular, lunate, and capitate bones. In many cases a 

 volar ulnar-carpal ligament also is found. When present, it 

 extends from the anterior aspect of the base of the styloid 

 process and the adjacent anterior part of the head of the ulna 

 to the triquetral, pisiform, and capitate bones. 



The dorsal radio-carpal band springs from the posterior 

 border of the distal end of the radius, and is attached 

 distally to all the bones of the proximal row of the carpus, 

 except the pisiform. Its fibres are often separable into a 

 number of distinct bands. 



The radial collateral carpal ligament passes from the tip 

 of the styloid process of the radius to the lateral part of the 

 navicular ; and the ulnar collateral carpal ligament connects 

 the styloid process of the ulna with the triquetral bone. 



Articular Surfaces. Divide the anterior and collateral parts of the 

 capsule by a transverse incision carried across the front of the articulation. 

 The hand can now be bent backwards, so as to expose fully the articular 

 surfaces opposed to each other in this joint. 



The carpal surface is composed of the proximal articular 

 facets of the navicular and lunate bones, and a very small 



