152 THE UPPER EXTREMITY 



ARTICULATIO RADIO-CARPEA (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 by the navicular, 

 lunate, and triquetral bones, and the interosseous ligaments 

 which connect them together. The opposed surfaces are 

 retained in apposition by a capsular ligament in which at 

 least four thickened bands can be recognised, they are : 



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 discus articularis. 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 

 os capitatum. 



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 is also 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 lateral 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 



