328 SYNDESMOLOGY 



longus; behind, it is closely adherent to the anterior border of the articular disk 

 of the distal radioulnar articulation. 



The Dorsal Radiocarpal Ligament (ligamentum radiocarpeum dorsale; posterior 

 ligament} (Fig. 335). The dorsal radiocarpal ligament less thick and strong than 

 the volar, is attached, above, to the posterior border of the lower end of the radius; 

 its fibers are directed obliquely downward and medialward, and are fixed, below, 

 to the dorsal surfaces of the navicular, lunate, and triangular, being continuous 

 with those of the dorsal intercarpal ligaments. It is in relation, behind, with the 

 Extensor tendons of the fingers; in front, it is blended with the articular disk. 



The Ulnar Collateral Ligament (ligamentum collateral carpi ulnare; internal 

 lateral ligament) (Fig. 334). The ulnar collateral ligament is a rounded cord, 

 attached above to the end of the styloid process of the ulna, and dividing below 

 into two fasciculi, one of which is attached to the medial side of the triangular 

 bone, the other to the pisiform and transverse carpal ligament. 



The Radial Collateral Ligament (ligamentum collaterale carpi radiale; external 

 lateral ligament} (Fig. 335). The radial collateral ligament extends from the tip 

 of the styloid process of the radius to the radial side of the navicular, some of its 

 fibers being prolonged to the greater multangular bone and the transverse carpal 

 ligament. It is in relation with the radial artery, which separates the ligament 

 from the tendons of the Abductor pollicis longus and Extensor pollicis brevis. 



Synovial Membrane (Fig. 330). The synovial membrane lines the deep surfaces of the liga- 

 ments above described, extending from the margin of the lower end of the radius and articular 

 disk above to the margins of the articular surfaces of the carpal bones below. It is loose and 

 lax, and presents numerous folds, especially behind. 



The wrist-joint is covered in front by the Flexor, and behind by the Extensor tendons. 



The arteries supplying the joint are the volar and dorsal carpal branches of the radial and 

 ulnar, the volar and dorsal metacarpals, and some ascending branches from the deep volar arch. 



The nerves are derived from the ulnar and dorsal interosseous. 



Movements. The movements permitted in this joint are flexion, extension, abduction, adduc- 

 tion, and circumduction. They will be studied with those of the carpus, with which they are 

 combined. 



VII. Intercarpal Articulations (Articulationes Intercarpeae ; Articulations 



of the Carpus). 



These articulations may be subdivided into three sets: 



1 . The Articulations of the Proximal Row of Carpal Bones. 



2. The Articulations of the Distal Row of Carpal Bones. 



3. The Articulations of the Two Rows with each Other. 



Articulations of the Proximal Row of Carpal Bones. These are arthrodial 

 joints. The navicular, lunate, and triangular are connected by dorsal, volar, and 

 interosseous ligaments. 



The Dorsal Ligaments (ligamenta intercarpea dorsalia). The dorsal ligaments, 

 two in number, are placed transversely behind the bones of the first row; they 

 connect the navicular and lunate, and the lunate and triangular. 



The Volar ligaments (ligamenta intercarpea volaria; palmar ligaments). The volar 

 ligaments, also two, connect the navicular and lunate, and the lunate and trian- 

 gular; they are less strong than the dorsal, and placed very deeply behind the 

 Flexor tendons and the volar radiocarpal ligament. 



The Interosseous Ligaments (ligamenta intercarpea interossea) (Fig. 336). The 

 interosseous ligaments are two narrow bundles, one connecting the lunate with 

 the navicular, the other joining it to the triangular. They are on a level with the 

 superior surfaces of these bones, and their upper surfaces are smooth, and form 

 part of the convex articular surface of the wrist-joint. 



