pages 328

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 collaterale 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. 336).—The synovial membrane lines the deep surfaces of the ligaments 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, adduction, and circumduction. They will be studied with those of the carpus, with which they are combined.

6g. Intercarpal Articulations

(Articulationes Intercarpeæ; 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 triangular; 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.

Contents -SUBJECT INDEX -BIBLIOGRAPHIC RECORD -ILLUSTRATION INDEX