Wrist Joint Anatomy
Mobility of the hand on the forearm is provided by a series of synovial joints. Most of the movement occurs at the radiocarpal (wrist) joint, supplemented by movement between the carpal bones themselves. However, minimal rotation occurs here but is achieved for the hand by pronation and supination.
At the radiocarpal joint, the distal end of the radius and the attached articular disc articulate with the proximal row of carpal bones including, from lateral to medial, the scaphoid, lunate and triquetral (Fig. 3.94). Pisiform does not take part in the wrist joint. The articular disc attaches to the radius and the root of the ulnar styloid process and separates the cavity of the radiocarpal joint from that of the inferior radioulnar joint (Fig. 3.95). The capsule, lined by synovial membrane, attaches to the edges of the articular surfaces and is strengthened by collateral ligaments that pass from the styloid processes of the ulna and radius to the adjacent carpal bones. The movements of this joint are considered on p. 123. Function at the wrist may be severely compromised by fracture of the scaphoid across its narrow ‘waist’. This injury may deprive part of the bone of its blood supply, resulting in ischaemic necrosis.