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.
