wrists

The wrist is the complex joint that connects the forearm to the hand. It includes the radiocarpal joint between the distal radius and the first row of carpal bones, the distal radioulnar joint, and multiple intercarpal joints. The wrist is stabilized by ligaments and the triangular fibrocartilage complex (TFCC), and it supports a wide range of movements while bearing and transmitting loads to the hand.

Anatomy. Eight carpal bones form two rows: proximal (scaphoid, lunate, triquetrum, pisiform) and distal (trapezium, trapezoid, capitate, hamate). The radius and ulna form the forearm end, with the TFCC reinforcing the ulnar side and distal radioulnar joint. The radiocarpal joint primarily involves the distal radius articulating with the scaphoid and lunate, while the midcarpal joints lie between the two carpal rows and contribute to wrist motion.

Joints and movement. The radiocarpal and midcarpal joints enable flexion, extension, radial deviation (thumb side), and ulnar deviation (little finger side), with circumduction as the combined motion. The wrist works in concert with the forearm muscles to position the hand for grip and manipulation.

Ligaments, tendons, and nerves. The wrist is stabilized by volar (palmar) and dorsal radiocarpal ligaments, and radial and ulnar collateral ligaments, plus intercarpal ligaments. Extrinsic flexor and extensor tendons traverse the wrist; the carpal tunnel houses several flexor tendons and the median nerve. Blood supply comes primarily from branches of the radial and ulnar arteries. Sensation to the hand is mainly via the median and ulnar nerves, with the radial nerve supplying the dorsum of the hand.

Clinical relevance. Common issues include distal radius fractures (such as Colles fractures), scaphoid fractures, carpal tunnel syndrome, De Quervain's tenosynovitis, TFCC injuries, and ganglion cysts, all of which can affect wrist function and hand use.