Radiokarpal

Radiokarpal, or radiocarpal joint, is the synovial articulation between the distal radius and the proximal row of carpal bones, primarily the scaphoid and lunate. The ulna does not directly contact the carpal bones; a fibrocartilaginous disc constituting the triangular fibrocartilage complex (TFCC) cushions the distal radioulnar joint and contributes to stability on the ulnar side of the wrist.

Structure and stability: The radiocarpal joint is enclosed by a capsule and stabilized by extrinsic ligaments, including the volar (palmar) and dorsal radiocarpal ligaments. The proximal carpal row is further stabilized relative to the radius by intercarpal ligaments, notably the scapholunate and lunotriquetral connections, which help coordinate motion within the wrist. The TFCC on the ulnar side provides additional support and load transmission.

Movements: The joint permits flexion and extension of the hand at the wrist, as well as radial (lateral) and ulnar (medial) deviation. The radiocarpal joint works in concert with the midcarpal joints to produce the full range of wrist motion.

Clinical significance: The radiocarpal joint is commonly involved in wrist injuries and degenerative conditions. Distal radius fractures, particularly those that disrupt joint congruity, can affect radiocarpal mechanics. TFCC tears, scapholunate dissociation, and other ligamentous injuries can compromise stability. Radiocarpal osteoarthritis may develop with age or after trauma. Diagnosis relies on clinical examination and imaging, including X-ray and MRI when soft tissue injury is suspected.