[The anatomy of the ulnocarpal complex]

The ulnocarpal complex (triangular fibrocartilage complex; TFCC) represents an intricate system of structures which secures motion guidance, stability and pressure transmission in the ulnocarpal compartment of the wrist joint. Anatomically, this complex consists of the ulnocarpal disc (triangular disc), palmar and dorsal radioulnar ligaments, ulnolunate, ulnotriquetral and ulnocapitate ligaments, ulnocarpal meniscus homologue, ulnar recess (prestyloid recess), ulnocarpal collateral ligament and tendon sheath of the extensor carpi ulnaris. The distal radioulnar joint and the interosseous membrane of the forearm, which lie close together, also belong functionally to the ulnocarpal complex. Together with the proximal radioulnar joint, they permit rotational movements of the hand (pronation and supination). This review highlights all components of the ulnocarpal complex systematically. Distinctive characteristics involving size, as well as variations, are listed, and their functional meaning analyzed. The accumulated knowledge serves as a basis for possible interventions both at the ulnocarpal complex and the distal radioulnar joint.