Soft-tissue anatomy and relationships about the distal ulna.

The author investigates the complex anatomic relationship between the ulnar head and adjacent osseous structures (radius and carpus). Special attention is directed to the orientation and shape of the articular surfaces the constraining effects of specific membranes and ligaments (radio-ulnar and ulnocarpal), the shock-absorbing function of the triangular fibrocartilage, and the dynamic action of specific muscles (pronator quadratus and extensor carpi ulnaris) The anatomy of other nonstabilizing structures (meniscus homologue and prestyloid recess) is also discussed.