Functional anatomy of the triangular fibrocartilage complex.

The functional anatomy of the triangular fibrocartilage complex (TFCC) was investigated in 20 fresh cadavers. Dynamic changes in the TFCC during rotation were also examined from both the proximal and distal aspects. In our analysis, the TFCC was separated into three components. The distal component was stable, functioning like a hammock to suspend the ulnar carpus. The proximal component was the fan-shaped triangular ligament, the true radioulnar ligament. This was found to originate from the fovea of the ulna in a vertical fashion and was easily twisted during rotation. The third component, the ulnar collateral ligament, also twisted during rotation. When analysed by coronal section, the internal portion of the TFCC was found to be loose, and probably serves as a cushion to absorb local deformities in the TFCC during rotation.