A cadaveric study of the anatomy and stability of the distal radioulnar joint in the coronal and transverse planes.

Fifty preserved cadaver wrist specimens were studied. The anatomy of the distal radioulnar joint is complex, with varying configurations in the transverse and midcoronal planes. There is disparity in the radii of curvature of the sigmoid notch and the ulna-articular surface in the transverse plane, with resultant articular incongruity. Motion at the distal radioulnar joint is, hence, likely to be a combination of sliding and rotation with a small area of true appositional contact. The palmar osteocartilaginous lip of the sigmoid notch, along with the interosseous membrane, may be of importance in distal radioulnar stability. Palmar and dorsal radioulnar ligaments may act as "check-rein" ligaments, especially when seen with the "flat face" (type A) sigmoid notch.