Computed tomography followed by sectional radiography and photography as performed on eight cadaveric specimens in order to define the anatomy and normal motion of both the proximal and the distal radioulnar articulations. Osseous landmarks were defined that allowed measurement of rotation at the glenohumeral, proximal radioulnar and distal radioulnar joints as well as rotation between humerus and radius and between humerus and ulna. Findings included the absence of independent ulnar rotation and the presence of normal translatory motion at the distal radioulnar articulation that may be misinterpreted as evidence of subluxation of the distal ulna.