Fig 4. Lateral, ventral, and radioulnar joint views of the humerus (sea green), radius (black), and ulna (red) in a typical step cycle in Rattus norvegicus.

Long-axis rotation (LAR) of the radius about the ulna (radius pronation) is shown in cranial view from the perspective of the ulna (the ulna appears to be stationary in the radioulnar joint view relative to the humerus and radius). Note radius (black) LAR relative to the ulna (red). Percentages = portion of the step cycle. Black bar in ventral view = body midline based on sternum.