The diagnosis of an isolated subluxation or dislocation of the distal radioulnar joint (DRUJ) may be extremely difficult to make from the standard radiographic examination. Radiographs and computerized tomographic (CT) scans of cadaver wrists were used to evaluate subluxation and dislocation of the DRUJ. Both subluxation and and dislocation could be accurately diagnosed from a true lateral radiographic projection of the wrist with the forearm in neutral rotation. Minimal supination or pronation of the forearm led to inaccurate diagnosis. A single CT scan through the DRUJ was diagnostic for subluxation and dislocation in all positions of forearm rotation. Wrist pain, plaster immobilization, or suboptimal wrist positioning may make it impossible to obtain a perfect lateral view of the wrist, thereby precluding the radiographic diagnosis of DRUJ subluxation and dislocation. In this instance, a single CT scan through the DRUJ is recommended.