Oblique head position in temporomandibular joint arthrography

Thirteen patients were prospectively studied with arthrography to determine whether oblique head positions were helpful in diagnosing internal derangement of the temporomandibular joint (TMJ). After injection of contrast material, inclined transcranial lateral spot films were obtained with the patient's head in upward oblique, downward oblique, and neutral positions. The spot films were analyzed for internal derangement by assessing the size of the mass effect on the arthrogram. Twelve of the 13 arthrograms showed evidence of internal derangement of the TMJ. However, the apparent size of the mass effect varied in different head positions. Each of the three views failed to demonstrate the mass effect in at least one instance (eight different patients). No head position was better than another in demonstrating the mass effect. Thus, oblique head positions are useful adjuncts for diagnosing internal derangement of the TMJ.