Bilateral internal derangements of temporomandibular joint: evaluation by magnetic resonance imaging.

Two hundred eleven patients with signs and symptoms of temporomandibular joint (TMJ) internal derangements were referred for magnetic resonance imaging. Both TMJs of each patient were routinely evaluated in this prospective investigation. With 422 joints examined, 29% (61) of the patients had bilaterally normal findings, 21% (45) of the patients had one normal side and one abnormal side, and 50% (105) of the patients showed bilateral internal derangements. This clinical study demonstrated a high likelihood of bilateral internal derangements in patients with symptoms of TMJ internal derangements.