[Magnetic resonance imaging of the TMJ disc in asymptomatic volunteers].

To determine whether disc displacement of temporomandibular joint exists in asymptomatic subjects in China, we examined fifty temporomandibular joints (TMJs) of 39 asymptomatic volunteers by magnetic resonance imaging (MRI). All subjects had no history of TMJ pain, joint noise, deviation, and opening limitation, Oblique sagittal and coronal MR images were obtained by scanning perpendicular and paralell to the longitudinal axis of the condyle respectively. MR imaging depicted anterior, medial and rotational disc displacement in 32% of the asymptomatic joints. Disc displacement in asymptomatic subjects may be a predisposing factor of TMJ dysfunction.