Magnetic resonance imaging of the TMJ disc in asymptomatic volunteers.

Forty-two temporomandibular joints (TMJs) in 21 asymptomatic volunteers were visualized by magnetic resonance imaging (MRI). The subjects, 12 males and nine females, were between 23 and 43 years of age and had no history of TMJ pain, joint noise, limited opening, or previous treatment for TMJ disorder. A cephalometric head-holder was designed to position the TMJ in an accurate and reproducible manner and multisection parasagittal images were obtained perpendicular to the longitudinal axis of the condyle. MR images depicted anterior disc position in 32% of the asymptomatic joints (8/24 males, 5/18 females). Anterior disc position in asymptomatic subjects may be a predisposing factor to TMJ dysfunction or simply an anatomic variant whose prevalence must be considered when evaluating TMJ dysfunction.