Magnetic resonance imaging evaluation of discal attachment of superior head of lateral pterygoid muscle in individuals with symptomatic temporomandibular joint

Objective: There has been much speculation on the role of the lateral pterygoid muscle (LPM) in temporomandibular joint (TMJ) internal derangement. As a result, this muscle has been the focus of many reports attempting to understand its possible role in TMJ internal derangement. Study Design: Magnetic resonance (MR) imaging exams of 108 TMJ disorder patients were assessed for types of morphologic insertion of the superior head of LPM to the condyle-disc complex and possible correlation with disc position. The investigation was made on the sagittal T1-weighted MR images in closed- and open-mouth positions. Results: There was a lack of correlation between attachment pattern of the superior head of LPM and presence or absence of anterior disc displacement. Conclusions: The explanation of anterior disc displacement based on the attachment type of the superior head of LPM is unlikely; the type of muscular insertion does not appear to have a predictive or prognostic value for TMJ internal derangement.