MRI investigation of TMJ disc and articular eminence morphology in patients with disc displacement

The aim of this study was to evaluate the morphology of the temporomandibular joint (TMJ) articular eminence and disc and the relationship between morphology and inclination in patients with disc displacement. TMJ magnetic resonance images (MRI) of 30 patients with disc displacement with reduction (DDWR) on one side and disc displacement without reduction (DDWOR) on the other side were analyzed. Articular eminence morphology was subdivided as box, sigmoid, flattened and deformed. Articular disc configuration was characterized as biconcave, biplanar, biconvex, hemiconvex and folded. The articular eminence inclination was measured as the angle between the Frankfurt plane and a line drawn from the glenoid fossa roof to the lowest point of the articular eminence. Regarding articular eminence shape, in both DDWR and DDWOR groups, the most frequent articular eminence shape was flattened shape. Regarding to the disc morphology, biplanar shape was the most frequently observed in both DDWR side and DDWOR side. The mean articular eminence inclination was 32.62 and 33.85 in the DDWR and DDWOR side, respectively. Disc and articular eminence morphology was found to have no relationship with TMJ internal derangement except the relationship between flattened type and internal derangement. The articular eminence inclination have no influence on disc reduction.