Morphologic study of the mandibular fossa and the eminence of the temporomandibular joint in relation to the facial structures.

To clarify the relationship between the temporal component of the temporomandibular joint and facial bone structure, we measured anthropologic craniometric points and the structure of the mandibular fossa, including the eminence in 33 Japanese male dry skulls, with a three-dimensional apparatus. The length from the articular tubercle to the medial glenoid tubercle is correlated with skeletal variables such as the length of the fossae, the width of the masseter origin, and the mandibular length. Therefore it appears that the frontal dimension is related to the facial development, which is attributable to bite force. Goniometrically, the angle between the line deepest point of the fossa--the midpoint of the eminence and the Frankfort horizontal plane (middle angle)--was negatively correlated only with the ANB angle, suggesting that a steeper middle angle of the eminence is related to a retrusive maxilla or protrusive mandible.