Morphology of the developing articular disc of the human temporomandibular joint.

The morphology of the developing articular disc of the temporomandibular joint in eight human fetuses, ranging in age from 13 weeks to 17.5 weeks, was studied. The shape of the articular disc at the time of initial delineation resembled the shape of the adult articular disc, suggesting a predominantly genetic determination. Elastin fibers were not demonstrated. The vascularity of the fetal articular disc was confined to the anterior and posterior thickened peripheral zones, with no evidence of capillaries in the thinner intermediate zone. Lateral pterygoid muscle fibers inserted into the medial aspects of the developing articular disc.