Cryosectional observations of functional anatomy of the temporomandibular joint.

The anatomy and function of the temporomandibular joint are complex, and our understanding about how the retrocondylar tissues change when the condyle translates anteriorly has been incomplete. We therefore examined the sectional anatomy of 24 fresh human temporomandibular joints at different gradations of jaw opening, protrusion, and laterotrusion. We found that the tissues of the posterior disk attachment expanded in volume and occupied the space behind the condyle when the mouth was opened, protruded, or laterotruded to the contralateral side. Volumetric expansion of the tissue seemed to be due mainly to distension of the venous structures in the retrodiskal area. In the lateral region of the joint, tissue from the superior aspect of the parotid gland also seemed to contribute to the filling of the space posterior to the condyle. Thus, the retrodiskal tissue appears to have a substantial capacity to expand and fill the mandibular fossa when the condyle translates anteriorly. The possibility of a dynamic vascular physiology is suggested.