Ultrastructure of the articular surface of the condyle in temporomandibular arthropathy.

The ultrastructure of the surface of normal human mandibular condyles is described and compared with specimens from condyles in cases of degenerative joint disease (arthropathy). Normal surfaces exhibited a nearly structurless layer about 2 microns thick, which seemed to correspond with the lamina splendens of other joints. The underlying structure of dense interlacing bundles of collagen is described. Surfaces of all pathologic condyles showed loss of lamina splendens, alteration of collagen size, and evidence of dissociation of both the collagen and its surrounding ground substance. Deeper levels showed aggregations of bizarre structures, which the authors term "vermiform bodies," and which appear to be collections of abnormal amounts and types of elastic tissue. Its distribution suggests a stress elastosis, which may contribute to the loss of mechanical integrity of articular surfaces in arthropathy. The surface changes may be reflected at the clinical level as impairment of the normal low-friction qualities of joint components associated with limitation of movement and joint sounds.