THE ANGIOARCHITECTURE OF THE RAT MANDIBULAR JOINT BILAMINAR ZONE

In mammals, temporomandibular-joint articular disc attachments have a bilaminar pattern. The three-dimensional angioarchitecture of the bila minar zone in the adult rat was described using scanning election micr oscopy of microvascular corrosion casts (47 specimens) and light micro scopy of Indian ink-injected, cleared, thick-sectioned temporomandibul ar joints (6 specimens). The bilaminar zone had an axial core of feede r vessels composed primarily of hat venules which were organized in pl exuses. Arterioles were few and slender. In both laminae, there were u sually three branching levels until vessels approached the surface of the lamina, where a dense capillary meshwork was formed. Both laminae ended abruptly at the periphery of the avascular disc with a single, s lightly undulating marginal vessel. This marginal vessel, which faced the avascular disc, was definitely larger in diameter than the other s uperficial capillaries and was rather a postcapillary venule than a ca pillary. Functionally, this marginal venule might be important in sust aining nutrition of the avascular disc centre by allowing bidirectiona l blood flow during jaw movements.