[Microvascular architecture of the temporomandibular joint in the adult rabbit as studied by the injection replica SEM method. 1. Rest position of jaws].

Microvascular architecture of the temporomandibular joint (TMJ) was studied three-dimensionally in the rabbit using the vascular casting/scanning electron microscope method. TMJ was found to be a well-vascularized organ with the most dense vascular distribution in the retro-discal region, but no blood vessels were observed in the articular disc. Morphologically the vascular networks in the upper and lower layers of the transitional area of the retro-discal region into the articular disc were different. The upper layer had a coarse, cap-shaped network beneath the synovial membrane of the superior articular space, whereas a fine and flat network was observed in the corresponding region of the lower layer. The capillaries overlying these networks took winding courses and formed hairpin-like loops at the discal ends of the networks in both layers, but the winding arrangement was more conspicuous in the lower layer, whereas the loop formation was more marked in the upper layer. The result indicate that in addition to the range of movement, the upper and lower layers may be functionally different in the production of synovial fluid and nutritional supply.