The fine vasculature of the rat mandibular joint

There is no detailed description of the fine vasculature of the rat mandibular joint in the literature. The gross vasculature of the cephalic area and of the mandible is known, but without particular emphasis on the joint itself. This article describes the fine vasculature of the rat mandibular joint, using transverse (coronal) and sagittal thick sections of specimens injected with India ink and analyzed with light microscopy. The main vascular supply to the joint comes from the rostral and caudal aspects. Medially, the joint is directly vascularized by vessels from the lateral pterygoid muscle. Rostrally, the synovial membrane and the bilaminar zone of the disc are supplied by articular branches from the rostral deep temporal vessels, terminal branches of the maxillary artery. Caudally, the rich synovium of the retrodiscal pad and the bilaminar zone are supplied by the articular branches of the caudal deep temporal artery, a branch of the maxillary artery. Venous return is into the short, but large retroarticular vein which empties into the maxillary vein together with the vein from the transverse sinus exiting from the postglenoid foramen. Intra-articular synovial membranes own rich venous plexuses, and are lined by a dense capillary network. The central part of the fibrous articular disc is avascular in adult rats, and is circumferentially lined by a rim of capillaries from the bilaminar zone.