Description
The temporomandibular joint (TMJ) is the articulation between the mandibular condyle and the articular tubercle and mandibular (glenoid) fossa of the temporal bone. This joint is a bilateral synovial joint essential for actions involved in talking and chewing.
The TMJ has a fibrous capsule with reinforcement and accessory ligaments. The articular disc is located between the two articular surfaces of the mandibular condyle and the temporal bone and divides the articular space into superior and inferior compartments. These separate compartments have different functions. The superior compartment facilitates gliding movements (protraction and retraction), allowing the mandibular condyle to move between the mandibular fossa and the articular tubercle. The inferior compartment allows the hinge movements produced by elevation and depression of the mandible. The temporomandibular joint is therefore classified as a ginglymoarthrodial joint, as it combines hinge and gliding movements.
This TMJ is unusual since articular surfaces of synovial joints are normally covered by hyaline cartilage; however the TMJ is composed of fibrocartilage. Fibrocartilage is better able to withstand high forces, making it more suitable to withstand the large load placed on this joint.
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