What is the role of the articular disc in the TMJ?

• A. It lubricates the joint capsule.
• B. It prevents forward displacement of the condyle by attaching to the articular eminence.
• C. It reduces temperature within the joint.
• D. It divides the joint into superior and inferior compartments, cushions loading, and allows smooth articulation by adapting to condyle movement.

Answer: (D)

The articular disc divides the TMJ into two functional spaces, cushions the load, and adapts to the moving condyle to keep the joint surfaces sliding smoothly. This fibrocartilaginous disc sits between the condyle and the temporal bone, forming a superior compartment (between the disc and articular eminence) and an inferior compartment (between the condyle and the disc). In the superior compartment, the condyle translates under the articular eminence, with the disc gliding in tandem to maintain smooth contact. In the inferior compartment, the condyle rotates against the disc, again with the disc adapting its shape to preserve congruence. The disc thus distributes loading across the joint, reduces wear by maintaining a consistent articular surface, and coordinates the complex movements of opening, closing, and lateral excursions.

Lubrication of the joint capsule comes from synovial fluid, not the disc itself. The disc isn’t responsible for preventing forward displacement by attaching to the articular eminence, and it does not reduce temperature within the joint.