What is the primary function of the articular disc in the temporomandibular joint?

What is the primary function of the articular disc in the temporomandibular joint?

• A. It serves as the main bony articulation for chewing.
• B. It divides the joint into upper and lower compartments and facilitates hinge-like rotation and translational movement.
• C. It provides primary nerve innervation to the joint.
• D. It permanently alters occlusion when displaced.

Answer: (B)

The key function is that the articular disc divides the temporomandibular joint into two functional compartments, upper and lower, which allows two coordinated types of movement: hinge-like rotation in the lower compartment and translational (gliding) movement in the upper compartment. This setup enables the condyle to rotate while the disc remains interposed, then slide forward under the disc during opening, producing smooth, combined jaw motion. The disc also cushions and distributes load across the joint, improving congruence and reducing wear on the bony surfaces. While some displacements can influence how the teeth come together, the disc itself isn’t a primary source of nerve supply and it isn’t the main bony articulation, nor does its normal function permanently change occlusion.

The key function is that the articular disc divides the temporomandibular joint into two functional compartments, upper and lower, which allows two coordinated types of movement: hinge-like rotation in the lower compartment and translational (gliding) movement in the upper compartment. This setup enables the condyle to rotate while the disc remains interposed, then slide forward under the disc during opening, producing smooth, combined jaw motion. The disc also cushions and distributes load across the joint, improving congruence and reducing wear on the bony surfaces. While some displacements can influence how the teeth come together, the disc itself isn’t a primary source of nerve supply and it isn’t the main bony articulation, nor does its normal function permanently change occlusion.