The articular disc has an upper portion involved in sliding and a lower portion that acts as a hinge. Which joint structure does this describe?

• A. Articular disc
• B. Capsule
• C. Condylar head
• D. Temporal fossa

Answer: (A)

In the temporomandibular joint, the articular disc sits between the temporal bone and the condyle and divides the joint into two functional spaces. The upper compartment, between the disc and the temporal bone, allows sliding (translation) as the jaw moves forward/backward. The lower compartment, between the disc and the condyle, acts as a hinge that enables rotation of the condyle. This two-part functional setup is what the description is referring to, so the structure is the articular disc. The other options don’t split into these two functional regions: the capsule is just the surrounding sleeve, the condylar head is the moving bone, and the temporal fossa is the skull space housing the joint.