The articular surfaces of the temporomandibular joint (TMJ) are covered by which type of cartilage?

Correct answer: D. Fibrocartilage

• A. Calcified cartilage is the transition zone between hyaline cartilage and subchondral bone in long bones — not an articular surface.
• B. Elastic cartilage is found in the external ear (pinna) and epiglottis — not in synovial joint surfaces.
• C. Hyaline cartilage covers the articular surfaces of most synovial joints (knee, hip, shoulder) but NOT the TMJ. The mandibular condyle and articular eminence are covered by fibrocartilage.
• D. CORRECT. Unlike most other synovial joints (which are covered by hyaline cartilage), the TMJ articular surfaces are covered by fibrocartilage. The articular disc is also fibrocartilage. This fibrocartilage is avascular and better adapted to withstand the compressive and tensile forces of jaw function. This is a key distinguishing anatomical fact about the TMJ.