What is the primary composition of the TMJ articular disc?

• A. Elastic cartilage
• B. Dense regular connective tissue
• C. Fibrocartilaginous tissue
• D. Hyaline cartilage

Answer: (C)

The TMJ articular disc is fibrocartilaginous tissue, reflecting its role in a high-stress, load-bearing joint. Its matrix is rich in collagen fibers—primarily type I—with chondrocyte-like cells embedded in lacunae, giving it a cartilaginous, yet fibrous, character. This combination provides both toughness and resistance to shearing and compression, which is exactly what the jaw joint needs during biting and movement.

It isn’t elastic cartilage, which contains abundant elastic fibers for elasticity, or dense regular connective tissue, which lacks a true cartilaginous matrix and chondrocytes. It also isn’t hyaline cartilage, which is dominated by type II collagen and a glassy, smoother matrix. The specific fibrocartilaginous composition best explains the disc’s resilience and functional properties in the TMJ.