The articular disc of the temporomandibular joint (TMJ) plays a crucial role in dividing the joint into two distinct compartments. This disc is a biconcave fibrocartilaginous structure that separates the joint space into:

- Upper (superior) compartment, which primarily allows for gliding (translational) movements.
- Lower (inferior) compartment, which permits hinge (rotational) movements.

This division is essential for the complex biomechanics of the TMJ, enabling smooth and coordinated motions necessary for functions such as chewing, speaking, and yawning. The upper compartment facilitates forward and backward sliding movements of the mandibular condyle along the articular eminence, while the lower compartment allows for rotation of the condyle around a horizontal axis.

Understanding this anatomical and functional division helps in the diagnosis and management of TMJ disorders, as pathology may affect one or both compartments differently.

Key points:

- The articular disc divides the TMJ into two compartments: upper gliding and lower hinge.
- Upper compartment: allows translational (gliding) movement.
- Lower compartment: allows rotational (hinge) movement.
- This arrangement enables the complex mandibular movements necessary for normal jaw function.

Reference:
Gray's Anatomy, 41st Edition, Volume 1, Chapter 30: Temporomandibular Joint, Page 567-569.