Articular Disc of Temporomandibular Joint (Right)
Discus articulationis temporomandibularis
Read moreStructure
The articular disc of the temporomandibular joint is located between the head of the mandibular condyle and the glenoid fossa of the temporal bone. It divides the joint into a superior and an inferior space, both filled with synovial fluid. It is oval and composed of avascular fibrous connective tissue.
Around the periphery of the disc is a thick margin, the annulus, with a depression in the center. This depression is on the inferior surface of the disc and accommodates the articular surface of the mandibular condyle, thus stabilizes the articular disc on the condyle. The disc is divided into three distinct sections. Anteriorly and posteriorly the disc is thickened, with a thinner avascular intermediate zone.
Around the condyle of the mandible, there is a capsular ligament that surrounds the lower joint capsule and fuses with the articular disc, holding it in place. Collateral ligaments are local thickenings of the capsular ligament, attaching to the medial and lateral poles of the condyle (Helland, 1980).
Related parts of the anatomy
Anatomical Relations
Anteriorly, the disc is attached to the upper head of the lateral pterygoid muscle. Posteriorly, the disc continues as a thick layer of loose connective tissue (the retrodiscal pad) that fuses to the posterior wall of the joint capsule.
Function
The articular disc of the temporomandibular joint acts as an articular surface, separating the cavity into superior and inferior spaces. It may also provide lubrication for the joint and it reduces friction between the articulating surfaces.
The disc also aids in the movement of the temporomandibular joint. Gliding movements of protrusion and retrusion occur between the temporal bone and the articular disc, whereas hinge movements of depression, elevation and rotation occur between the condyle of the mandible and the articular disc. To fully depress the mandible, the articular disc and head of the mandible move anteriorly onto the articular tubercle. These movements are controlled by the upper head of lateral pterygoid anteriorly and elastic tissue in the posterior section (Helland, 1980).
List of Clinical Correlates
—Articular disc displacement
References
Helland, M. M. (1980) Anatomy and function of the temporomandibular joint. J Orthop Sports Phys Ther, 1(3), 145-52.
