The articular disk of the

temporomandibular joint In anatomy, the temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below; it is from these bones that it ...

is a thin, oval plate made of non-vascular fibrous connective tissue located between the

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bon ...

condyloid process The condyloid process or condylar process is the process on the human and other mammalian species' mandibles that ends in a condyle, the mandibular condyle. It is thicker than the coronoid process of the mandible and consists of two portions: the ...

and the cranium's

mandibular fossa The mandibular fossa, also known as the glenoid fossa in some dental literature, is the depression in the temporal bone that articulates with the mandible. Structure In the temporal bone, the mandibular fossa is bounded anteriorly by the art ...

. Its ''upper surface'' is concavo-convex from before backward, to accommodate itself to the form of the mandibular fossa and the

articular tubercle The articular tubercle (eminentia articularis) is a bony eminence on the temporal bone in the skull. It is a rounded eminence of the anterior root of the posterior end of the outer surface of the squama temporalis. This tubercle forms the front bo ...

. Its lower surface, in contact with the condyle, is concave. Its circumference is connected to the articular capsule, and in front to the tendon of the

lateral pterygoid muscle The lateral pterygoid muscle (or external pterygoid muscle) is a muscle of mastication. It has two heads. It lies superior to the medial pterygoid muscle. It is supplied by pterygoid branches of the maxillary artery, and the lateral pterygoid ne ...

. It is thicker at its periphery, especially behind, than at its center. The fibers of which the disc is composed have a concentric arrangement, more apparent at the circumference than at the center. It divides the joint into two cavities, each of which is furnished with a

synovial membrane The synovial membrane (also known as the synovial stratum, synovium or stratum synoviale) is a specialized connective tissue that lines the inner surface of capsules of synovial joints and tendon sheath A tendon sheath is a layer of synovial m ...

. It is attached as follows. * The anterior portion of the disc attaches inferiorly to the anterior condyle and superiorly to the

eminence Eminence may refer to: Places * Eminence, Arkansas, a place in Arkansas, U.S. * Eminence, Indiana, U.S. * Eminence, Kansas, U.S. * Eminence, Kentucky, U.S. * Eminence, Mississippi, in Covington County, Mississippi, U.S. * Eminence, Missouri, ...

by bending with the joint capsule. * Posteriorly, the disc attaches superiorly to the temporal bone and inferiorly to the posterior condyle (the posterior attachments are frequently called the bilaminar zone). * Laterally and medially, the disc attachments blend into the joint capsule near its attachment to the condylar head. The disc prevents the mandible from moving posteriorly.

See also

References

Further reading