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 condylar process of mandible below; it is from these bones that its name is derived. The joints are unique in their bilateral function, being connected via the mandible.

The main components are the joint capsule, articular disc, mandibular condyles, articular surface of the temporal bone, temporomandibular ligament, stylomandibular ligament, sphenomandibular ligament, and lateral pterygoid muscle.

The articular capsule (capsular ligament) is a thin, loose envelope, attached above to the circumference of the mandibular fossa and the articular tubercle immediately in front; below, to the neck of the condyle of the mandible. Its loose attachment to the neck of the mandible allows for free movement.

The unique feature of the temporomandibular joint is the articular disc. The disc is composed of dense fibrocartilagenous tissue that is positioned between the head of the mandibular condyle and the mandibular fossa of the temporal bone. The temporomandibular joints are one of the few synovial joints in the human body with an articular disc, another being the sternoclavicular joint. The disc divides each joint into two compartments, the lower and upper compartments. These two compartments are synovial cavities, which consist of an upper and a lower synovial cavity. The synovial membrane lining the joint capsule produces the synovial fluid that fills these cavities. The disc is biconcave in shape. The anterior portion of the disc serves as the insertion site for the superior head of the lateral pterygoid. The posterior portion attaches to the temporal bone. Both upper and lower compartments do not communicate with each other unless the disc is damaged.

The central area of the disc is avascular and lacks innervation, thus getting its nutrients from the surrounding synovial fluid. In contrast, the posterior ligament and the surrounding capsules along have both blood vessels and nerves. Few cells are present, but fibroblasts and white blood cells are among these. The central area is also thinner but of denser consistency than the peripheral region, which is thicker but has a more cushioned consistency. With age, the entire disc thins and may undergo the addition of cartilage in the central part, changes that may lead to impaired movement of the joint. The synovial membrane covers the inner surface of the articular capsule in the TMJ, except for the surface of the articular disc and condylar cartilage.

The lower joint compartment formed by the mandible and the articular disc is involved in rotational movement—this is the initial movement of the jaw when the mouth opens. The upper joint compartment formed by the articular disc and the temporal bone is involved in translational movement—this is the secondary gliding motion of the jaw as it is opened widely.

In some cases of anterior disc displacement, the pain felt during movement of the mandible is due to the condyle compressing this area against the articular surface of the temporal bone.^{[citation needed]}

There are three ligaments associated with the temporomandibular joints: one major and two minor ligaments. These ligaments are important in that they define the border movements, or in other words, the farthest extents of movements, of the mandible. Movements of the mandible made past the extents functionally allowed by the muscular attachments will result in painful stimuli, and thus, movements past these more limited borders are rarely achieved in normal function.