Temporomandibular Joint Anatomy and Function

The temporomandibular joint (TMJ) is formed by the articulation of the mandibular condyle with the mandibular fossa of the temporal bone.

The articular disc of the TMJ is a thin layer of dense fibrocartilage that separates the mandibular condyle from the mandibular fossa.

The upper compartment allows for gliding movements, facilitating the opening and closing of the mouth.

The temporomandibular joint is a synovial joint, characterized by a joint cavity filled with synovial fluid.

The medial pterygoid muscle is the primary muscle responsible for elevating the mandible during chewing.

The lateral pterygoid muscle is responsible for protruding the mandible, which brings the lower jaw forward.

The posterior fibers of the temporalis muscle are responsible for retracting the mandible, pulling the lower jaw backward.

The lateral pterygoid muscle contributes to opening the mouth by pulling the mandible forward and downward.

The auriculotemporal nerve, a branch of the mandibular nerve, provides primary innervation to the TMJ.

The TMJ receives its primary blood supply from the branches of the external carotid artery.

The retromandibular vein, a branch of the external jugular vein, is the primary venous drainage of the TMJ.

The lateral ligament of the TMJ prevents posterior dislocation of the mandible, keeping the jaw from dislocating backward.

The sphenomandibular ligament extends from the sphenoid bone to the mandibular foramen, acting as a stabilizing structure for the TMJ.

Bruxism, or teeth grinding, is the most common cause of temporomandibular joint disorders (TMD).

The mandible usually dislocates anteriorly, meaning that it moves forward.

Osteoarthritis of the TMJ primarily affects the articular disc, causing wear and tear on the cartilage.

The auriculotemporal nerve, which supplies the TMJ, is often compressed in TMJ disorders, leading to referred pain to the ear.