The temporomandibular joint (TMJ) connects the lower jaw (mandible) to the temporal bone of the skull, just in front of each ear. The two sides always work together.
Bones and disc
The condyle of the mandible sits in a hollow of the temporal bone. A fibrocartilage disc between them splits the joint into an upper and a lower space.
Hinge and glide
Opening starts as a hinge movement, then the condyle and disc glide forward onto a bony ridge, the articular eminence. This lets the mouth open wide and the jaw move side to side.
Chewing muscles
The masseter, temporalis and medial pterygoid close the jaw, and the lateral pterygoid pulls it forward and helps open it. All are supplied by the mandibular branch of the trigeminal nerve.
Common problems
Temporomandibular disorders cause jaw pain, clicking and limited opening, often linked to clenching or grinding. If the condyle slides too far forward and locks, the jaw is dislocated and the mouth cannot close.
At the bedside
Palpate just in front of the ear while the patient opens and closes to feel for tenderness, clicking or uneven movement. The jaw thrust opens the airway by moving the mandible forward with this same gliding motion, without moving the neck.
Related guides
Written by Making Synapses. Topic reference: OpenStax, Anatomy and Physiology 2e (no text adapted).