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Muscles Involved in TMJ

12/23/14

The four primary muscles involved in TMJ syndrome that I address with massage therapy are masseter, temporalis, medial pterygoid, and lateral pterygoid. Massaging these muscles, relaxing them, may take pressure off the joint itself, relieving pain.

You can palpate (feel) a couple of these when you clench your teeth. The first one is masseter. This is a strong chewing muscle that elevates the mandible, the lower jaw bone. One end of the muscle (the origin) attaches to the zygomatic arch, the bulging part of the temporal bone that gives shape to the cheek. The other end (the insertion) attaches to the angle of the ramus of the mandible, or the corner of the jaw just below the ear. Trigger points in the belly of the masseter can cause toothaches, earaches, sinus pain and jaw pain, as well as discomfort at the temporomandibular joint (TMJ).

The other muscle you can feel (above your ear) when you clench your teeth is the temporalis, a wide, flat muscle on the side of the head. It elevates and retracts the mandible and helps close the jaw. Its origin is the temporal fossa (the hollow in the side of the skull) and fascia. Its insertion is the coronoid process of the mandible, a bony projection you can feel just below the cheek when you open your mouth wide. In addition to pulling the TMJ to the side or otherwise out of alignment, trigger points in the temporalis muscle can cause toothaches, headaches on the side of the head and forehead, and sinus pain.

The other two muscles involved in TMJ dysfunction are the pterygoids. These muscles are a challenge to palpate. It’s easiest to get to them on the inside of the mouth. The medial pterygoid closes the jaw and protrudes the mandible. Its origin is the medial surface of the lateral pterygoid plate of the sphenoid bone, the palatine bone and the pterygoid fossa. Its insertion is the inner surface of the ramus of the mandible.

The lateral pterygoid has two distinct heads. It deviates the mandible to the opposite side during chewing, opens the mouth by protruding the mandible, and closes the mandible. The origin of the superior head is the lateral surface of the greater wing of the sphenoid. The origin of the inferior head is the lateral surface of the lateral pterygoid plate. The insertion is the neck of the mandibular condyle and the articular disk of the TMJ. Trigger points in the pterygoids muscles can cause pain in the cheek area and also at the TMJ, in front of the ear.