Muscles

Masseter

Primary cause of jaw pain, ear pain and bruxism-related headache — the strongest muscle of mastication per gram.

Referred pain map

Masseter — (A) superficial-layer trigger points referring to the cheek, upper and lower molars and the TMJ; (B) lower superficial points referring to the lower jaw and mandible; (C) upper superficial points referring to the eyebrow, forehead and lower jaw; (D) deep-layer trigger point behind the zygomatic arch referring to deep ear pain and the side of the head — the most common muscular source of jaw pain, tooth pain and ear pain in bruxism and TMJ dysfunction.

Overview

Thick superficial muscle running from the zygomatic arch to the angle of the mandible. Elevates and protrudes the jaw. Trigger points are extremely common in bruxers and people with TMJ dysfunction.

Trigger point locations

Superficial layer points along the body of the muscle, plus deep layer points behind the zygomatic arch (often intraorally accessible).

Referred pain pattern

Superficial points refer to the upper and lower molars, eyebrow and TMJ. Deep points refer to deep ear pain and the side of the head.

Palpation & testing

Externally with pincer grip on the cheek and jaw angle. Intraorally with a gloved finger for deep fibers.

Common causes

Bruxism (day and night), clenching under stress, chewing gum, malocclusion, prolonged dental work.

Self-care & clinical treatment

Awareness of clenching, soft-diet phase during flare-ups, jaw relaxation drills, intraoral and extraoral self-massage. Clinically: needling (extra- and intraoral), occlusal splint referral when indicated.

Symptoms commonly linked

References

• Travell & Simons, Vol. 1