Head · Skeletal muscle
Masseter (Jaw Muscle)
The masseter is the powerful muscle of the cheek that closes the jaw for chewing. Relative to its size, it is one of the strongest muscles in the body.
What it is
The masseter is a thick, rectangular muscle on each side of the face, running from the cheekbone to the lower jaw.
Where it is
The cheek, over the back of the lower jaw; you can feel it bulge when you clench your teeth.
What it does
Closes the jaw and helps grind food during chewing.
Everyday use
Chewing food and clenching the jaw use the masseter.
When things go wrong
Common problems affecting the masseter (jaw muscle)
- Jaw tension and pain from teeth grinding (bruxism)
- Temporomandibular joint (TMJ) problems
Education and reference only. This explains the anatomy in plain terms and is not a diagnosis. Sudden severe symptoms — such as crushing chest pain or collapse — are an emergency; call 999.
Looking after it
Keeping it healthy
Managing stress, avoiding excessive gum chewing, and using a dentist-provided night guard for teeth grinding can ease masseter tension.
Did you know?
An interesting fact
For its size, the masseter is one of the strongest muscles in the body and can generate a powerful bite force.
Answers
Masseter (Jaw Muscle): frequently asked questions
What does the masseter do?
The masseter is the main chewing muscle — it closes the jaw and helps grind food.
Why does my jaw ache?
Aching jaw muscles are often caused by clenching or grinding the teeth, frequently linked to stress. A dentist can check for this and may suggest a night guard.
Sources
Where this is drawn from
- NHS — Muscles and movement
- Gray's Anatomy for Students
- TeachMeAnatomy — muscular system
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