Muscle · Jaw

Masseter

Musculus masseter

The thick, powerful slab you can feel bulge at the back of the cheek when you bite down — it runs from the cheekbone to the angle of the jaw and is the strongest of the jaw closers for its size. Because it is superficial, easy to reach and worked constantly by unconscious clenching, it is the single most useful muscle to know for jaw tension: people who clench through stress develop a hard, tender, sometimes visibly enlarged masseter, and jaw pain, headaches and neck tightness commonly travel together in that picture.