Masseter
The masseter is a powerful rectangular muscle of mastication that covers the lateral surface of the mandibular ramus. It is one of the strongest muscles in the body relative to its size and is the primary elevator of the mandible.
Origin, Insertion, Action, Innervation
OOrigin
Zygomatic arch (superficial part) and zygomatic bone (deep part)
IInsertion
Lateral surface of mandibular ramus and angle of mandible
AAction
- • Elevation of the mandible (closing the jaw)
- • Protraction of the mandible (superficial fibers)
NInnervation
Mandibular nerve (V3, trigeminal nerve)
Blood Supply
Masseteric artery (branch of maxillary artery)
Clinical Relevance
Masseter hypertrophy can occur with bruxism (teeth grinding). Botox injections to the masseter can treat bruxism, reduce jaw size for cosmetic purposes, or relieve TMJ pain. Lockjaw (trismus) involves masseter spasm.
Palpation
Easily palpated on the lateral face over the mandibular ramus. Have the patient clench their teeth to feel the muscle bulge.
Study Tips
- ✓Strongest bite force muscle (relative to size)
- ✓Trigeminal nerve (V3) innervates all muscles of mastication
- ✓Masseter + temporalis = elevation; pterygoids = complex movements
Study Masseter with AI
Point your camera at any muscle and get instant identification with complete details.
Download AnatomyIQMasseter FAQs
Common questions about the masseter
The masseter is innervated by the mandibular nerve (V3), which is the third division of the trigeminal nerve (CN V). This nerve innervates all four muscles of mastication.
The masseter is a powerful elevator of the mandible, closing the jaw during chewing. It generates strong bite force and is essential for mastication.
Bruxism is involuntary grinding or clenching of the teeth, often during sleep. It can cause masseter hypertrophy, jaw pain, tooth damage, and headaches. Treatment may include night guards or Botox injections.
Both are elevators of the mandible, but the temporalis is fan-shaped on the side of the skull and also retracts the mandible. The masseter is rectangular on the jaw and is more powerful for pure elevation.