15. Masseter
Origin: Zygomatic arch and maxillary process of the zygomatic bone
Insertion: Ramus of the mandible and coronoid process
Action:
- Elevation of the mandible
- Protrusion of the mandible
Innervation: Mandibular nerve – a branch of the trigeminal nerve (CN V3)


Needling
Position: Supine, often with head rotated contralaterally
Palpation: Ask the patient to clench their jaw to help isolate this muscle
Technique: Needle perpendicular along the ramus of the mandible
Caution: Low – avoid going too deep in the mid-portion of the masseter above the ramus


Video 2.16 Needling of masseter, original video by Nadine Crocker, CC BY-NC 4.0.