Musculus masseter

The masseter muscle is one of the muscles of mastication. It is rectangular shaped and consists of three layers of fibers, where the superficial layer is the largest.

Summary

• origin: zygomatic arch
• insertion: ramus and angle of mandible
• innervation: masseteric nerve from the anterior division of the mandibular nerve
• action: elevate and protract the angle of the mandible

Gross anatomy

Superficial layer

• origin: the aponeurotic tissue arising from the maxillary process of the zygomatic bone
• insertion: muscle fibers run inferoposteriorly and insert into the angle and the posterior half of the lateral aspect of the mandibular ramus

Middle layer

• origin: the medial aspect of the anterior zygomatic arch and the lower border of the posterior zygomatic arch
• insertion: the middle part of the mandibular ramus

Deep layer

• origin: the medial aspect of the zygomatic arch
• insertion: the upper part of the mandibular ramus and the coronoid process

Relations

• Superficial: Skin, platysma, risorius, zygomaticus major, parotid duct and gland, branches of facial nerve, transverse facial branches of superficial temporal vessels
• Deep: Temporalis and ramus of mandible
• Anterior: Buccal fat pad separating masseter from buccinator and buccal nerve
• Posterior: Parotid gland

Blood supply

Blood supply is derived from several vessels:

• the masseteric branch of the maxillary artery
• the facial artery
• the transverse facial branch of the superficial temporal artery

Innervation

The masseteric nerve, a branch of the anterior division of the mandibular nerve (CN V3).

Action

The main function of masseter is to elevate the mandible and to clench the teeth. It also acts to protract the angle of the mandible.

Siehe auch:

• muscles of mastication

und weiter:

• Jochbogen
• Myositis ossificans der Kaumuskulatur