Masseter muscle

Last revised by Yvette Mellam on 23 Sep 2023

The masseter muscle is one of the muscles of mastication. It is rectangular in shape and consists of three layers of inferoposteriorly oriented fibers that blend anteriorly.

  • superficial layer

    • origin: the aponeurotic tissue arising from the maxillary process of the zygomatic bone and the anterior two-thirds of the inferior aspect of the zygomatic arch

    • 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 two-thirds, and the lower border of the posterior third of the zygomatic arch

    • insertion: the central 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 1

Blood supply is derived from several vessels:

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

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.

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