masseter muscle mas·se·ter muscle (mə-sē'tər)
A muscle with origin from the inferior border and medial surface of the zygomatic arch, with insertion into the lateral surface of the ramus of the mandible, with nerve supply from the masseteric nerve, and whose action closes the jaw during chewing.
The opening of the sinus is most commonly situated at the under margin of the mandible a little in front of the masseter muscle.
There is often a very much enlarged infra-orbital foramen through which passes a part of the masseter muscle.
The facial artery can be distinctly felt as it passes over the upper jaw at the front edge of the masseter muscle.
The masseteric fossa receives the insertion of the rostral or superficial division of the masseter muscle.