orbicularis oris muscle (anatomy)

Last reviewed 01/2018

Orbicularis oris is one of the muscles of the mouth. It arises from structures around the mouth:

  • anterior surface of maxilla
  • anterior surface of mandible
  • modiolus at angle of mouth; at these points, orbicularis oris blends with fibres of buccinator

It inserts into the mucous membrane at the margin of the lips.

It is innervated by the buccal branch of the facial nerve (CN VII).

Orbicularis oris acts to:

  • close the mouth
  • purse the lips
  • evert the lips
  • modify the airflow during articulation