Head and Neck Anatomy: Part II – Musculature
Orbicularis Oris

The orbicularis oris is found in the lips. It is interesting in that it incorporates the fibers of the numerous muscles that insert into it as it encircles the mouth within the upper and lower lips. This complicated collection of muscle fibers running in various directions, connected to different muscles and in different layers allows the orbicularis oris complex to contort the lips into a wide variety of shapes making the playing of everything from oboes to tubas possible. More importantly for daily life the lips act to keep food in the mouth when chewing without getting bitten and produce the proper shape to help speak the dozens of phonemes that humans use to communicate.