The orbicularis oris muscle is the primary muscle responsible for closing the lips.
This circular muscle surrounds the mouth and its contraction brings the lips together. Several sources confirm this:
- ScienceDirect: "Contraction of this muscle closes and protracts the lips." https://www.sciencedirect.com/topics/neuroscience/orbicularis-oris-muscle
- Physiopedia: "Closing the lips: orbicularis oris muscle." https://www.physio-pedia.com/FacialMuscles-_Lower_Group
- Kenhub: "Closing the lips: orbicularis oris muscle." https://www.kenhub.com/en/library/anatomy/the-facial-muscles
- Cleveland Clinic: "Orbicularis oris, a circle of muscle around your mouth that closes or purses your lips." https://my.clevelandclinic.org/health/body/21672-facial-muscles
While other muscles contribute to lip movements and expressions, the orbicularis oris is the key player in the act of simply closing the lips. Think of puckering your lips – that’s the orbicularis oris in action.
