Muscle · Head

Orbicularis oculi

Musculus orbicularis oculi

The ring of muscle that encircles the eye and closes it. It works in two gears: a fine inner part in the eyelids that blinks and spreads tears across the eye without you noticing, and a broader outer part over the orbital rim that screws the eye shut and pulls the eyebrow down. It is also a small pump for tear drainage, which is why weakness of this muscle causes a watering, exposed eye rather than simply a droopy lid.