Orbicularis oculi
Musculus orbicularis oculi
MuscularSuperficial musclesHeadLeft and right
View left in 3D View right in 3D
- What it is
- Concentric sphincter around the eye: an orbital part lying on the bony orbital margin and a thin palpebral part within the eyelids, anchored medially to the medial palpebral ligament and lacrimal bone.
- Function
- Closes the eyelids — gently in blinking (palpebral part) or tightly when squeezing the eyes shut (orbital part) — and helps pump tears into the lacrimal sac.
- Size
- Ring about 5 cm across and ~1 cm wide, 1–2 mm thick.
- Clinical note
- Facial nerve palsy prevents eye closure and risks corneal drying; "crow's feet" wrinkles run at right angles to its lateral fibres.