The orbicularis oculi is the sphincter muscle of the eyelid, forming an elliptical ring around the orbit divided into orbital, palpebral, and lacrimal portions. The palpebral portion produces gentle blinking and voluntary eye closure, while the orbital portion generates forceful eye closure such as during a sneeze. Blinking distributes the tear film across the cornea — essential for corneal health — occurring approximately 15 times per minute.
| Origin | Medial orbital margin, medial palpebral ligament, and lacrimal groove |
|---|---|
| Insertion | Forms a complete elliptical ring around the orbit, with the palpebral portion in the eyelid and the orbital portion encircling the bony orbit |
| Nerve Supply | Temporal and zygomatic branches of the facial nerve (CN VII) |
| Blood Supply | Ophthalmic artery (supraorbital and supratrochlear branches) |
| Actions | Gentle voluntary eyelid closure and blinking; Forced eyelid closure and winking |
|---|
The lacrimal portion of the orbicularis oculi draws the lacrimal puncta medially into contact with the eye during blinking, creating a pumping action that moves tears through the nasolacrimal drainage system. Failure of this pump mechanism in facial nerve palsy contributes to epiphora despite normal tear production.
Facial nerve palsy produces lagophthalmos (inability to close the eye), exposing the cornea to desiccation, infection, and ulceration — a sight-threatening complication that requires urgent lubricating eye drops, moisture chamber goggles at night, and lid weights or tarsorrhaphy for persistent palsy. Blepharospasm is an involuntary rhythmic orbicularis oculi contraction producing disabling eye closure treated with botulinum toxin injection into the palpebral portion.
The orbital portion of the orbicularis oculi is palpable encircling the orbital rim as a thin muscular band during forceful eye closure. The palpebral portion is within the eyelid and is not separately palpable.
Inability to close the eye from facial nerve palsy exposing the cornea to desiccation and ulceration, requiring urgent lubrication and eye protection with lid weight insertion or tarsorrhaphy for persistent cases.
Involuntary disabling orbicularis oculi contractions treated with botulinum toxin injection into the palpebral portion every 3 to 4 months.
