Muscle
Orbicularis oculi
Protective muscle for eyelid closure
High-yield
CN VII powers eyelid closure. Weakness can leave part of the cornea exposed, increasing the risk of surface drying and injury.
Overview
Orbicularis oculi surrounds the eyelids and orbital opening. Its palpebral fibers produce gentle closure and blinking; its orbital fibers tighten the lids more forcefully. Blinking helps maintain the tear-covered surface of the eye.
Reference facts
- Origin
- Medial orbital margin, medial canthal tendon and adjacent lacrimal attachments
- Insertion
- Eyelid and periorbital tissues, including the lateral palpebral raphe and tarsal regions
- Action
- Palpebral fibers close the lids gently; orbital fibers produce forceful closure
- Innervation
- Temporal and zygomatic branches of the facial nerve (CN VII)
- Blood supply
- Branches of the ophthalmic and facial arterial networks, with superficial temporal contributions
Clinical correlation
Bell’s phenomenon is upward, often outward, eye rotation during attempted lid closure. It occurs in healthy people and becomes easier to see when facial weakness prevents complete eyelid closure; it is not specific to Bell palsy.
Frequently asked questions
What does the orbicularis oculi do?
Palpebral fibers close the lids gently; orbital fibers produce forceful closure.
What nerve innervates the orbicularis oculi?
The orbicularis oculi is innervated by the temporal and zygomatic branches of the facial nerve (CN VII).
Where does the orbicularis oculi attach?
Origin: Medial orbital margin, medial canthal tendon and adjacent lacrimal attachments. Insertion: Eyelid and periorbital tissues, including the lateral palpebral raphe and tarsal regions.
What is the blood supply of the orbicularis oculi?
Branches of the ophthalmic and facial arterial networks, with superficial temporal contributions.