Orbicularis oculi !

The orbicularis oculi is the ring of muscle around the eye and inside the eyelids; it closes the eye to blink or squeeze, and fails to close it in Bell's palsy.

Official name: Orbital part of orbicularis oculi

See in 3D →

Opens in the Durgical app, no sign-up needed.

What it is

A ring of muscle around the eye and inside the eyelids.

What it does

Closes the eye gently (blinking) or tightly (squeezing); it cannot close the eye in Bell's palsy.

Key facts

Origin: Medial orbital margin, medial palpebral ligament, lacrimal bone
Insertion: Skin around the orbit, lateral palpebral raphe
Action: Closes the eyelids (palpebral: blink; orbital: squeeze)
Nerve: Facial nerve (CN VII): temporal and zygomatic branches
Blood supply: Facial artery branches

Relations

Superficial: Thin eyelid skin, with almost no fat between them; thicker skin and fat over the orbital part
Deep: Orbital septum and tarsal plates of the eyelids; in the upper lid the levator palpebrae superioris; at the orbital rim the corrugator supercilii and suborbicularis fat
Medial: Medial palpebral ligament and the lacrimal sac of the tear drainage system, which the lacrimal part wraps behind
Lateral: Lateral palpebral raphe and the zygomatic bone
Above: Frontalis and the brow
Below: Origins of the levator labii superioris and zygomaticus minor and major

How to find it

Asked to close the eyes tightly, the ring contracts around the orbit, wrinkling the skin into crow's feet at the outer corner; a gentle blink moves only the lid part.

Examination

Closing the eyes tightly against the examiner's fingers: the lid opens easily on a weak side, and the eyelashes stay visible (lashes not buried)
Corneal reflex: touching the cornea gives no blink on the side of a facial nerve lesion, while the other eye still blinks (consensual), which separates it from a V1 lesion
In a central lesion the eyes still close almost fully; in Bell palsy the eye cannot close

On imaging

Thin, so it is judged clinically rather than on images. On CT or MRI of the orbit it lies in the eyelids just under the skin, in front of the orbital septum. That septum is the key boundary: CT separates preseptal cellulitis, swelling only in front of it, from orbital cellulitis behind it, which needs urgent treatment and may hide an abscess. Ultrasound helps with eyelid lumps.

Clinical notes

Exposure keratitis is the main risk in facial palsy; lid taping, lubrication, an upper-lid weight or tarsorrhaphy protect the cornea
Paralysis of the lower lid lets it sag outward (paralytic ectropion) and tears run down the cheek, because the lacrimal pump fails
Hemifacial spasm usually starts as twitching around the eye; it is often caused by a vessel pressing on the facial nerve near the brainstem
Benign essential blepharospasm, a focal dystonia of this muscle, is treated with botulinum toxin injection

Development

A second pharyngeal arch muscle: the facial nerve enters this arch's muscle mass early and is pulled along as the mass spreads around the eye, which is why the eyelid closer depends on VII and not on III.

Test yourself

Think of the answer, then tap the question to see it.

What is the role of the orbicularis oculi in the corneal reflex?

It is the motor limb: touch is carried by V1 and the blink is made by the facial nerve through the orbicularis oculi.

What are the three parts of the orbicularis oculi and their actions?

Orbital (tight squeeze), palpebral (gentle blink) and lacrimal (pumps tears into the lacrimal sac).

What happens to the eye when the orbicularis oculi is paralysed?

The eye cannot close (lagophthalmos) and the cornea dries; on trying to close, the eyeball rolls up (Bell phenomenon).

Why do tears run down the cheek in lower-lid paralysis of the orbicularis oculi?

The lower lid sags outward (paralytic ectropion) and the lacrimal pump fails.

Add to my cards (4)

Educational information, not medical advice. For any symptom, see a health professional.

Its names

Official Latin (TA2): pars orbitalis musculi orbicularis oculi TA2 2070
Official Spanish (DeCS): Músculo orbicular del ojo DeCS D005152
English (TA2): Orbital part of orbicularis oculi

Facial nerve (VII)

Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Head and Neck: Orbicularis Oculi Muscle; Anatomy of the Human Body (20th ed.): Development of the Muscles (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain.

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.

Orbicularis oculi highlighted on the Durgical 3D model