Orbicularis oculi muscle: anatomy and crow's feet
- Muscle
- Highlighted area
Quick facts
- Location
- Around the orbit, covering the eyelids and the bony frame of the eye.
- Parts
- Orbital (peripheral), palpebral (pretarsal and preseptal) and lacrimal (deep, next to the lacrimal sac).
- Action
- Closes the eye, from a gentle blink to a tight squeeze, and lowers the eyebrow, especially in the lateral portion.
- Innervation
- Temporal and zygomatic branches of the facial nerve.
- Relevance in HOF
- Forms crow's feet and takes part in the glabellar complex; a frequent target for botulinum toxin.
- In Harmy
- The periorbital area is close to the Tear Trough and Glabella points.
The orbicularis oculi is the circular muscle that surrounds the orbit and closes the eye. It is responsible for blinking, for forceful eyelid closure and, in its lateral portion, for pulling the eyebrow down. In HOF it is the muscle behind crow's feet, the fan-shaped lines at the outer corner of the eye, and one of the pieces of the balance that defines eyebrow position.
Where is it and how is it built?
The muscle arises from the medial side of the orbit (medial palpebral ligament, frontal process of the maxilla and nasal part of the frontal bone) and its fibers circle the eye. The Terminologia Anatomica describes three parts:
| Part | Where it is | Action |
|---|---|---|
| Orbital | Peripheral, over the bony frame of the orbit | Forceful closure; lowers the eyebrow; forms crow's feet |
| Pretarsal palpebral | Over the tarsus of the eyelids | Blinking and gentle closure; helps keep the eyelid against the eye |
| Preseptal palpebral | Over the orbital septum | Blinking and gentle closure |
| Lacrimal | Deep, behind the lacrimal sac | Assists tear drainage |
In the lower eyelid, the transition between the palpebral and orbital parts lies close to the orbicular retaining ligament, which anchors the muscle to the bone. Innervation comes from the temporal and zygomatic branches of the facial nerve, which reach the muscle through its deep and lateral surface.
Why does it matter in HOF?
The orbicularis oculi is involved in three frequent topics:
- Crow's feet: contraction of the lateral orbital part forms the dynamic wrinkles of the outer corner, which over time can become static wrinkles. It is one of the classic indications for botulinum toxin.
- Eyebrow position: the lateral portion depresses the tail of the eyebrow. Reducing its strength can let the frontalis act with less opposition and slightly change the lateral shape of the eyebrow.
- Glabella: the medial fibers join the corrugator, the procerus and the depressor supercilii in frowning.
How does it show up in the assessment?
- Spontaneous smile: shows the fan of crow's feet and how far down the cheek it extends.
- Squeezing the eyes shut: reveals the extent of the orbital part.
- Lower eyelid snap test: gently pulling the lower eyelid down and releasing it assesses tone; a slow return suggests laxity and calls for caution.
- At rest: separates lines that appear only in motion from those already visible at rest.
- Prior dry eye: ask and record it, because toxin can make it worse.
For the full anatomy of the area, see the periorbital area.
Also called: orbicularis oculi, orbicular muscle of the eyelids, crow's feet muscle.
Frequently asked questions
What is the function of the orbicularis oculi muscle?
It closes the eye. The palpebral part handles blinking and gentle closure; the orbital part handles forceful closure and lowers the eyebrow. The lacrimal part helps drain tears.
Which muscle forms crow's feet?
The lateral orbital part of the orbicularis oculi. When it contracts, especially when smiling and squinting, it folds the skin at the outer corner and forms the fan-shaped lines.