Levator palpebrae superioris and ptosis
- Muscle
- Highlighted area
Quick facts
- Origin
- Lesser wing of the sphenoid, at the back of the orbit, above the optic canal.
- Insertion
- Through an aponeurosis, on the front surface of the upper tarsus and the eyelid skin, where it forms the eyelid crease.
- Action
- Lifts the upper eyelid and keeps the eye open.
- Innervation
- Oculomotor nerve (cranial nerve III); the superior tarsal muscle, which is smooth, receives sympathetic innervation.
- Relevance in facial harmonization
- Spread of toxin to it causes eyelid ptosis, a known unwanted effect of toxin in the glabella and forehead.
The levator palpebrae superioris is the muscle that opens the eye. It lies inside the orbit, above the eyeball, and lifts the upper eyelid. In HOF it matters for one main reason: when botulinum toxin injected in the glabella or forehead spreads to it, the eyelid droops, a condition called eyelid ptosis.
Where is it and how is it built?
The levator arises at the back of the orbit, from the lesser wing of the sphenoid bone, just above the optic canal. It runs forward above the superior rectus muscle and, near the orbital rim, passes under the superior transverse ligament (Whitnall's ligament), where it becomes a tendinous sheet, the aponeurosis. The aponeurosis inserts on the front surface of the upper tarsus and sends fibers to the skin, forming the upper eyelid crease.
| Structure | Type | Innervation | Role |
|---|---|---|---|
| Levator palpebrae superioris | Skeletal muscle | Oculomotor nerve (cranial nerve III) | Main lift of the eyelid |
| Superior tarsal muscle (Müller's) | Smooth muscle, under the levator | Sympathetic | Additional lift, about 1 to 2 mm |
| Orbital septum | Fibrous sheet | Not applicable | Separates the orbit from the superficial layers |
| Frontalis muscle | Muscle of facial expression | Facial nerve | Lifts the eyebrow, not the eyelid |
The difference in innervation explains two practical facts. The levator is not a muscle of facial expression and is not a toxin target in HOF. And the superior tarsal muscle, being sympathetic, responds to alpha-adrenergic agonist eye drops, which can be used to ease temporary toxin-related ptosis, by prescription and at the discretion of the licensed professional.
Why does it matter in facial harmonization?
Toxin injected near the upper orbital rim can cross the orbital septum and reach the levator. The risk is cited mainly in toxin in the glabella, in the corrugator region, and with larger dilution volumes, which increase the area of spread.
For full management, see ptosis after botulinum toxin.
How do you tell eyelid ptosis from a drooping eyebrow?
They are different conditions, with different causes, and patients often call both a "droopy eye":
- Eyelid ptosis: the edge of the upper eyelid drops and covers more of the iris. Usual cause: spread to the levator.
- Eyebrow drop: the eyebrow sits lower and weighs on the eyelid, but the eyelid margin stays in place. Usual cause: excessive blocking of the frontalis, especially in someone who was already compensating for a low eyebrow by lifting the forehead.
In the prior assessment, observe the height of the eyelid margin relative to the pupil, eyelid and eyebrow asymmetries, and whether the patient uses the frontalis to keep the eyes open. All of this should be photographed before any injection into the forehead lines and the glabella.
Also called: levator palpebrae superioris, eyelid lifter muscle.
Frequently asked questions
Why did the eyelid droop after botulinum toxin?
Usually because some of the toxin spread to the levator palpebrae superioris, inside the orbit. It tends to appear a few days after the injection and to be temporary, resolving in weeks. The patient should go back to the professional who injected.
What is the difference between a drooping eyelid and a drooping eyebrow after toxin?
In eyelid ptosis, the edge of the eyelid drops and covers more of the iris. In eyebrow drop, the eyebrow sits lower and weighs on the eyelid, but the eyelid margin stays in place. The causes and management are different.