The corrugator is a small muscle located just above each eyebrow, responsible for pulling your eyebrows inward and downward when you frown. Its full name is the corrugator supercilii, and it’s the primary muscle behind the vertical lines that form between your eyebrows. If you’ve ever heard the term at a dermatologist’s office, during a discussion about Botox, or in connection with migraine treatment, this is the muscle they’re referring to.
Where the Corrugator Sits
The corrugator originates from the bony ridge just above the inner corner of your eye socket, near the root of your nose. From there, its fibers run diagonally outward and slightly upward, threading beneath other facial muscles before inserting into the skin of the eyebrow roughly above the middle of the eye. This diagonal path is important: it means the muscle doesn’t just sit on the surface. The inner portion lies deep, close to the bone, while the outer portion blends into the frontalis (the broad forehead muscle) and sometimes has no clear boundary separating it from the surrounding tissue.
Sitting between the corrugator and the skin is the orbicularis oculi, the circular muscle you use to close your eyes. At the inner end, a layer of fascia separates these two muscles cleanly, but farther out toward the middle of the eyebrow, the corrugator’s fibers interweave with the muscles above and around it. This layered anatomy matters a great deal in both cosmetic and surgical contexts.
What the Corrugator Does
When you frown, concentrate, or squint in bright light, the corrugator pulls each eyebrow toward the center of your face. This creates the vertical creases between the eyebrows known as glabellar lines, sometimes called “elevens” because two parallel lines can resemble the number 11. The corrugator is the single most important muscle in generating those vertical creases.
It works alongside a smaller companion muscle called the procerus, which sits right between the eyebrows on the bridge of the nose. The procerus pulls the skin downward, creating horizontal wrinkles across the nose bridge. Together, these two muscles form the “glabellar complex,” the group of muscles responsible for the full range of frown-related facial movement.
The corrugator is strongly linked to negative emotional expression. It activates during anger, fear, sadness, and general displeasure. Research using facial electromyography (sensors that measure tiny electrical signals in muscles) shows that even very small activations of the corrugator, just a few microvolts, are enough to create temporary wrinkling between the eyebrows. Repeated frowning over years deepens these lines into permanent creases, which is one reason this muscle gets so much attention in cosmetic medicine.
Nerve Supply
The corrugator receives its instructions from the facial nerve, which controls most muscles of facial expression. What makes this muscle unusual is that it has a dual nerve supply. One set of signals arrives from the frontal branch of the facial nerve, passing deep to the orbicularis at the level of the eyebrow. A second set arrives through a pathway called the angular nerve, which is formed by branches of the zygomatic and buccal divisions of the facial nerve, traveling upward along the side of the nose. This redundant wiring means the muscle can still function even if one nerve pathway is damaged, a detail that matters during surgical procedures.
The Corrugator and Migraines
One of the more surprising connections in headache medicine involves the corrugator and migraine. The theory is that the muscle can compress sensory nerves running through the forehead region, and this compression may act as a trigger for migraine episodes in some people.
A landmark study followed 39 patients who had their corrugator muscle surgically removed (originally as part of a cosmetic forehead procedure) and who also had a history of migraines. Of those 39 patients, 31 (about 80%) reported that their migraines either improved significantly or disappeared entirely. Fifteen patients experienced complete elimination of their migraines over an average follow-up period of nearly four years. The results held for both migraines with aura and without. This research helped launch a broader interest in surgical nerve decompression as a treatment for certain migraine patients, particularly those whose headaches concentrate in the forehead area.
Cosmetic Treatment of the Corrugator
The corrugator is one of the most commonly treated muscles in cosmetic medicine. Botulinum toxin injections (widely known by brand names like Botox) work by temporarily blocking the nerve signals that tell the muscle to contract. With the corrugator relaxed, the skin between the eyebrows smooths out and vertical frown lines soften or disappear.
The standard approach uses a five-point injection pattern across the glabellar area. Two of those points target the corrugator on each side, and one targets the procerus in the center. The technique varies depending on where the needle is placed along the muscle. At the inner end, near the bone, injections go deep into the muscle bulk, just below the natural hairy brow. At the outer end, closer to the midline of the pupil, injections are placed superficially and as low as possible to avoid accidentally weakening the frontalis muscle above, which would cause the brow to drop.
This precision matters because the corrugator sits close to the levator palpebrae superioris, the muscle responsible for lifting the upper eyelid. If the injected toxin migrates beyond the corrugator, it can temporarily paralyze that eyelid muscle, causing the lid to droop. This side effect, called ptosis, occurs in roughly 3% of glabellar treatments and can appear anywhere from two to ten days after injection. It resolves on its own as the toxin wears off, but it’s the main reason practitioners pay close attention to injection depth and placement, especially along the outer tail of the corrugator.
Why the Corrugator Matters Beyond Cosmetics
Beyond wrinkle treatment and migraine surgery, the corrugator plays a role in emotional communication that researchers continue to find significant. Because it activates involuntarily during negative emotions, it serves as a reliable marker for how people feel, even when they’re trying to hide it. Psychologists and neuroscientists use corrugator activity measured through surface electrodes as an objective indicator of emotional response in studies on mood, empathy, and social perception.
The muscle also contributes to how others perceive your age and emotional state. Deep glabellar lines created by years of corrugator activity can make a resting face appear angry, worried, or tired, even when you feel none of those things. This disconnect between how you feel and how your face reads to others is one of the most common reasons people seek cosmetic treatment of the area.