The Upper Face: A Story of Muscles and Mastery
When you first begin to work with the muscles of the upper face, the frontalis is the area that will challenge you the most. It is highly variable—not just between individuals, but also in how men and women carry it. Some people have small foreheads, others long ones. You will see muscles that look like two separate plates, and muscles that appear as one solid sheet. In men, the frontalis often extends higher, sometimes beyond the hairline. And the aesthetic goals differ: with women you are typically aiming for a lift and a graceful arch, but a similar arch in a man can look unsettling. This is why you cannot rely on a single injection pattern for every forehead. You must learn a set of principles that allow you to treat any forehead, adapting to its unique anatomy.
Side effects in this region are common precisely because we almost never want to completely paralyze the entire frontalis. We need some movement to support the eyebrows. Over-treat the middle and you cause a medial brow ptosis along with a lateral lift; over-treat the lateral edge and you lose the arch, leaving the patient looking sad. Over-treat everything and the eyes will appear tired, and in patients with loose skin, you can even mimic a bilateral brow or eyelid ptosis. These aesthetic complications almost always come from a blanket approach—using the same dose or pattern for everyone.
My best advice for treating the frontalis starts with deciding where not to inject. Begin by marking a safety margin about two centimeters above the orbital rim to prevent brow ptosis. Also identify areas where there is no muscle—like an aponeurosis—and avoid wasting toxin there. Once you have drawn all the no-go zones, the area left to treat is usually small and manageable. The second key is to treat the first session as a journey, not a destination. On the first visit with a new patient, especially if their forehead is atypical, leave room for a top-up. It is far better to add a little more later than to correct an over-treatment like a dropped brow or lost arch.
The Corrugator Supercilii: The Glabellar Powerhouse
The corrugator supercilii—the muscle behind the "eleven" lines—is the next most important muscle in the upper face. Understanding its anatomy directly informs your injection technique. It runs from the periosteum medially, then travels through all the fat pads, and finally attaches to the dermis at the far lateral point. This path tells you to inject deep medially and gradually become more superficial as you move laterally. That approach minimizes side effects and maximizes product efficiency. The main side effect you want to avoid is eyelid ptosis, which happens because as you go laterally you get closer to the supratrochlear foramen—the exit point for an artery and nerve. If you inject too deeply there, toxin can spread to the levator palpebrae muscle. By staying superficial laterally, the fat pad acts as a buffer and greatly reduces that risk.
You also need to assess the vector—the direction of pull—of each patient's corrugators. Some people frown flatly, while others have a strong downward vector. This vector is why we almost always treat the corrugator together with the frontalis. If you treat the frontalis alone, it lifts the brows, but leaves the untreated corrugator pulling downward. The result is a much scarier, angrier expression—something patients often complain about when their partner says they look cross all the time. So as a rule of thumb, treat them together. But with experience, you may find a patient who has no significant downward pull and a very small corrugator, and you can safely skip it. Always show the patient the vector so they understand why you recommend both areas.
The Depressor Supercilii: A Small but Notable Player
There is a little muscle called the depressor supercilii, located more medially than the corrugator and pulling straight down. Some consider it part of orbicularis oculi rather than a separate muscle. Clinically, it is often treated inadvertently when you inject the medial corrugator. But if a patient still pulls down after you have treated that area well, consider that the depressor supercilii might be the culprit—it is more superficial than the corrugator, so a slightly more superficial injection can help. It is not a powerful muscle, just one to keep in mind.
The Procerus: The Nose Bridge Muscle
The procerus muscle runs over the bridge of the nose and pulls the glabella downward. It is hugely variable—sometimes so small it is almost absent, other times the dominant muscle in the glabellar complex. Do not fall into the habit of injecting the same number of units every time. Assess each patient individually by asking them to frown, and if they cannot, show them the movement in a mirror or perform it yourself. You can also feel the muscle by placing a finger on the area and sensing the direction of pull. In patients where the procerus is strong, you may want to put 10–12 units into it and less into the corrugator. Procerus can also affect the shape of the nose: if a patient has a bump that bends when they frown, consider using toxin to relax the procerus before doing a non-surgical rhinoplasty. That gives the filler a still surface to bed in on and can help the result last longer.
Orbicularis Oculi: The Crow's Feet and Beyond
The orbicularis oculi is the circular muscle around the eye, responsible for most crow's feet lines (though some come from the zygomatic muscle). Because it is a ring, it has multiple vectors pulling in different directions. This complexity shows up when you treat lateral canthal lines: if you relax that area, you may uncover a medial pull that was previously balanced. Some patients develop a strong medial vector from over-treatment, which looks unnatural. The trick is to use less toxin and consider other modalities like dermal fillers instead of chasing lines endlessly.
Orbicularis oculi is also in a tug-of-war with the frontalis—while frontalis lifts the brow, orbicularis pulls it down. Relaxing orbicularis slightly can give a subtle brow lift, and can even rescue a brow ptosis caused by over-treating frontalis. But be careful: orbicularis oculi plays a role in the Duchenne smile—the genuine, eye-crinkling smile that signals true emotion. Over-treat it and the smile looks flat, and in older patients the cheek may appear to sag because the muscle provides essential support. A little too much toxin in the lower part can even affect the zygomatic muscles, causing smile asymmetry that looks like a stroke—one of the most distressing complications.
The single best technique for this area is to inject superficially. Most clinicians are used to inserting a needle at least halfway, but for orbicularis oculi you only need about a millimeter and a half—just enough to sit on top of the muscle. That minimizes bruising and creates a shield that protects the deeper zygomatic muscles from accidental weakening. Also, do not go too inferior. By respecting the depth and staying superficial, you avoid the most upsetting side effects while still achieving excellent results.
These are the muscles of the upper face: frontalis, corrugator, depressor supercilii, procerus, and orbicularis oculi. Each one demands respect for its variability and its interactions with the others. When you treat them with assessment, caution, and a willingness to take the journey gradually, you will make better decisions and help your patients understand why your approach is tailored to them.