Corrugator, procerus and brow depressor in toxin treatment

The glabella is the area between the eyebrows and, in botulinum toxin treatment, it is one of the most treated territories of the face. It is also one of the most poorly explained: people speak of "the frown muscle" as if it were a single one. In fact, the frown is the result of a complex of at least three muscles, each with a different direction of pull, and understanding those differences helps predict how the brow will behave.

This page is a review of applied functional anatomy, with no dose, point or injection technique. Management and product are the decision of the qualified professional, according to the label and the rules of their professional council.

What is the glabellar complex?

It is the group of muscles that move the medial region of the brow and the root of the nose, producing frowning, drawing together and lowering. The three main ones are the corrugator supercilii, the procerus and the depressor supercilii. The orbicularis oculi, in its orbital part, is a neighbor that contributes to eye closure and to brow position.

All of these muscles act in opposition to the frontalis, the brow elevator. The shape and position of the brow at rest and in expression result from this interplay of forces, which is why changing one side of the balance affects the other.

Each muscle, one direction

This table is a simplification. Anatomy varies between patients, the fibers blend together and the contraction pattern changes from person to person.

Corrugator

It arises from the bone in the region of the superciliary arch and inserts into the brow skin, above the pupil. Its contraction brings the brows together and forms the vertical folds. It is the muscle most associated with the expression of worry, anger or concentration.

Procerus

It is a small muscle at the root of the nose that joins the frontalis. When it contracts, it lowers the skin between the brows and forms transverse folds. It contributes to the "furrowed brow" look and to the "V" shape many patients show.

Depressor supercilii

It sits near the medial corner of the eye and acts by lowering the medial part of the brow. In some cases it is considered a bundle of the orbicularis or the corrugator, and whether it is a separate muscle is debated. Functionally it matters because it contributes to medial brow drop.

How the glabellar complex shapes the brow

The brow is a balance point between forces that lift (frontalis) and forces that pull down (glabellar complex and orbicularis). A few practical consequences:

• Predominance of the depressors: a lower brow, a tired or serious look.
• Weakening of the glabellar complex: the frontalis may gain freedom and lift the medial part, giving the gaze a more open look.
• Weakening of the frontalis without treating the complex: the brow may drop, and the heavy-eyed look increases.
• Muscle asymmetries: a stronger side pulls more, which shows in the lines and in the height.

The topic is explored further in botulinum toxin in the eyebrow and botulinum toxin in the frontalis muscle, and the overview of fundamentals is in botulinum toxin: fundamentals.

Frowning patterns

Watching the patient frown, before any decision, reveals patterns that guide the conversation. Common descriptions:

1. "11" pattern: vertical lines predominate, with strong corrugators.
2. "U" or "V" pattern: a combination of corrugators and procerus, with a rounder or more triangular shape.
3. "Omega" pattern or with a central point: procerus contraction is more marked.
4. Asymmetric pattern: one side contracts more, producing uneven lines and a different brow position.
5. Pattern with predominant medial depressors: the brow drops more in the medial third.

These labels are teaching descriptions, and each service may use its own terms. The point is that looking, without assuming, shows who owns each movement.

Risks specific to the area

The glabella is an area requiring great care, both because of the toxin and because of the vascular anatomy. Points to know:

• Brow ptosis: brow drop from weakening of the frontalis or imbalance of the group.
• Eyelid ptosis: drooping of the upper eyelid from toxin spreading to the levator palpebrae. See ptosis after botulinum toxin.
• "Angry" or "Mephisto" brow: excessive lateral lift with the medial part held down, covered in the glossary under Mephisto sign.
• Asymmetry: uneven response of the muscles.
• Headache: reported by some patients after the injection.
• Bruising and local pain.
• With filler in the area (which is different from toxin), the glabella is a high vascular risk zone, and glabellar vascular occlusion is a topic of its own.

When the result does not come as expected

Lack of effect, a short effect or an unexpected brow shape have causes that go beyond a "weak product". They may involve muscle pattern, antibodies, storage, technique or expectation. See botulinum toxin non-response and storing botulinum toxin.

When there is a complaint about the brow, the reasoning involves reassessing the balance between the frontalis and the depressors, the time since the injection and the previous position. Brow position is a starting point: very low brows at rest are a warning sign for any frontalis treatment.

How to talk to the patient

The patient often asks to "remove the lines" and rarely understands that the face is a system. Explaining in concrete terms helps.

How Harmy relates to the glabella

In Harmy, the Glabella is one of the marking points. The app works with a symbolic unit of intensity and shows an illustrative projection based on the frontal photo. The simulation does not reproduce muscle dynamics, so it does not show the frown or the effect on brow position.

The app's role here is to support the visual conversation, not to replace the dynamic assessment done in the clinical exam.

Evolution timeline

Quick review

The glabellar complex is an example of how small muscles control big impressions. Understanding that the corrugator, procerus and depressor supercilii pull in different directions, and that all of them interact with the frontalis, is what makes the assessment of the frown more precise than "removing the wrinkle".