In short. The glabella is the deepest folding point on the face. What decades of folding do to the skin, and why the muscle rung comes before the surface rung.
Key points
- A glabellar crease has a moving part and a fixed part.
- The moving part is the fold made by muscle contraction and it flattens when the muscle is quiet.
- The fixed part is the groove left in the skin, and it does not.
The creases between the brows become permanent features earlier than lines anywhere else on the face. This is the deepest folding point on the face, and the reason is a combination of where the skin is, what it is tied to, and how often it is folded.
Skin that is tethered to bone
Over most of the face, skin sits on a layer of fat and connective tissue that lets it slide and spring back when it is pushed into a fold. Between the brows the skin is bound down to the underlying bone by the structures around the brow fat pad. It cannot slide out of the way, so when the muscles beneath it shorten, the skin does not stretch and recover. It creases in the same place, in the same direction, every time.
Muscles that are almost never at rest
The corrugator and the procerus are among the hardest working muscles in the face. They contract during concentration, during reading, in bright light, when the eyes are dry or the prescription is wrong, and through a great deal of ordinary expression. A muscle that fires thousands of times a day produces thousands of folds a day in skin that cannot slide away from them.
A fold becomes a groove
At first the crease appears only while the muscle is working and vanishes when the face relaxes. Over years the repeated folding, together with the loss of collagen that sun exposure and time produce, leaves a groove in the skin itself. From that point the line is present with the face completely at rest, and the muscle is no longer the only thing producing it.
Two components, two treatments
A glabellar crease has a moving part and a fixed part. The moving part is the fold made by muscle contraction and it flattens when the muscle is quiet. The fixed part is the groove left in the skin, and it does not. Everything about the order of treatment follows from that division.
What the depth means for the order of treatment
The rung that reduces the muscle pull comes first, because it stops the folding that is deepening the groove. Resurfacing comes after it rather than instead of it, because it works on what is left in the skin, and that work is wasted on a crease that is being refolded daily.
Three expectations worth correcting
- A crease that is visible at rest will not disappear; it usually softens, and how much depends on the skin.
- Treating the surface while the fold continues daily loses most of the surface result.
- A face that cannot frown at all is not the same as a face without a crease, and it does not look better.
The anatomy behind the direction of the crease is set out in why frown lines are vertical. What the moving component can be treated with is covered in botulinum toxin for frown lines, and the categories that work on the fixed component are described in resurfacing the etched glabellar line.
Frequently asked questions
Why do these lines appear at rest before lines elsewhere on the face?
Because the skin there is tied down rather than free to slide. Over most of the face, skin sits on a layer that lets it move and recover when it is pushed into a fold. Between the brows it is tethered to the bone by the structures around the brow fat pad, so it creases in the same place every time, and the groove forms earlier than it does where skin can move.
Does the groove keep getting deeper once it is there?
It deepens slowly with time and sun, because the skin continues to lose the collagen that lets it recover and the muscle continues to fold it. The rate is gradual rather than dramatic, and it is not changed by whether the line is treated cosmetically. It is influenced by sun exposure, which is the part that can be acted on.
If the muscle is quiet for a while, does the groove fill in?
Partly, and in a limited way. While the muscle is not folding the skin, the crease is not being reinforced and it usually looks softer. That is a real change and it is not the same as the groove being removed, because the physical change in the dermis is still there. It reappears as the movement returns.
Risks & Limitations
- Relaxing the corrugator and the procerus also lifts the medial brow, and in a brow that already sits high that lift can become the complaint rather than the result.
- A drooping eyelid, double vision, or difficulty swallowing, speaking or breathing after an injection needs emergency care rather than a wait-and-see approach.
- Resurfacing carries a risk of pigment change and, rarely, of scarring, and its result is judged weeks after the last session rather than on the following morning.
- No rung removes a crease that is established in the skin. A line that is visible at rest usually softens, and any statement that promises more should be treated with suspicion.
When to Seek Care
- Difficulty breathing, chest pain, or difficulty swallowing or speaking after an injection needs emergency care immediately.
- A drooping eyelid, double vision, or an eye that will not close fully after treatment.
- Weakness or numbness on one side of the face, or a brow that has dropped on one side.
- A crease that has appeared or deepened over weeks rather than years, or any change in vision on one side.
References & Further Reading
- American Society of Plastic Surgeons (ASPS) — procedure and safety guidance
- National Institute for Health and Care Excellence (NICE, UK) — relevant guidance
- Cochrane Library — systematic reviews
- Chinese Medical Association Plastic Surgery Branch — clinical guidance
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.