In short. The crease under the lower lip does more to make a chin read as natural than the chin point does. How a forward, downward or rotated segment changes it.
Key points
- A profile photograph taken from the side shows both.
- The question worth asking is whether the crease under the lip still sits where it should once the chin is in its new position, because that is the feature other people read without knowing they are reading it.
The crease between the lower lip and the chin is called the labiomental fold. It is a normal feature of every face, and it does more to make a chin look natural than the position of the chin point does. A chin that projects correctly but has lost its fold reads as artificial, and a chin with a deep or high fold reads as heavy even when the projection is right.
The fold is a soft-tissue feature, but a genioplasty changes it. Moving the segment forward tends to flatten the fold, because the tissue in front of the bone is carried forward and the crease is drawn out. Moving the segment down tends to move the fold upward relative to the chin point and can deepen it. Rotating the segment changes the angle at which the lower lip meets the chin.
This is why a chin operation is planned against the fold rather than against the chin point alone. Where the fold is already shallow, a forward movement can flatten it further and the chin can lose definition. Where the fold is deep, a forward movement can improve it by taking up some of the depth. The same movement, in two faces, has opposite effects on the feature that decides how natural the result looks.
Judge the fold, not the chin point
A profile photograph taken from the side shows both. The question worth asking is whether the crease under the lip still sits where it should once the chin is in its new position, because that is the feature other people read without knowing they are reading it.
The fold also changes with the rest of the face. A nose that is being altered changes how the profile reads above the fold, and the position of the lower lip changes it from above. Patients who judge a chin only from the chin point are often surprised by how much the crease moved.
A shallow fold can be deepened and a deep fold made shallower, but neither can be decided after the bone has healed. That is the argument for discussing the crease before the operation rather than after it, and for asking the surgeon what the proposed movement does to it. A patient who can say where the crease sits now, and where it would sit afterwards, has hold of the question that matters most.
How the fold can end up wrong
- It is flattened by a forward movement in a face where it was already shallow.
- It is deepened or displaced by a downward movement that lengthens the lower face.
- It is left where it was while the chin moves away from it, so the crease sits too high or too low.
This article does not discuss treatments for the skin around the crease, because lines in the skin and the position of a fold are different problems. What is described here is a change in contour produced by moving bone.
Frequently asked questions
Why does the crease matter more than the position of the chin?
Because a crease that sits wrongly is what makes a chin look operated on. The eye reads the angle between the lower lip and the chin before it reads how far the chin projects, so a chin in the right position with a flattened or displaced fold still looks wrong, while a chin with a good fold reads as natural even when the projection is modest.
Will my crease get deeper if the chin is brought forward?
It usually gets shallower, because the tissue in front of the bone is carried forward and the crease is drawn out. That is welcome where the fold was deep, and a problem where it was already shallow, because the chin can lose definition. This is one of the reasons the fold is assessed before the movement is chosen rather than after.
Can the crease be adjusted after the operation if it looks wrong?
Not by anything simple. The crease is produced by the position of the bone and the soft tissue over it, so changing it means changing the bone, which means another operation. That is why the fold is treated as part of the plan rather than as something to be corrected later if it turns out badly.
Risks & Limitations
- Numbness of the lower lip and chin is expected after a cut in the jaw; it usually improves over months and may not return completely.
- A second operation in the same bone carries a higher chance of numbness that does not recover fully.
- The change is fixed once the bone heals, and reversing it means cutting again rather than removing something.
- Final results are judged at three months or later, and more fairly at a year, not in the first weeks.
When to Seek Care
- Difficulty breathing or chest pain — seek emergency care immediately.
- Fever with swelling, redness or discharge over the jaw, which may mean infection around the plates.
- A numb area of the lip or chin that is getting larger rather than smaller after the first weeks.
- Loss of movement in the lower lip, or an incision inside the mouth that opens.
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.