Short Lower Third: Low Chin and What to Do

"My chin is too low, it looks like I have no chin." The concern comes up in different words: a short face below, a flat chin, a "baby face", a mouth too close to the chin. In all of them, the patient is talking about the vertical proportion of the lower third. It is a topic where HOF has a limited role and where honesty about the limits makes a difference in the relationship with the patient.

This page covers the height of the lower third and the role of the chin. For the projection concern, see small chin and recessed chin. For assessing the third as a whole, complete lower third in the plan.

How the lower third is measured

The lower third runs from the subnasale to the menton, and the stomion (the point where the lips meet) divides it into two parts. In a classic division, the upper lip takes up about one third, and the lower lip with the chin takes the remaining two thirds. This ratio is a teaching reference, not a rule, and it varies between people and populations, as discussed in facial proportions vary between populations.

To say the third is short, the comparison is with the other two thirds of the patient's own face and with the overall picture. A small lower third in a harmonious face may be constitutional and not call for treatment. Standardized photography, from the front and in profile, is the basis of the conversation. The division of the plan is detailed in one-third to two-thirds proportion in the lower third.

Where the sense of a low chin comes from

Almost every case has more than one cause. A patient with a deep bite often also has a poorly projected chin, and the lower lip gains visual weight. When the dominant cause is skeletal or dental, HOF can only compensate. See deep bite and recessed chin and short face and recessed chin.

What chin filler can do

Volume in the chin can add projection and, depending on the design, part of the apparent length of the chin. This improves how the profile reads and, in some faces, the proportion of the lower third. The limits, however, are clear: the volume is in soft tissue, it does not change the position of the bone or the bite, and the gain in height is small.

If the concern is height and the plan is only to project forward, the face still looks short from the front, and the profile may end up with a "pushed out" chin. The reverse also happens: adding height without projection can create a chin that looks elongated and unsupported. The useful question is which dimension is more deficient: height or projection. More about the procedure in chin filler.

The role of the lower lip

In many patients, the lower third looks short because the lower lip is full and the mentolabial sulcus is deep, which reduces the visible area of the chin. Reducing the weight of the lower lip is not a common option with injectables, but filling the chin to balance the whole may be. The reading is done in profile and in three-quarter view. See drooping lower lip for the related concern.

The mentolabial sulcus matters too: in some cases, a small softening of the sulcus gives the chin back some apparent height. The topic is covered in hyaluronic acid in the mentolabial sulcus.

When to refer

Deciding to refer is not a defeat. If the third is short because of a significant deep bite, tooth wear or loss of vertical dimension, the dentist and the orthodontist are part of the plan. In cases of evident skeletal deformity, a surgical assessment is part of the counseling. HOF comes in as a complement, and the patient needs to understand that it does not replace structural correction. See orthodontics and profile change and orthognathic surgery and harmonization.

How to organize the plan

1. Measure the lower third on a standardized photo and compare it with the other thirds.
2. Classify the dominant cause: bone, bite, soft tissue or lip.
3. Refer when there is a relevant dental or skeletal component.
4. If chin volume is indicated, plan a conservative amount and assess from the front and in profile.
5. Reassess with comparison photos and discuss adjustments.

Safety

The chin is a lower-risk area than the midface, but the submental artery and the inferior labial artery are nearby, along with the mental nerve. Possible complications include swelling, bruising, asymmetry, nodules, paresthesia and, rarely, vascular occlusion. Keep hyaluronidase available and review the anatomy of the mental nerve and the submental artery.

How to use Harmy in this conversation

Harmy simulates the Chin point on a frontal photo. Because the projection uses only the frontal photo, it does not show the profile, which is an important limitation in chin concerns: the patient will see the effect from the front, but not from the side. This should be said before showing the result.

For the conversation, explaining the chin to the patient and I want a bigger chin provide support.

Questions to test your reasoning

What to record in the patient record

Record the measurements, the front and profile photos, the dominant cause, what was explained about the limits, any referrals made and the specific consent for the chin. Note the patient's expectation in their own words. For the photo standard, see standardized clinical photography.

Common mistakes

The first mistake is photographing with the chin out of position, which changes every measurement. The second is treating height with product when the problem is the bite. The third is promising the patient a structural change that soft tissue does not deliver.

Summary for the decision

A short lower third is a concern about vertical proportion with skeletal, dental and soft tissue causes. Measure with standardized photos, classify the cause, refer when there is a dental or skeletal component and, if the chin is treated, use a conservative amount and assess from the front and in profile. HOF complements and does not replace bone or the bite. Act at the discretion of the qualified professional, in line with the rules of their professional board, without promising results.