Mental protuberance: the bony relief of the chin
- Nerve
- Highlighted area
Quick facts
- Definition
- Triangular bony elevation on the anterior surface of the mandible, at the midline, that forms the bony chin.
- Structures
- Includes the mental symphysis, the lateral mental tubercles and the pogonion as the most anterior point.
- Variation
- Size and shape change between people, sexes and populations.
- Relevance in facial harmonization
- Defines the starting point of the chin contour; filler acts on soft tissue, not on bone.
The mental protuberance is the triangular bony elevation located at the front and bottom of the mandible, at the midline. It gives the chin its bony base: over it lie the fat, muscle and skin that, together, produce the contour the patient sees in the mirror.
What structures make it up?
The protuberance has a characteristic design, with parts that the literature describes separately:
| Part | Description |
|---|---|
| Mental symphysis | Line where the two halves of the mandible join, fusing in the first years of life |
| Mental tubercles | Two lateral reliefs that form the base of the triangle |
| Pogonion | Most anterior point of the bony chin, used in profile measurements |
| Mental foramen | Lateral opening through which the mental nerve exits |
Muscles insert onto it, such as the mentalis, which attaches to the region just below the incisor teeth and lifts the skin of the chin.
Why does it vary so much?
The size, width and projection of the protuberance depend on genetics, sex and age. In general, male chins are wider and squarer and female chins narrower and rounder, but there is a lot of overlap. Some patients have well-projected bone and little soft tissue; others, the reverse.
This variation explains why the same volume of product behaves differently in different patients. When the bone is poorly projected, the picture may be retrogenia or microgenia, and the assessment must separate what is bone from what is soft tissue.
What can and cannot facial harmonization do?
Fillers and other techniques act on the soft tissue over the bone. They can change the perception of chin projection and length in selected cases, but they do not replace the structural change that a genioplasty provides. The difference between the two paths should be clear in the conversation with the patient.
The main cautions in the area are the presence of the mental nerve, which gives sensation to the lower lip and chin, and of vessels such as the submental artery. When hyaluronic acid is injected, hyaluronidase must be available.
Also called: chin protuberance, bony chin, mental eminence.
Frequently asked questions
Why do two patients have such different chins?
Because the mental protuberance varies in size, width and projection, and the thickness of the soft tissue over it also changes. The sum of the two defines the chin that is seen.