Facial convexity angle: straight or convex profile
- Nerve
- Highlighted area
Quick facts
- Definition
- Profile angle formed by the glabella-subnasale and subnasale-soft tissue pogonion lines.
- Points used
- Soft tissue glabella, subnasale (where the columella meets the lip) and soft tissue pogonion (the most anterior point of the chin).
- Straight profile
- The three points sit almost aligned, with slight convexity.
- Convex profile
- The chin sits recessed relative to the midface; the angle closes.
- Concave profile
- The chin sits ahead of the base of the nose; the curve inverts.
- Relevance in HOF
- Guides the reading of the profile before planning chin, lips and jaw.
The facial convexity angle is a profile measurement formed by two lines: one from the glabella to the subnasale point (where the columella meets the upper lip) and another from the subnasale to the soft tissue pogonion, the most anterior point of the chin. It sums up in one number whether the facial profile is straight, convex or concave, that is, how the lower third sits relative to the midface.
How is the convexity angle measured?
The measurement is made on a standardized profile photo, with the head in natural position or aligned to a horizontal reference plane. The three soft tissue points are marked and the two lines drawn. There are two ways to express the result:
| Way of reading | How it works | Interpretation |
|---|---|---|
| Internal angle | Angle between the two lines, measured at the subnasale | Close to 180 degrees is a straight profile; the smaller, the more convex |
| Deviation of the line | How far the second line departs from the extension of the first | Close to zero is straight; larger positive values, more convex; negative, concave |
In the classic soft tissue cephalometric reference, the average deviation cited in adults is around 12 degrees of convexity, with a few degrees of variation. Values change with sex, age and ethnic background, so they serve as guidance, not as a target.
What does each type of profile usually indicate?
| Profile | What you see | Frequent causes |
|---|---|---|
| Straight or slightly convex | Glabella, base of the nose and chin almost aligned | Balance between maxilla and mandible |
| Markedly convex | Chin recessed relative to the base of the nose | Retrogenia, small or recessed mandible, projecting maxilla |
| Concave | Chin forward, midface recessed | Projecting mandible or recessed maxilla |
This reading is close to the concept of facial pattern used in dentistry and orthodontics. When the convexity has a marked skeletal origin, the case may call for orthodontic or surgical assessment, and not only an injectable procedure.
Why does it matter in HOF?
- Chin: in a convex profile from a recessed chin, projection of the chin is the first hypothesis to assess, since the lip alone does not correct convexity.
- Lips: enlarging the lips in a very convex profile can accentuate the impression of a projecting mouth. That is why the profile comes before lip volume.
- Nose: the dorsum and tip are not part of the angle, but they influence how the profile reads. The Ricketts line and the Steiner S line complement the analysis.
How does it show up in the assessment?
- Standardized profile photo, with no head rotation and with the lips relaxed.
- Comparison with the smile and the occlusion: the bite and the position of the teeth change the reading.
- Before and after record with the same framing.
The full assessment of the recessed chin is in retrognathic profile: assessment.
Also known as: profile convexity angle, G-Sn-Pg' angle, soft tissue facial convexity.
Frequently asked questions
What is the normal facial convexity angle?
It depends on the method and the population. In a classic soft tissue cephalometric reference, one measures how far the profile departs from a straight line, with an average of around 12 degrees in adults and a variation of a few degrees either way. Higher values indicate a more convex profile, and lower ones, a straighter or concave profile.
Is a convex profile a problem?
Not necessarily. Slight convexity is the usual shape of the human profile. The concern appears when the convexity is pronounced, usually from a recessed chin or a projecting maxilla, and the patient perceives an imbalance between nose, lips and chin.