What the term actually describes
Mentolabial angle is read at the labiomental sulcus — the fold between the lower lip and the chin — in side profile, between a line along the lower lip and a line along the front of the chin. Clinical cephalometric sources commonly cite 110 to 130 degrees as normal: narrower reads deeper and more sunken, wider reads flatter.
The fold itself is also the exact landmark chin projection uses as an informal test for whether a recessed mandible is hiding behind a chin that still projects. This page is about the angle formed there, not that separate projection test.
Why the "ideal" figure depends on whose face the study measured
One aesthetic-preference study rated 107 to 118 degrees most attractive, with up to 140 degrees called acceptable and anything outside roughly 98 to 162 degrees rated very unattractive. That already looks like a wide spread — but it's small next to how much reported population averages move:
- North American white male average: 113.5 degrees.
- African male average: 130.2 degrees.
- Asian male average: 134.8 degrees.
That's over a 20-degree spread between reported population averages for the same sex — wider than the gap between "most attractive" and merely "acceptable" in the preference study above. A figure sold as a universal ideal is often just one population's ordinary average, and another population's ordinary average can sit closer to a different study's "unattractive" cutoff.
An invisible factor a photo can't rule out
Orthodontic literature ties mentolabial angle changes to lower incisor inclination: proclined, tipped-forward lower front teeth push the lower lip outward and can shift the reading, independent of the underlying chin or jaw bone. The same literature ties it to mandibular advancement and genioplasty procedures.
None of that is visible in a side-profile photo, however clear. A photo shows the fold's shape; it can't show whether tooth angulation, orthodontic history, or a past jaw procedure put that shape where it sits — a blind spot camera angle can't fix, since even a perfect profile still can't see it.
Not the same trait as cervicomental angle or chin projection
All three are side-profile lower-face terms that get run together in forum shorthand, but they sit at different points in the same region:
- Mentolabial angle — the fold between the lower lip and the chin, above the chin point.
- Chin projection — how far forward the chin's own point sits, against a nose-to-chin reference line.
- Cervicomental angle — the chin-to-neck angle, below the chin, in the submental region.
A deep mentolabial fold can sit above a chin that still projects well, or above one that doesn't — the three traits move independently, which is exactly why forum threads about "fixing" one of them so often talk past each other.
Where this fits next to what Mogalytics actually reads
Mogalytics does not compute or display a mentolabial angle number. Its six-measurement composite reads live from a front-facing camera feed, and the closest measurement in the same lower-face family is jaw ratio — jaw height relative to face height, a frontal proportion rather than a profile fold angle.
Mogalytics makes no claim of parity between jaw ratio and mentolabial angle, or with any clinical or forum assessment of either.
Related reads
Mentolabial angle sits next to several other side-profile lower-face terms this site covers. If you're auditing the rest:
- Chin projection — the chin's own forward position, and the fold this page covers used as an informal test for it.
- Cervicomental angle — the chin-to-neck angle below the chin, a different structure again.
- Gonial angle — the bone angle at the jaw corner, unrelated to either soft-tissue fold.
- Chin-to-philtrum ratio — a vertical proportion in the same lower-face segment, read frontally instead of in profile.
- Ricketts E-line — the same nose-to-chin reference line chin projection is judged against.
- SNA/SNB angle — another profile angle where the real driver (skeletal position) needs an X-ray, not just a photo, to see.