Harmony · Side view · Lips
Mentolabial Angle
The angle in the fold between the lower lip and the chin.
What is measured
The calculation
Angle: lower lip → sublabiale → pogonion
Side view / Measurement guide
Follow the measurement
Dots mark the landmarks. Lines show how the measurement is taken.
In these guides, nasion means the nasal root, subnasale the nose base, and pogonion the most forward chin point. Frankfort refers to the direction from the ear-opening landmark to the lower orbital landmark.
Why it matters
It describes how the lower lip transitions into the chin contour. A more closed fold and a smoother, more open transition can occur even with similar overall chin projection.
- Lower: a more acute fold angle.
- Higher: a more open lip-to-chin transition.
Where the idea comes from
Clinical reference
Soft-tissue profile analysis examines the lip–chin fold as part of the surrounding contour. FaceIQ uses three visible photo landmarks to describe it. [1]
A worked example
A fold measuring 110° is more closed than one measuring 140°. This does not indicate the fold’s physical depth in millimeters.
Example values explain the calculation. They are not a target range and are not measurements of the schematic above.
Research & further reading
The sources below explain the history or related evidence. FaceIQ’s score weights and reference ranges are model settings; these papers do not collectively validate the scoring system.
[1] Holdaway · 1984
A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part IIExplains how lip, chin and skeletal relationships must be considered together, with a range of profiles compatible with balance.