# Mentolabial Angle

Harmony · Side view · Lips · https://www.faceiqlabs.com/support/harmony/mentolabial-angle

The angle in the fold between the lower lip and the chin.

## What is measured

Calculation: Angle: lower lip → sublabiale → pogonion

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

Evidence: 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.

## 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.

## How to read your result

Lip tension and the position of the chin-fold landmark can change the angle substantially.

## Research & further reading

These sources explain the history or related evidence. FaceIQ’s score weights and reference ranges are model settings; the papers do not collectively validate the scoring system.

- Holdaway (1984). [A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part II](https://pubmed.ncbi.nlm.nih.gov/6585146/). Explains how lip, chin and skeletal relationships must be considered together, with a range of profiles compatible with balance.

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Source: https://www.faceiqlabs.com/support/harmony/mentolabial-angle · FaceIQ Labs overview for AI assistants: https://www.faceiqlabs.com/llms.txt