# Gonion-to-Mouth Line

Harmony · Side view · Jaw · https://www.faceiqlabs.com/support/harmony/gonion-to-mouth-line

The vertical difference between the constructed jaw corner and the mouth corner.

## What is measured

Calculation: (Constructed gonion y − mouth-corner y) × photo scale

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 locates the jaw corner within the height of the face. Two jaws with a similar corner angle can have different vertical positions relative to the mouth.

- Negative: the jaw-line intersection is above mouth-corner level.
- Positive: it is below mouth-corner level.

## Where the idea comes from

Evidence: FaceIQ adaptation. This is a FaceIQ photographic construction. Clinical profile analysis provides context, but the cited work does not validate this exact landmark formula or its scoring range.

## A worked example

A jaw intersection 10 units below the mouth corner at 0.2 estimated mm per unit gives +2 mm.

Example values explain the calculation. They are not a target range.

## How to read your result

The app uses an intersection of extended jaw lines, not simply a single marked jaw-corner dot. Smiling moves the mouth reference.

Millimeters are approximate: FaceIQ scales the photo using an assumed 190 mm hairline-to-chin height, so these are estimates, not calibrated physical measurements.

## 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.

- Farkas et al. (2005). [International anthropometric study of facial morphology in various ethnic groups/races](https://pubmed.ncbi.nlm.nih.gov/16077306/). Documents variation in facial dimensions across sampled populations. Descriptive measurements explain variation; they do not establish an attractiveness score.

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Source: https://www.faceiqlabs.com/support/harmony/gonion-to-mouth-line · FaceIQ Labs overview for AI assistants: https://www.faceiqlabs.com/llms.txt