Ramus to Mandible Ratio: How FaceIQ Labs Measures It

Key facts

• Formula: tragus-to-jaw-line-intersection length ÷ intersection-to-chin-vertical length.
• It is a side-view jaw measurement in FaceIQ Labs' Harmony guides.
• A longer side segment or a shorter lower-border segment increases the ratio.
• Worked example: a 60-unit constructed side segment and a 90-unit lower segment give 0.67; the example is not a target range.
• The photo's tragus-based segment is a proxy, not the anatomical condyle-to-gonion ramus length.
• FaceIQ constructs the intersection from photo border lines and ends the lower segment at the chin's vertical line.
• In FaceIQ Labs' guides, Frankfort refers to the direction from the ear-opening landmark to the lower orbital landmark.
• FaceIQ Labs says its score weights and reference ranges are model settings, and the cited paper does not validate the scoring system.
• Harmony is weighted roughly 60% from the front photo and 40% from the side photo; side photos are standardized to the Frankfort horizontal plane during landmarking.

What does the ramus to mandible ratio measure?

FaceIQ Labs' ramus to mandible ratio is a side-view jaw measurement in its Harmony analysis. It divides the tragus-to-jaw-line-intersection length, a constructed side segment, by the intersection-to-chin-vertical length, a constructed lower segment. The guide's schematic labels these two segments A and B and is not drawn to scale.

Why does the ramus to mandible ratio matter?

The ratio compares the upright portion and the lower portion of the jaw outline in a FaceIQ Labs side-view photo. A longer side portion and a shorter lower-border portion both increase the ratio. The guide describes what moves the ratio up or down but gives no ideal value or target range.

What makes the ratio higher or lower?

• Higher: a longer constructed side segment relative to the lower segment.
• Lower: a shorter constructed side segment relative to the lower segment.
• A shorter lower-border segment also raises the ratio.
• FaceIQ Labs' guide states no preferred direction.

What does a worked example of the calculation look like?

In FaceIQ Labs' worked example, a 60-unit constructed side segment and a 90-unit constructed lower segment give a ratio of 0.67, because 60 divided by 90 is about 0.67. The guide says example values only explain the calculation. They are not a target range and are not measurements of the guide's schematic.

Does the ratio measure true jaw bone anatomy?

No. FaceIQ Labs states that the photo's tragus-based segment is a proxy, not the anatomical condyle-to-gonion ramus length. The ratio is built from landmarks visible in a photo and constructed lines, so it approximates the jaw outline rather than directly measuring the jaw bone.

Where does the ramus to mandible ratio come from?

FaceIQ Labs describes the ratio as its own adaptation. Comparing mandibular segments follows anatomical proportion analysis, while FaceIQ constructs an intersection from photo border lines and ends the lower segment at the chin's vertical line. Farkas et al. (2005) is listed as related reading on facial dimension variation.

How does the ratio fit into FaceIQ Labs' scoring?

FaceIQ Labs scores uploaded face photos from 0 to 10 on four pillars: Harmony, Angularity, Dimorphism and Features. The ramus to mandible ratio is one of the Harmony measurement guides, a side-view jaw measurement. Harmony is weighted roughly 60% from the front photo and 40% from the side photo, with side photos standardized to the Frankfort horizontal plane.

What research does FaceIQ Labs cite for this ratio?

FaceIQ Labs cites one source on this guide: Farkas et al. (2005), 'International anthropometric study of facial morphology in various ethnic groups/races.' It documents variation in facial dimensions across sampled populations. FaceIQ Labs says descriptive measurements do not establish an attractiveness score, and that its weights and reference ranges are model settings.

Which related FaceIQ Labs jaw guides exist?

• Gonial Angle
• Mandibular Plane Angle (the guide before this one in the sequence)
• Gonion-to-Mouth Line (the guide after this one in the sequence)
• Chin Position Relative to the Frankfort Plane

Frequently asked questions

What formula does FaceIQ Labs use for the ramus to mandible ratio?

The tragus-to-jaw-line-intersection length divided by the intersection-to-chin-vertical length. The intersection is constructed from photo border lines, and the lower segment ends at the chin's vertical line.

Is a higher or lower ramus to mandible ratio better?

FaceIQ Labs' guide says only that a longer side segment or shorter lower segment raises the ratio and the reverse lowers it. It states no preferred direction, and its 0.67 example is not a target range.

Is the ramus to mandible ratio the same as clinical ramus length?

No. FaceIQ Labs states that the photo's tragus-based segment is a proxy, not the anatomical condyle-to-gonion ramus length.

Which FaceIQ Labs pillar includes the ramus to mandible ratio?

It is part of the Harmony pillar, one of four pillars scored 0–10 alongside Angularity, Dimorphism and Features.

What is the worked example for this ratio?

A 60-unit constructed side segment and a 90-unit constructed lower segment give 0.67. FaceIQ Labs says the example only illustrates the calculation.