Jaw and chin · Side photo

Chin projection

zero meridian

Checks whether the chin reaches the vertical through the bridge of the nose. Negative values mean the chin sits behind it.

How it's measured

Forward distance of the chin (pogonion) from the vertical through nasion, where vertical means square to the Frankfort plane, as a percentage of face height (nasion to menton). Positive when the chin is in front of the line. One decimal, because 1% is only about 1.2 mm.

Reference range

Male reference

0.0–3.9%

Female reference

0.0–4.3%

Source: Community facial analysis formula (public spreadsheet), top range: chin in line with or in front of the nasion vertical. That vertical is González-Ulloa's zero meridian (González-Ulloa M, Stevens E. Plast Reconstr Surg 1968;41:477-486). We cap the range at 5 mm in front, converted to % of face height.

In the score

Counts toward the score with weight 5 (Community formula point table: recession relative to the Frankfort plane, 5 points).

What changes it

• Needs a true side profile with the ear opening and the lower eye rim visible, so the head can be levelled before measuring.

One number, one feature

One measurement describes one detail in one photo. Pose, lens and expression move it, and every reference range is an average from limited samples.