Chin projection vs a bony reference plane (zero meridian, etc.)
what a photo can give, and how we take it.

From the profile, which way the chin sits relative to the lips. From the front, how much of the lower face the chin takes up. The masculinity read on the chin and the beard call follow from those two.

Also searched as recessed chin, weak chin and chin projection.

Why the textbook version needs more than a photo
lateral
Canthion reports
Photographic equivalent

What we report

From the profile, which way the chin sits relative to the lips. From the front, how much of the lower face the chin takes up. The masculinity read on the chin and the beard call follow from those two.

Frankfort horizontalzero meridian:a vertical from nasion,head in Frankfortchin projection
The zero meridian drops a vertical from nasion with the head in Frankfort horizontal, and chin projection is how far the chin sits in front of it. Both lines need a lateral view and a reproducible reference plane.

Why not the clinical number itself

Gonzalez-Ulloa's zero meridian drops a vertical from nasion with the head in Frankfort horizontal. It needs a lateral view, and it needs a reference plane that can be reproduced (FH varies ±4.6° between individuals). Around eight mutually inconsistent published methods for chin position exist: Goode, Merrifield, Silver, Legan, Burstone, Riedel, Steiner, Byrd. That there are eight of them is itself evidence that none is a ground truth.

Sources
What we measure instead

Ratios of near-coplanar frontal distances, angles relative to the interpupillary line, and skin appearance. Each comes with an error bar, and each is placed against a population you choose. Start an analysis or read the methodology.

What the report gives you insteadPhiltrum length : chin height

Same question, different measurement: what the clinical version needs, and what a photograph can give instead.

Nasofacial angle, and any profile angle taken against a planelateral · what a photo can giveRicketts E-line, Steiner S-line, Holdaway H-linelateral · what a photo can giveGonial anglebony · what a photo can giveRamus : mandibular body ratiobony · what a photo can giveOrbital vector / infraorbital rim positionbony · what a photo can giveOgee curve scoreinvented · what a photo can give

What is measured instead

Intercanthal distance : palpebral fissure lengthEyes · tier AAlar base width : intercanthal distanceNose · tier AMouth width : alar base widthLips · tier AUpper : lower vermilion heightLips · tier APhiltrum length : chin heightLower face · tier APalpebral fissure height : lengthEyes · tier A
← Facial width-to-height ratio (fWHR)Fitzpatrick type / Individual Typology Angle from RGB →

How every bone-level measurement is taken here · methodology · glossary · all 35 insight pages