Chin projection vs a bony reference plane (zero meridian, etc.)what a photo can give, and how we take it.
Chin–lip direction from the profile and chin share of the lower face from the front, with the masculinity read on the chin and the beard call that follows.
What we report
Chin–lip direction from the profile and chin share of the lower face from the front, with the masculinity read on the chin and the beard call that follows.
Why not the clinical number itself
Gonzalez-Ulloa's zero meridian drops a vertical from nasion with the head in Frankfort horizontal. It requires a lateral view AND a reproducible reference plane (FH varies ±4.6° between individuals). Around eight mutually inconsistent published methods for chin position exist (Goode, Merrifield, Silver, Legan, Burstone, Riedel, Steiner, Byrd) — which is itself evidence that none is a ground truth.
Sources
- Ahmad & Rohrich 2014, Aesthet Surg J — origin of the zero meridian — doi.org/10.1177/1090820X14539974
Ratios of near-coplanar frontal distances, angles relative to the interpupillary line, and skin appearance — each with an error bar, each against a population you choose. Start an analysis or read the methodology.
How every bone-level measurement is taken here · all insights