Brow apex position
Horizontal position of the highest point of the eyebrow, expressed from 0 (above inner canthus) to 1 (above outer canthus).
How to read it
the brow peaks medially (a flatter or centrally-arched brow).
the brow apex sits over the outer third of the eye, the position textbook teaching describes.
the brow peaks far laterally.
This measures brow HAIR, which is plucked, threaded, dyed, tattooed and drawn on. It is not a biological measurement and should not be read as one.
Reference values by population
| Reference population | Female (mean ± SD) | Male (mean ± SD) | n | Source |
|---|---|---|---|---|
| North American White | 0.72 ± 0.12 | 0.72 ± 0.12 | — | Textbook convention (apex over lateral limbus). No population anthropometry exists for this. Provisional. prov. |
| East Asian | 0.72 ± 0.12 | 0.72 ± 0.12 | — | Textbook convention (apex over lateral limbus). No population anthropometry exists for this. Provisional. prov. |
| South Asian | 0.72 ± 0.12 | 0.72 ± 0.12 | — | Textbook convention (apex over lateral limbus). No population anthropometry exists for this. Provisional. prov. |
| African / African diaspora | 0.72 ± 0.12 | 0.72 ± 0.12 | — | Textbook convention (apex over lateral limbus). No population anthropometry exists for this. Provisional. prov. |
| Middle Eastern | 0.72 ± 0.12 | 0.72 ± 0.12 | — | Textbook convention (apex over lateral limbus). No population anthropometry exists for this. Provisional. prov. |
| Hispanic / Latino | 0.72 ± 0.12 | 0.72 ± 0.12 | — | Textbook convention (apex over lateral limbus). No population anthropometry exists for this. Provisional. prov. |
| Not specified — show pooled | 0.72 ± 0.12 | 0.72 ± 0.12 | — | Textbook convention (apex over lateral limbus). No population anthropometry exists for this. Provisional. prov. |
Where these numbers come from
Transcribed from the cited anthropometric literature; SDs of ratios are propagated conservatively (independence assumed). Entries marked prov. await line-by-line audit against the primary tables — see the norm provenance note.
Why every value has an error bar
Every value Canthion reports carries a 1σ uncertainty propagated from MediaPipe Face Mesh's published accuracy (3.96% of inter-ocular distance mean absolute error per landmark, Kartynnik 2019). For a typical 300 px inter-pupil photo that is ≈12 px per landmark, which is why small ratios and angles get wide intervals. A number without an interval is a number pretending to be more precise than it is.
References
- Clinical norm: lateral canthus sits ~2–4 mm superior to the medial canthus (≈ +4° to +7° at ICD ≈ 30 mm). Evaluation of Eyelid Function and Aesthetics (Plastic Surgery Key, textbook chapter). plasticsurgerykey.com/evaluation-of-eyelid-function-and-aesthetics/
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