Insights · Nose · Measurement

Alar base width : intercanthal distance

Nose width at the alar base as a multiple of the distance between the inner eye corners.

Confidence
Tier A · tight interval
Unit
ratio (dimensionless)
Landmarks
al_R, al_L, en_R, en_L
CI floor
± 0.03
alarWidth / dist(en_R, en_L)
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Illustration · on your scan the same lines are drawn on your own photo

How to read it

Below the mean

the alar base is narrow relative to the intercanthal distance for the reference group.

Near the mean

alar base width sits close to the reference mean relative to the intercanthal distance.

Above the mean

the alar base is wide relative to the intercanthal distance for the reference group. Note that this is the single measurement most inflated by short camera distance — Ward et al. (2018) measured a ~30% apparent widening of the nasal base at 12 inches versus 5 feet — so the capture-distance estimate above should be read alongside this value.

The neoclassical claim: Alar width = ICD (orbitonasal canon)

92% of Saudi males and the large majority of African and East Asian adults have a nose wider than their intercanthal distance. The canon describes a minority of humans.

Conformity in published samples: na white 41% · east asian 19% · middle east m 7% · middle east f 33%

Reference values by population

Reference populationFemale (mean ± SD)Male (mean ± SD)nSource
North American White0.987 ± 0.0951.048 ± 0.1132326Farkas 1994/2005 (NA White young adults) prov.
East Asian1 ± 0.11.055 ± 0.1618Farkas 2005 (Chinese/Japanese/Vietnamese/Thai pooled); Jayaratne 2012 (Southern Chinese, n=103) prov.
South Asian1.063 ± 0.1091.123 ± 0.12210Farkas 2005 (Indian); Metgudmath 2022 prov.
African / African diaspora1.194 ± 0.1251.261 ± 0.134300Farkas 2005 (African-American, Zulu, Angolan) prov.
Middle Eastern1.048 ± 0.1081.092 ± 0.116348Farkas 2005 (Turkish, Iranian, Egyptian); Al-Sebaei 2015 (Saudi, n=168) prov.
Hispanic / Latino1.063 ± 0.1121.121 ± 0.123120Farkas 2005 (Mexican-American) prov.
Not specified — show pooled1.059 ± 0.1461.117 ± 0.1523922Unweighted pool of the six groups above 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
  • Farkas, Hreczko, Kolar & Munro (1985). Vertical and horizontal proportions of the face in young adult North American Caucasians: revision of neoclassical canons. Plast Reconstr Surg 75(3):328–338. pubmed.ncbi.nlm.nih.gov/3883374/
  • Farkas, Katic & Forrest (2005). International Anthropometric Study of Facial Morphology in Various Ethnic Groups/Races. J Craniofac Surg 16(4):615–646. doi.org/10.1097/01.SCS.0000171847.58031.9E
  • Al-Sebaei (2015). The validity of three neo-classical facial canons in young adults originating from the Arabian Peninsula. Head Face Med 11:4. doi.org/10.1186/s13005-015-0064-y
  • Ward, Ward, Fried & Paskhover (2018). Nasal Distortion in Short-Distance Photographs: The Selfie Effect. JAMA Facial Plast Surg. doi.org/10.1001/jamafacial.2018.0009

Related: how bone-level measurements are taken from a photo · methodology · all insights