Cheekbones and the width-to-height ratio

By Mackenzie Bowes · mackenzie@mackenziebowes.com · @_mackenziebowes on X

Bizygomatic width by sex and population, what varies in the zygomatic region, and why the facial width-to-height ratio is a weak sex signal. Every figure attributed.

A scale from -0.4 to 0.4 d. Marks: US Army, d = -0.24 at -0.24; Meta-analysis, d = 0.11 at 0.11; US Army, d = +0.16 at 0.16; Athletes, d = 0.31 at 0.31. Effect size d, male minus female; the US Army sample gives either sign depending on how height is defined.

Sex differences in facial width-to-height ratio are small and inconsistent.

Cheekbones - the zygomatic region

Range strips on one scale from 115 to 160 mm, each with a mean tick, a solid band at plus or minus one standard deviation and a pale band at plus or minus two. Female 133.8 ± 5.6; Male 142.6 ± 6.2.

Cheekbone width by sex (ANSUR II, n≈6,068).

Landmarks: zy zygion (most lateral point of the zygomatic arch) · fmo frontomalare orbitale

The zygomatic bones set the widest point of the face (bizygomatic width) and define the malar “apple” under the eye. They are the single most dimorphic width measure in the face when body size is controlled for - a much stronger signal than the width-to-height ratio it feeds into (the width-to-height section).

Measure	Female	Male	Sex gap	Note
Mean width	133.8 ± 5.6 mm	142.6 ± 6.2 mm	+8.8 mm	US Army personnel (ANSUR II), mean age ≈ 30, n≈6,068[1]
Standardised dimorphism	d = 1.39 raw · d = 1.07 body-size-adjusted[1]	very large	strong marker

Bizygomatic width (Zy-Zy), adults

What actually varies

Overall breadth - the main dial; male arches sit further laterally, giving the wider, flatter midface.
Anteroposterior (AP) projection - how far the cheek stands off the face in profile. “Primary determinant of the malar apple.”
Arch orientation - more front-facing vs more lateral sweep; the classic trait differences in how “flat” the face reads front-on.
Muscle over bone - masseter and temporalis bulk thicken the visible cheek independently of the bone, and scale with body mass.

Population spread is real and large: in a 3,000-subject Chinese survey, face width was 147.6 mm in men and 140.1 mm in women, with jaw width 118.5 / 114.5 and face length 117.0 / 109.7 - several millimetres wider than the US Army figures above, which come from a young, mostly male military sample and not a population census.[3]

Facial width-to-height ratio

fWHR = bizygomatic width ÷ upper-facial height. Definitions vary: the height runs from the upper lip to the brow in some studies and to the top of the eyelids in others, so values are not interchangeable across studies.

A dimensionless proxy for how “wide and square” a face reads. It is popular and heavily studied, but it is a weak dimorphism signal - and the reason matters for anyone using it as a masculinity dial.

Sample	Female	Male	Effect
17,607 passport images, across the lifespan[6]	overall mean 2.18 ± 0.18 (not re-checked)	-	male larger only in young adulthood; direction reverses after age 48
Meta-analysis, n = 10,853[4]	-	slightly larger	d = 0.11, small
Commonwealth Games athletes, n = 3,481[5]	1.92	1.98	d = 0.31; not significant after controlling for body size
US Army personnel, n = 6,068[1]	-	-	mixed: d = −0.24 or +0.16, depending on how height is defined

fWHR reference values

The important caveat. fWHR’s dimorphism is genuinely small: a meta-analysis of 10,853 people found d = 0.11.[4] In the athlete sample the difference vanished once body size was controlled,[5] and in the 6,068-person army sample the effect flipped sign depending on how the height was measured (d = −0.24 or +0.16). Measured directly, bizygomatic width in that same sample is highly dimorphic (d = 1.39, and still 1.07 after adjusting for 92 body measurements).[1] In practice: use cheekbone width, not fWHR, as your masculinity pointer - fWHR will move the wrong way as often as the right one.

Age matters too. In the lifespan study the male advantage appears only in young adulthood and reverses after about 48, with women recording the larger ratio.[6] A single masculinity dial on fWHR is wrong for older characters.

Sources

Caton & Dixson (2022). Bizygomatic width is highly sexually dimorphic when adjusting for allometry. Biology Letters. pmc.ncbi.nlm.nih.gov/articles/PMC9554718/
Using data-driven phenotyping to investigate the impact of sex on 3D human facial surface morphology. pmc.ncbi.nlm.nih.gov/articles/PMC10335371
Measurement and analysis of human head-face dimensions (n=3,000; face width, jaw width, face length, nose protrusion). pubmed.ncbi.nlm.nih.gov/18727867
Geniole, Denson, Dixson, Carré & McCormick (2015). Evidence from Meta-Analyses of the Facial Width-to-Height Ratio as an Evolved Cue of Threat. PLOS ONE (sex difference d = .11, n = 10,853; fWHR related to BMI, r = .31). pmc.ncbi.nlm.nih.gov/articles/PMC4504483/
Kramer (2015). Facial Width-to-Height Ratio in a Large Sample of Commonwealth Games Athletes. Evolutionary Psychology (n = 3,481; men 1.98, women 1.92, d = 0.31; difference not significant after controlling for body size). pmc.ncbi.nlm.nih.gov/articles/PMC10430000/
Tracking sexual dimorphism of facial width-to-height ratio across the lifespan: implications for perceived aggressiveness. Royal Society Open Science (2022; 17,607 passport images; male larger only in young adulthood, reversed after age 48). doi.org/10.1098/rsos.211500