How the face sits in the head
The facial index, face width against head width, the neoclassical canons and how head shape bends the face, plus the landmarks every table is built from. Every figure attributed.
Contents
Range strips on one scale from 70 to 115 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 91 ± 5.9; Male 97 ± 5.8.
How to read the numbers
A list of 3 rows: Landmark choice; Population; Living subject vs dry bone. A green tick fills each box in turn.
Three things break most facial-measurement tables, and they are worth naming up front:
- Landmark choice. “Nose length” means
n-sn(nasion to subnasale, the vertical axis) to one author andn-prn(to the tip, a diagonal) to another. The two give different values on the same nose. Every table here names its landmarks. - Population. Adult means shift several millimetres between groups - more between groups than between the sexes in some cases. Where a figure is single-population it says so. Published reference ranges (“norms”) are tied to one population each and go stale; treat them as a frame, not a target.[1]
- Living subject vs dry bone. Skeletal studies (dry skulls, CBCT) report on bare bone; anthropometric studies measure skin over it. Soft tissue adds a layer over the bone that is thicker in some places than others.
Sex is treated here as the binary the source studies used (male/female). The honest summary is that region-by-region dimorphism is larger and more reliable than any whole-face measure - the robust differences are in the jaw, brow and nose, and the whole-face ratios (like fWHR) are the weakest signals of the lot.
How the face sits in the head
A scale from 75 to 100 index. Bands: 75 to 79.9, Hypereuryprosopic; 80 to 84.9, Euryprosopic; 85 to 89.9, Mesoprosopic; 90 to 94.9, Leptoprosopic; 95 to 100, Hyperleptoprosopic.
Landmarks: n nasion · gn gnathion · zy zygion · tr trichion (hairline) · en endocanthion · ex ectocanthion · al alare · go gonion · st stomion
The face measures in the feature pages only mean something against the head that contains them. Two families of ratio do the connecting work: the facial index (how long the face is for its width) and the face-to-head width ratios (how much of the skull's width the face actually fills).
Facial index - face length against face width
Facial index = (nasion → gnathion) ÷ (zygion → zygion) × 100. It is the standard classification of overall face form.
| Index | Class | Plain description |
|---|---|---|
| < 79.9 | Hypereuryprosopic | very broad, short |
| 80-84.9 | Euryprosopic | broad |
| 85-89.9 | Mesoprosopic | average, oval - where most people land |
| 90-94.9 | Leptoprosopic | long, narrow |
| ≥ 95 | Hyperleptoprosopic | very long, narrow |
Facial index classes and adult means[2]
Adult means in one 200-student Indian sample: males 88.15 ± 6.88, females 85.74 ± 5.26, full range 75.9-110.0 - i.e. the sexes straddle the meso/lepto boundary and individuals spread across the entire range.[2] A parallel upper facial index divides upper-face height by bizygomatic width instead, banding from hypereuryne (<44.9) up to leptene (>54.9).
Face width against head width
These are the ratios that actually change a silhouette. They are stated as fractions of each other rather than absolutes, so they survive scale.
| Ratio | Typical range | What moves the read |
|---|---|---|
| Bitemporal ÷ bizygomatic | 75-85% | below 75% sharpens the zygomatic arch; above 85% softens the upper contour[3] |
| Bigonial ÷ bizygomatic | 70-82% | F 70-78 · M 75-85; high = rectangular/square jaw, low = tapered heart shape[3] |
| Face width ÷ face height (fWHR family) | see the width-to-height section | a weak signal - prefer the raw widths above |
Facial width relationships
The neoclassical canons - useful scaffolding, poor law
A set of ratios handed down from classical art, still used as a first-pass scaffold. Stated as equations because that is how they are applied:
| Canon | Claims |
|---|---|
| Head halves | v-en = en-gn |
| Face thirds | tr-n = n-sn = sn-gn |
| Head quarters | v-tr = tr-g = g-sn = sn-gn |
| Fifths | en-en = ex-en |
| Eye = nose width | en-en = al-al |
| Mouth = 1.5 × nose | ch-ch = 1.5 × al-al |
| Nose = ¼ face | al-al = 0.25 × zy-zy |
| Ear = nose length | n-sn = sa-sba |
Neoclassical canons[4]
A systematic review of the canons[4] found canons 2, 6, 7 and 8 differ significantly between ethnic groups, and the greatest variability overall sits in forehead height, intraocular distance and nasal width - three of the canons' core assumptions. Use them as a starting grid to deviate from, not a target.
How head shape bends the face
- Brachycephalic head (short, broad): the vault is wide, so bizygomatic sits near head width and the face reads broad and flatter; the midface tends to look deeper-set because there is more transverse space around it.
- Dolichocephalic head (long, narrow): the vault is narrow, so the same cheekbone width occupies a smaller fraction of it; the face reads longer and slimmer, and features crowd closer to the midline.
- Because bizygomatic width tracks head breadth, widening the skull widens the face. A narrow face on a wide head reads pinched; a wide face on a narrow head reads as the cheekbones dominating.
- Vertical coupling is looser than horizontal. The face can be long or short on the same head breadth - which is exactly what the facial index in the facial index measures, independently of the cephalic index in the cephalic index. Head shape sets width; facial index sets length.
Landmark glossary
3 steps in order, lit one after another by a travelling dot: n, nasion, Bridge root, where nose meets forehead; prn, pronasale, Most anterior point of the nasal tip; sn, subnasale, Base of the columella, under the nose.
The points every measurement above is built from. Naming them is what makes two tables comparable.
| Abbrev. | Landmark | Where it is |
|---|---|---|
| n | Nasion | bridge root, where nose meets forehead |
| prn | Pronasale | most anterior point of the nasal tip |
| sn | Subnasale | base of the columella, under the nose |
| al | Alare | most lateral point of the nostril wing |
| ac | Alar crease | where the wing meets the cheek |
| en | Endocanthion | inner corner of the eye |
| ex | Ectocanthion | outer corner of the eye |
| p | Pupil centre | centre of the pupil in forward gaze |
| g | Glabella | smooth point between the brows |
| zy | Zygion | most lateral point of the cheekbone arch |
| go | Gonion | outer corner of the jaw angle |
| cdl | Condylion | top of the jaw joint (opposite gonion) |
| gn | Gnathion | lowest midpoint of the chin |
| pg | Pogonion | most anterior midpoint of the chin |
Sources
- Facial Type - population norms (Plastic Surgery Key). plasticsurgerykey.com/facial-type-3/
- An Anthropometric Study of the Facial Index (facial index classes; M 88.15 / F 85.74). pmc.ncbi.nlm.nih.gov/articles/PMC13399996
- Cheekbone prominence and midface width ratios (bitemporal/bizygomatic 75-85%; bigonial/bizygomatic 70-82%). facialharmonyai.com/blog/cheekbone-prominence-bizygomatic-ratio
- Historical Tools of Anthropometric Facial Assessment: the neoclassical canons (systematic review). Aesthetic Surgery Journal 2022. academic.oup.com/asj/article/42/1/NP1/6369423