Profile measurement
Lower Third Proportion
The lower facial third (subnasale to menton) as a share of glabella-to-menton height. Equal middle and lower thirds give 0.50; lower values mean a short lower face, higher values a long one.
At a glance
- Ideal
- 0.49–0.54
- Unit
- ratio (no unit)
- Weight in the overall score
- 7
- Area
- Profile
How it is measured
Height Sn→Me ÷ height G→Me (perpendicular to FH)
- G Glabella — The most forward point of the forehead, on the midline between the eyebrows.
- Sn Subnasale — The point where the underside of the nose meets the upper lip.
- Me Menton — The lowest point of the chin.
Ideal range and tiers
Each value falls into a tier (T1 = ideal). Comfortably inside T1 the rating is 10, easing to 9.5 at the edges of the ideal range; beyond it the rating falls with the deviation — fastest in the first tiers outside the ideal — down to 0 at the far end of the worst tier.
| Tier | Range | Rating |
|---|---|---|
| T1 Ideal | 0.49–0.54 | 9.5–10 |
| T2 Near ideal | 0.47–0.49 or 0.54–0.56 | 6.7–9.5 |
| T3 Mild deviation | 0.45–0.47 or 0.56–0.58 | 4.3–6.7 |
| T4 Moderate deviation | 0.43–0.45 or 0.58–0.60 | 2.1–4.3 |
| T5 Severe deviation | < 0.43 or > 0.60 | 0–2.1 |
Related measurements
References
- Legan HL, Burstone CJ. Soft tissue cephalometric analysis for orthognathic surgery. J Oral Surg. 1980;38(10):744–751.
- Farkas LG. Anthropometry of the Head and Face. 2nd ed. Raven Press; 1994.