Jaw & chin measurement
Ramus-to-Mandible Ratio
Height of the jaw’s vertical branch (tragion to jaw angle) relative to the length of the jaw body (jaw angle to menton). A short ramus tends to go with a steep jaw; a long ramus with a strong, square lower face. The usual ideal of about 0.6–0.8 measures the ramus from the jaw joint (condylion), which sits roughly 6 mm below tragion; measured from tragion the same jaw reads about 0.08 higher, so the range here is shifted by that much. Because the shift is derived rather than published, this measurement counts less in the overall score.
At a glance
- Ideal
- 0.67–0.85
- Unit
- ratio (no unit)
- Weight in the overall score
- 6
- Area
- Jaw & chin
How it is measured
|Po–Go| ÷ |Go–Me|
- Po Tragion (porion) — The top of the tragus — the small flap in front of the ear canal. With orbitale it defines the Frankfort horizontal.
- Go Gonion (jaw angle) — The corner of the jaw, where the lower border turns upward toward the ear.
- 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 −10 (below 0 where the original tier sheet takes points away) at the far end of the worst tier.
| Tier | Range | Rating |
|---|---|---|
| T1 Ideal | 0.67–0.85 | 9.5–10 |
| T2 Near ideal | 0.64–0.67 or 0.85–0.88 | 7.2–9.5 |
| T3 Mild deviation | 0.62–0.64 or 0.88–0.90 | 5.2–7.2 |
| T4 Moderate deviation | 0.57–0.62 or 0.90–0.95 | 3.4–5.2 |
| T5 Significant deviation | 0.52–0.57 or 0.95–1.00 | −5 to 3.4 |
| T6 Severe deviation | < 0.52 or > 1.00 | −10 to −5 |