Harmony · Side view · Facial Profile
Facial Convexity (Nasion)
The profile relationship of the nasal root, nose base and soft-tissue chin.
What is measured
The calculation
Oriented angle: nasion → subnasale → pogonion
Side view / Measurement guide
Follow the measurement
Dots mark the landmarks. Lines show how the measurement is taken.
In these guides, nasion means the nasal root, subnasale the nose base, and pogonion the most forward chin point. Frankfort refers to the direction from the ear-opening landmark to the lower orbital landmark.
Why it matters
This compares the upper and lower profile while excluding the projecting nose tip. The same angle can arise from different combinations of nasal-root, midface and chin position.
- Below 180°: the nose base is on the convex side of the upper-point-to-chin line.
- Above 180°: it lies on the concave side; 180° means the three points align.
Where the idea comes from
Clinical reference
Soft-tissue convexity is part of clinical profile analysis. FaceIQ uses the visible nasion, subnasale and pogonion and preserves the distinction between convex and concave arrangements. [1]
A worked example
170° describes a different profile bend from 180°. A reflex result of 190° is not the same as 170°, even though the small geometric angle matches.
Example values explain the calculation. They are not a target range and are not measurements of the schematic above.
Research & further reading
The sources below explain the history or related evidence. FaceIQ’s score weights and reference ranges are model settings; these papers do not collectively validate the scoring system.
[1] Holdaway · 1984
A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part IIExplains how lip, chin and skeletal relationships must be considered together, with a range of profiles compatible with balance.