View source for Facial convexity

{{Short description|Profile angle through forehead, subnasale, and chin}}
{{Infobox term
| image          = Cephalometric radiograph.JPG
| caption        = Lateral cephalometric radiograph (Commons). Facial convexity is a profile angle on a tracing, not a rating-app score.
| alt            = Lateral cephalometric radiograph
| name = Facial convexity
| also = facial convexity angle, G–Sn–Pog, angle of facial convexity
| field = Anatomy
| related = [[Chin]]; [[Riedel's line]]; [[Ricketts E-line]]; [[Pogonion]]; [[Midface]]
}}
'''Facial convexity''' is how the side profile bends from the forehead through the base of the nose to the chin. The usual soft-tissue construction is the angle '''G–Sn–Pog''' (or G–Sn–Pg′): [[glabella]], subnasale, and soft-tissue [[pogonion]], with the vertex at subnasale.<ref name="godt">{{cite journal |last1=Godt |first1=Arnim |last2=Müller |first2=Anne |last3=Kalwitzki |first3=Mirjam |last4=Göz |first4=Gernot |title=Angles of facial convexity in different skeletal Classes |journal=European Journal of Orthodontics |volume=29 |issue=6 |year=2007 |pages=648–653 |doi=10.1093/ejo/cjm073 |pmid=17878186}}</ref><ref name="legan">{{cite journal |last1=Legan |first1=Harry L. |last2=Burstone |first2=Charles J. |title=Soft tissue cephalometric analysis for orthognathic surgery |journal=Journal of Oral Surgery |volume=38 |issue=10 |year=1980 |pages=744–751 |pmid=6932485}}</ref> A straighter run through those three points sits nearer 180°. Looksmaxxing reads a more convex profile (chin behind the midface) as a weak lower third, and a concave profile as a strong chin or a recessed midface.

Two conventions collide in forum talk. Some papers report the '''internal''' angle at subnasale (often ~165–175° in orthognathic Class I talk). Others report the '''supplement''' — how far the profile departs from a straight line (Legan and Burstone’s facial-convexity figure near 12° ± 4° in a Caucasian surgical sample).<ref name="legan" /> The same face can be “12° convex” and “168° G–Sn–Pog.” State which construction you mean.

Godt and colleagues compared several photographic convexity angles against skeletal Class from Wits appraisal. Variants through nasion or glabella to Sn/Pog separated Class II from Class III cleanly; Class I versus Class II was harder, and method error sat around a degree.<ref name="godt" /> A phone screenshot is not a cephalogram.

== Method ==
What moves the angle is bone and fat, not a filter.

* '''Chin''' — [[sliding genioplasty]] or an implant advances Pog′ and flattens a convex profile. See [[Riedel's line]].
* '''Midface''' — [[bimaxillary osteotomy]], [[MARPE]], or a [[paranasal implant]] changes Sn relative to the chin.
* '''Fat and posture''' — submental fat and a forward head fake convexity on camera. [[Body fat]] and [[chin tuck]] are the free levers.
* '''Ceph''' — a lateral film in natural head position is the clinical tool.<ref name="ceph">{{cite web |url=https://en.wikipedia.org/wiki/Cephalometric_analysis |title=Cephalometric analysis |website=Wikipedia |access-date=12 October 2026}}</ref>

== This wiki's view ==
Convexity is a useful profile word if you name the landmarks. It is not a PSL score. Do not treat a 165° screenshot as a surgical indication.

== See also ==
* [[Ricketts E-line]]
* [[Riedel's line]]
* [[Chin]]
* [[Pogonion]]
* [[Midface]]
* [[Orthognathic surgery]]

== References ==
{{Reflist}}

[[Category:Anatomy]]
[[Category:Face]]
[[Category:Glossary]]