Glossary
What is gonial angle?
Last updated: May 22, 2026
The gonial angle is the angle formed at the back corner of the jaw where the horizontal mandibular body meets the vertical mandibular ramus. A sharper (more acute) gonial angle produces a more defined jawline in profile view. A wider (more obtuse) angle softens the jaw line. The angle is one of several cephalometric measurements used in orthodontics and facial aesthetic planning.
How gonial angle is measured
Measured in degrees from a profile (lateral) photograph or radiograph. The gonion (the angle vertex) is identified and the angle between the mandibular body and ramus is measured.
Why gonial angle matters
Gonial angle is a primary determinant of jaw definition visible in profile. Square jaws with sharper gonial angles read more masculine; wider gonial angles read softer and more feminine. Gonial angle can be modified by mandibular angle reduction surgery (decreases jaw width) or jaw implant augmentation (increases definition).
Normal range
Typical adult male: 110 to 125 degrees. Typical adult female: 115 to 130 degrees. Variation by ethnicity exists.
Source: Standard cephalometric references
How Facet uses gonial angle
Facet does not currently measure gonial angle because it requires a profile view photograph. Gonial angle is on the V3 roadmap as part of the profile-CV pipeline.
Frequently asked
Is gonial angle the same as 'jawline definition'?+
Closely related but not identical. Gonial angle is one of several factors (along with masseter muscle development, body fat, skin tightness, and overall mandibular projection) that contribute to perceived jaw definition.
Can gonial angle be changed?+
Yes. Mandibular angle reduction (osteotomy) decreases the angle width and is a major surgical procedure with significant recovery. Mandibular angle augmentation via implants is less invasive but still surgical. Both are irreversible and require qualified maxillofacial surgeon consultation.