Gonion
Pronunciation: GOH-nee-on
The most posteroinferior point of the mandibular angle, used as a cephalometric landmark in constructing the mandibular plane and measuring the gonial angle.
Full Definition
Gonion (abbreviated Go) is located at the intersection of the ramus and the lower border of the mandible and is typically identified geometrically as the point where a bisector of the angle formed by the posterior ramus line and the mandibular lower border meets the mandibular contour. It is a key landmark in numerous cephalometric analyses and growth studies. Editors must capitalise 'Gonion' as a proper landmark name and distinguish it from the 'gonial angle,' which is the angular measure taken at that region. Precise description of how Gonion was identified (hard-tissue vs. constructed) should be confirmed in methods sections. Errors in Gonion identification propagate into mandibular plane and ramus measurements.
Usage
Usage note: Capitalise consistently as a proper cephalometric landmark; distinguish 'Gonion' (the point) from 'gonial angle' (the angular measurement at that region).
In Context
- "The mandibular plane was constructed by connecting Gonion to Menton on each lateral cephalogram." — Cephalometric methods section
- "Gonion was identified as a constructed point using the bisector method described by Jacobson." — Landmark identification protocol