Measurement · MBODY
Mandibular body length (Go–Gn)
Loading the reference ceph.
Definition
The length of the mandibular corpus from Gonion to Gnathion.
How
Measure Go→Gn in mm. Jarabak expected body length ≈ anterior cranial base length (N–S) at maturity (about 1:1).
Purpose
Sizes the tooth-bearing body of the mandible. Compared to N–S it flags true mandibular under/overdevelopment; it also bounds how much arch length the lower jaw can ultimately hold.
High
Above the norm reads as a long mandibular body (Class III contribution).
Low
Below the norm reads as a short mandibular body (true mandibular deficiency, Class II contribution).
This is a reviewed tracing on one real cephalogram — the same ceph on every page in Learn — so Mandibular body length (Go–Gn) here is a real reading and not a diagram.