Measurement · U1APOG
U1 to A-Pog (mm)
Loading the reference ceph.
Definition
The perpendicular distance from the upper incisal tip to the A–Pogonion line (the dental midline reference of Downs/Ricketts).
How
Draw the A–Pog line (denture line from A point to the chin); drop a perpendicular from U1T; read in mm, positive anterior (norm ≈ 2.7 mm).
Purpose
Places the upper incisor against the line connecting the two 'stable' anterior skeletal points — a profile-linked incisor position target used for finishing esthetics.
High
Above the norm reads as upper incisors protrusive relative to the A–Pog denture line.
Low
Below the norm reads as upper incisors retruded relative to A–Pog.
This is a reviewed tracing on one real cephalogram — the same ceph on every page in Learn — so U1 to A-Pog (mm) here is a real reading and not a diagram.