Measurement · L1APOGANG
L1 to A-Pog (angle)
Loading the reference ceph.
Definition
The angle between the lower incisor's long axis and the A–Pogonion line.
How
Draw A–Pog and the L1 long axis (L1A→L1T); measure the angle between them (norm ≈ 22°).
Purpose
The torque companion to the L1–APog mm value: together they say whether the lower incisor's position is bodily or tipped, which decides the mechanics (torque vs tipping) needed to reach the Ricketts target.
High
Above the norm reads as lower incisor crown tipped forward on the denture line.
Low
Below the norm reads as lower incisor upright/retroclined on the denture line.
This is a reviewed tracing on one real cephalogram — the same ceph on every page in Learn — so L1 to A-Pog (angle) here is a real reading and not a diagram.