Unit 3 of 7
The mandible
The lower jaw, from the angle to the chin — and the number that names the class.
The card
Five points, and between them they settle the two questions a skeletal diagnosis asks: how far forward is the chin, and how steeply does the jaw grow down and back. ANB — the difference between the maxilla you just learned and the mandible you are about to — is the number that names the class.
- B point is the mandible's answer to A point: the deepest concavity above the chin, and the spread there runs vertically.
- Pogonion, Gnathion and Menton walk round the chin — most anterior, most anteroinferior, most inferior.
- Gonion is the corner of the jaw, found by bisecting the angle between the ramus and the lower border.
- ANB is SNA minus SNB, and two degrees of it is a whole skeletal class.
What you will place