Objective: Bigonial distance (lower facial width) more than 2 SD below the mean
Subjective: Apparently decreased width of the lower jaw (mandible) when viewed from the front
This dimension is measured from the right gonion to the left gonion using spreading calipers. The gonion is the point at the angle of the bony mandible where the ramus changes direction to become the body of the mandible. It faces inferiorly and medially and is best found by placing a finger over the outward facing angle and rolling the finger downwards and inwards [Farkas, ].