has part has part characteristic of part of has modifier Abnormal mandible morphology Broad jaw The lower jaw 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. When a broad jaw is accompanied by a broad upper face the term Square face is used. abnormal increased width mandible