has part has part characteristic of part of inheres in part of has modifier Abnormal mandible morphology Narrow jaw 2014-05-25T02:37:13Z Narrow lower face The width of the 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. Bigonial distance (lower facial width) more than 2 standard deviations below the mean (objective); or an apparently decreased width of the lower jaw (mandible) when viewed from the front (subjective). Narrow mandible Narrow jaw UMLS:C4021066 Thin lower face HP:0012801 UMLS:C4280310 Narrow lower jaw Thin lower jaw abnormal decreased width mandible