Abnormally flat (obtuse) angle of the mandible. The angle of the mandibular, located at the junction between the body and the ramus of the mandible, is normally close to being a right angle. This terms describes an abnormal increase of this angle such that the mandible appears flatter than normal. The phenotype is HP_0005446 (Obtuse angle of mandible). Also known as: High mandibular plane angle, Steep mandibular plane angle.