abnormal maxilla morphology abnormal digestive organ placement retrognathia ectopic bone maxillary retrognathia 2017-10-11T13:28:53Z MP:0030274 abnormal posterior-shifted positioning of the upper jaw (maxilla) relative to the facial skeleton and soft tissues receding maxilla maxillary retroposition maxillary retrognathism retrognathia of upper jaw receding upper jaw MPheno.ontology