abnormal zygomatic arch morphology zygomatic arch hypoplasia 2017-11-10T11:48:32Z MPheno.ontology MP:0030377 hypoplastic malar arch decrease in the number of normal cells in normal arrangement in the zygomatic arch, typically resulting in decreased size hypoplastic zygomatic arch hypoplastic zygoma facial bone hypoplasia zygomatic arch hypoplasia