abnormal aorta morphology aorta hypoplasia 2010-10-04T09:09:24Z MP:0010541 MPheno.ontology aortic hypoplasia csmith underdevelopment or reduced size of the main trunk of the systemic arterial system that originates from the base of the left ventricle of the heart and extends to the abdomen at the point where it branches into the common iliac arteries, usually due to reduced cell number