abnormal conotruncal ridge morphology conotruncal ridge hyperplasia 2010-10-05T02:26:55Z MP:0010588 MPheno.ontology aortico-pulmonary spiral ridge hyperplasia bulbar ridge hyperplasia conotruncal cushion hyperplasia csmith endocardial ridge hyperplasia outflow tract cushion hyperplasia overdevelopment or increased size of the pair of spiral mesenchymal swellings in the primordial ventricular outflow tract, that eventually fuse to form the conotruncal septum, dividing the subvalvular outflow tract and contributing to the membranous interventricular septum