Assertion: primum defect | /r/CapableOf | form two av valves
Facets:
Source sentences:
text: A primum defect is part of an atrioventricular (AV) septal defect with a common AV junction and is roofed superiorly by the inferior border of the oval fossa and inferiorly by the superior and inferior bridging leaflets, forming two AV valves.