 Aorticopulmonary septum

The aorticopulmonary septum (also called the spiral septum, or aortic septum in older texts) is developmentally formed from neural crest, specifically the cardiac
neural crest, and actively separates the aorta and pulmonary arteries and fuses with the interventricular septum within the heart during heart development.In the developing heart, the truncus arteriosus and bulbus cordis are divided by the aortic septum.