Origin of great vessels and ductus arteriosus

Shown is the morphologic derivation of proximal pulmonary and aortic vessels at birth. The main pulmonary artery (MPA) comes from the fused ventral VI^th arterial arch (FV-VI), while the right and left pulmonary arteries (RPA and LPA) come from the right (RV-VI) and left ventral VI^th arterial arches (LV-VI). The ascending aorta (AAo) and right brachiocephalic artery (RBCA) are derived from the right ventral IV^th arterial arch (RV-IV), while the aortic arch (Ao arch) comes from the left ventral IV^th arterial arch (LV-IV). The ductus arteriosus (DA) is derived from the left dorsal VI^th arch (LD-VI).