Figure 1.

Schematic drawing of the development of the aortic arch and its branches. 1, first aortic arch; 2, second aortic arch; 3, third aortic arch; 4, fourth aortic arch; 5, fifth aortic arch; 6, sixth aortic arch; aa, aortic arch; va, ventral aorta; da, dorsal aorta; cc, common carotid artery; ic, internal carotid artery; ec, external carotid artery; rs, right subclavian artery; av, vertebral artery; pt, pulmonary trunk; rp, right pulmonary artery; lp, left pulmonary artery; db, ductus arteriosus Botalli.