The aortic arch arteries are bilaterally paired arteries that originate at the aortic sac and develop from endothelial strands in the pharyngeal arches. These arteries ventrally connect with the already paired dorsal aortas located dorsal to the foregut. During early development, the aortic arch arteries carry all of the cardiac output. Interaction of neural crest cells with the aortic arch arteries is not necessary for formation of these arteries; however, cardiac neural crest cells do play an important role in re-patterning of these symmetrical arteries into the asymmetric great arteries. In mouse and human, aortic arch 3 form the common carotids. The right fourth aortic arch artery becomes the base of the subclavian artery and the left becomes the arch of the aorta. The left sixth aortic arch artery forms the ductus arteriosus and its right pair atrophies.