Aortic arches represent intermediate structures which resolve into the adult configuration within the 6-8 week of development. These arise to supply the pharyngeal arches with blood during the development of structures in the head and neck.
Moore and Persaud present an excellent series of illustrations which cover the development, changes and fates of the aortic arches. Please refer to pages 386-387 in the 6th Edition of The Developing Human Clinically Oriented Embryology.
A patent ductus arteriosus is an anomaly of the aortic arches.