Aoic arch development involves the sequential development and then involution of six arch pairs, which arise from paired dorsal aoae that fuse distally. The fifth aoic arch is rudimentary. Double aoic arch is the result of persistence and continued patency of the segment of the right dorsal aoa between the origin of the right seventh intersegmental aery and its junction with the left dorsal aoa. Ref: Keller B.B., Markwald R.R., Hoying J.B. (2011). Chapter 9. Molecular Development of the Hea. In V. Fuster, R.A. Walsh, R.A. Harrington (Eds), Hurst's The Hea, 13e.