The left 4th arch artery becomes the arch of the aorta. The right 4th arch artery becomes the proximal subclavian. Pouch is the ultimobranchial body whose fate is unknown. E. Fifth Arch 1. Cartilage bar forms the cricoid, arytenoid, and corniculate.
Nerve is the recurrent laryngeal.
On the right, the artery degenerates and the nerve will loop around the subclavian. On the left, will loop around the aorta and ductus arteriosus. Left 5th arch artery becomes the pulmonary artery and ductus arteriosus. The right 5th arch artery becomes the pulmonary with degeneration of the rest of this arch vessel. Always lateral to the facial nerve.