Fourth (4th) branchial arch artery (embryology)

The fourth branchial arch arteries are the fourth pair to form. As would be expected from their name, they are sited within the fourth pair of branchial arches.

In the mature heart, the fourth branchial arch artery contributes to different structures on the each side. On the left it forms a section of the arch of the aorta intermediate to the third arch derivatives - left common carotid artery and its immediately distal vessels - and the left subclavian artery. On the right it forms the proximal part of the right subclavian artery.