Which aortic arch forms the Aortic Arch during embryologic development of the heart?

The fourth left aortic arch is the structure responsible for forming the aortic arch during embryonic development. During the development of the cardiovascular system, the aortic arches are a series of structures that arise from the embryonic pharyngeal arches and play a crucial role in the formation of the mature great vessels.

Specifically, the fourth aortic arch differentiates into the aortic arch itself, which serves as a critical conduit for blood flow exiting the heart to the rest of the body. This arch is responsible for connecting the ascending aorta to the descending aorta and gives rise to the major arteries supplying the head, neck, and upper limbs, notably the left common carotid artery and the left subclavian artery.

In contrast, other aortic arches mentioned, such as the first, second, and third, do not contribute to the aortic arch in the mature heart. The first and second arches are involved in developing other structures but do not persist as major vessels in the adult. The third arch develops into the common carotid arteries and the proximal internal carotid arteries, not forming the main aortic arch. Hence, the fourth left aortic arch's pivotal role in forming the aortic arch is essential in understanding its significance in