Development of the Arteries and the Aortic Arch

Primitive system

The pharyngeal arches grow out of the mesenchyme in the region of the head and neck, each which contains a cranial nerve and artery. Between day 26 and 29, vasculogenesis and angiogenesis result in the formation of six pairs of aortic arches from the aortic sac. These arteries serve to connect the developing heart with the dorsal aorta. Endothelial precursor cells from the surrounding mesoderm and neural crest cells are crucial for proper development of the aortic arches.

Aortic arches

The aortic arches are a series of six arches that develop consecutively to connect the aortic sac with the paired dorsal aorta. Cardiac neural crest cells migrate through aortic arches 3, 4, and 6 during weeks 3-4 of human development. This process is crucial for normal cardiac development, including the arches themselves.

The first pair forms between day 22 and 24; both arches regress as the second arch forms on day 26 (later atrophying as well). The first three arches aim to supply the cranial and cervical regions and form the internal carotid artery among others. The external carotid artery arises later as an independent vessel. The fourth aortic arch develops unsymmetrically. The left fourth arch forms the proximal part of the adult aortic arch, whereas the right one evolves into the right subclavian artery. The last two arches, 5 and 6, do not appear in large arch shape. The ductus arteriosus is formed by a left dorsal branch from the dorsal aorta, and connects the aortic sac with the pulmonary arteries as a shunt. The left subclavian artery originates from the left seventh intersegmental artery. The aortic valve originates from conotuncal ridge tissue and forms three triangular valve leaflets.

Synopsis origin of major blood vessels