The neck and head are supplied by the common carotid arteries and the vertebral arteries. The common carotid arteries arise from the horns of the aortic sacs after some reorganization and then divide into the internal and external carotid arteries. The vertebral arteries join into the basilar artery at the base of the brain, which forms anastomoses with the internal carotid arteries. The internal carotid artery gives rise to the ophthalmic artery. Then it subdivides into the anterior cerebral artery, middle cerebral artery and a branch orientated posteriorly. This posterior branch finally becomes the posterior communicating artery and anastomoses with the basilar artery.
Arterial blood is supplied to the limbs through axial arteries, which arise from lateral branches of the 7th cervical (arm) / 5th lumbar (leg) intersegmental arteries. Ongoing development of the limbs gradually modifies the axial arteries.