Chest and neck arteries (white), coloured magnetic resonance angiography (MRA) scan. The heart (lower centre) pumps blood for oxygenation into branching arteries in the two lungs (green) on either side. Oxygenated blood is pumped into the main artery, the aorta. The aortic arch (centre) loops over and behind the heart, descending to the lower body. Arteries branching from the top of the aortic arch supply the upper body: the right subclavian artery for the right arm (upper left), the left and right common carotid arteries for the neck (top centre, also external and internal branches) and the left subclavian artery for the left arm (upper right).