The subcostal arteries are bilateral small arteries that arise of the distal descending aorta which courses laterally beneath the 12th rib. They are the last
The subcostal arteries are analogous to the posterior intercostal arteries, instead in the subcostal space rather than an intercostal space. They pass in front of the T12 vertebrae and behind the sympathetic trunk, pleura, and diaphragm. On the right, the subcostal artery also runs posterior to the thoracic duct and azygos vein, whereas the left runs posterior to the accessory hemiazygos vein.
The subcostal artery divides into the anterior and posterior rami like the posterior intercostal artery.
Along with the lower posterior intercostal arteries, the subcostal arteries supply the muscles and skin beneath the 12th rib of the anterolateral abdominal wall.