Subcostal arteries
The subcostal arteries, so named because they lie below the last ribs, constitute the lowest pair of branches derived from the thoracic aorta, and are in series with the intercostal arteries.
Anatomy
Course and relations
Each intercostal artery is accompanied by the corresponding subcostal vein and nerve.' Each passes along the lower border of the 12th rib.'Before entering the anterior abdominal wall, each runs laterally upon the anterior surface of the lumbar fascia posterior to the ipsilateral kidney. It then pierces the posterior aponeurosis of the transversus abdominis, thus entering the anterior abdominal wall to course in between the abdominal internal oblique muscle and transverse abdominal muscle.''''''