subcostal vein

:  either of two veins:a:  one that arises on the right side of the anterior abdominal wall, follows a course along the lower margin of the twelfth rib, and joins in the formation of the azygos vein—called also right subcostal veinb:  one on the left side of the body that usually empties into the hemiazygos vein—called also left subcostal vein