The intercostal veins are a group of veins which drain the area between the ribs ("costae"), called the intercostal space. They can be divided as follows: Anterior intercostal veins Posterior intercostal veins Posterior intercost vein that drain into the Supreme intercostal vein - 1st intercostal space Posterior intercost veins that drain into the Superior intercostal vein - 2nd, 3rd, and 4th intercostal spaces. The superior intercostal vein then drains into the Azygous vein. Posterior intercost veins that drain directly into the Azygous vein - in spaces 5-11. Subcostal vein -- below bottom (12th) rib and also drains into the Azygous vein. See also Intercostal nerves External links http://www.instantanatomy.net/thorax/vessels/vinsuperiormediastinum.html Veins of the torso