Description
The posterior intercostal veins are paired veins which drain each side of the posterior thoracic cavity. There are eleven pairs of posterior intercostal veins, which have a variable drainage pattern.
The supreme intercostal vein drains into its respective brachiocephalic vein. The second and third posterior intercostal veins both drain into their respective left and right superior intercostal veins. The right superior intercostal vein drains into the azygos vein, while the left superior intercostal vein drains into the left brachiocephalic vein.
The fourth to eleventh posterior intercostal veins on the right side drain into the azygos vein, while the fourth to eleventh posterior intercostal veins on the left side drain into the hemiazygos or accessory hemiazygos veins. This pattern is subject to variation.
Related parts of the anatomy
