There is a correspondence between the number of intercostal vein and the number of intercostal arteries. Two anterior intercostal veins and 1 posterior intercostal vein are included in every intercostal space. The branches of the arteries are correspondent to their tributaries.
Anterior Intercostal Veins
They’re present only in the upper 9 spaces and every space includes 2 veins and accompanies the anterior intercostal arteries.
They conclude in the upper 6 spaces, they stop in the internal thoracic vein and in seventh, eighth, and ninth spaces, they stop in the musculophrenic vein.
Posterior Intercostal Veins
They’re found in all the spaces where every space includes only 1 posterior intercostal vein and every vein accompanies the posterior intercostal artery.
The manner of drainage (conclusion) of posterior intercostal veins differs on the left and right sides.
Style of conclusion of left and right posterior intercostal veins.