The bronchial veins are small vessels that return blood from the larger bronchi and structures at the roots of the lungs.

It also drains, although with less significance, to the hemiazygos vein, posterior intercostal vein and bronchial veins.

Other tributaries include the bronchial veins, pericardial veins, and posterior right intercostal veins.

In some rare variations for example, it also drains thoracic veins, bronchial veins and even gonadal veins.

Note that much of the blood supplied by the bronchial arteries is returned via the pulmonary veins rather than the bronchial veins.

The bronchial veins are counterparts to the bronchial arteries; however they only carry 13% of the blood flow of the bronchial arteries.

This is due to blood from the bronchial veins and some veins draining the left ventricle of the human heart draining into blood in the systemic circulation without undergoing gas exchange.

These include the pulmonary artery, superiormost on the left lung, the superior and inferior pulmonary veins, lymphatic vessels and the bronchus, with bronchial veins and bronchial arteries surrounding it.

It receives the posterior intercostal veins from the 4th, 5th, 6th, and 7th intercostal spaces between the left superior intercostal vein and highest tributary of the hemiazygos vein; the left bronchial vein sometimes opens into it.