The bronchial arteries supply nutrition to the parenchymal tissues of the lung between the carina and respiratory bronchioles. Along this route, they ramify with the bronchial tree in relation to the posterior aspect of the respective bronchi.
The origin of the main bronchial arteries depends on the side:
- usually only one artery
- usually arises from the third right posterior intercostal artery, a branch of the aorta
- rarely, may arise from thoracic aorta via the superior left bronchial artery
- usually two arteries
- arise directly from aorta
- superior left bronchial artery arises from anteromedial surface of the aortic arch just lateral to the carina and posterior to the left main bronchus
- inferior left bronchial artery also arises from aorta parallel to its superior counterpart, but at a point that is inferior to the left main bronchus
Eventually, the bronchial arteries form capillaries which are continuous with either the pulmonary or bronchial veins.
Inflammation and thrombosis of the bronchial arteries may lead to gradual reactive enlargement of the bronchial tree. This may be associated with massive haemoptysis.