Bronchial arteries

Bronchial arteries (Latin: arteriae bronchiales) are the main vessels that supply the bronchi and the lungs with oxygenated blood and nutrients. However, they are responsible for only 1% of the blood flow to the lungs overall. 

The anatomy of bronchial arteries is quite variable, but usually, two bronchial arteries supply the left lung, while one supplies the right lung.

Course

The bronchial arteries are located in the posterior mediastinum. They arise most commonly from the thoracic aorta (but may also arise from other vessels) at the T3 - T8 levels, most often from the T5 - T6 level. There are usually three main bronchial arteries, one on the right side and two on the left. Still, there are often additional bronchial arteries, which originate from the thoracic aorta and are usually smaller than the main ones.

The main bronchial arteries enter the lungs via the pulmonary hila and branch into smaller vessels - down to the level of the respiratory bronchioles.

Proximally, the left bronchial arteries travel to the left of the esophagus. The right bronchial artery may run to the right or the left of the esophagus.

Left bronchial arteries

There are usually two left bronchial arteries that typically arise directly from the descending thoracic aorta:

• superior left bronchial artery - originates from the thoracic aorta near the level of the aortic arch, lateral to the carina, and posterior to the left main bronchus;
• inferior left bronchial artery - arises from the thoracic aorta in a parallel manner to the superior left bronchial artery, but inferior to the left main bronchus.

Right bronchial artery

There is typically a single right bronchial artery. It usually originates from one of the following vessels: 

• the thoracic aorta at a common trunk with the right third intercostal artery,
• the superior bronchial on the left side, or 
• any of the right intercostal arteries, most commonly - the third right posterior.

Supply

The bronchial arteries provide arterial blood supply to the trachea, the bronchi, and the connective tissue of the lungs. They form anastomoses with branches of the pulmonary artery, supplying the visceral pleura on their way. Each bronchial artery also gives off a branch that supplies the middle third of the esophagus. Besides, the bronchial arteries may participate in supplying other structures within the mediastinum as well.