Bronchial arteries

The bronchial arteries (Latin: arteriae bronchiales) are the main vessels that supply the bronchi and lungs with oxygenated blood and nutrients. However, they are responsible for only 1% of the blood flow to the lungs overall. The anatomy of the bronchial arteries is quite variable, but usually, two bronchial arteries supply the left bronchi and lung, while one supplies the bronchi and lung on the right side.

Course of bronchial arteries

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 vertebral levels, most often at 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 along the left side of the esophagus. The right bronchial artery may run on the right or the left side of the esophagus.

Left bronchial arteries

As mentioned before, there are usually two bronchial arteries on the left side. The left bronchial arteries typically arise directly from the descending thoracic aorta, and they are known as:

  • Superior left bronchial artery - originates from the thoracic aorta near the level of the aortic arch, lateral to the carina of the trachea, 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:

  • Thoracic aorta - typically starting as a common trunk with the right 3rd intercostal artery;
  • Superior bronchial artery on the left side;
  • Any of the right intercostal arteries, most commonly - the 3rd right posterior intercostal artery.

Supply

The bronchial arteries provide arterial blood supply to the trachea, 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. Also, the bronchial arteries may participate in supplying other structures within the mediastinum as well.