Bronchial artery

Last revised by Yuranga Weerakkody on 7 Mar 2023

The bronchial arteries are the major supply of high-pressure oxygenated blood to the supporting structures of the lung, including the pulmonary arteries, but contribute only 1% of total lung blood flow. Blood in the bronchial circulation does not take part in gas exchange unless there is pathology reducing pulmonary arterial blood supply 10,11. Two left and one right main bronchial arteries are found in ~70% of patients. 

  • location: posterior mediastinum, in close association with aorta and bronchi

  • origin and termination: thoracic aorta (left); common intercostobronchial trunk (right); terminates at capillary plexi of respiratory bronchioles

  • branches and supply: variable

  • relations: frequently 

The bronchial arteries arise from their parent vessels at the T3-T8 levels, most commonly between T5-T6 level (~70%; range 64-80%) where it is termed an orthotopic origin 5. There are most commonly 3 main bronchial arteries, one right and two left. In addition, there are often additional smaller bronchial arteries arising from the descending thoracic aorta 7.

They are small caliber arteries, with a diameter of 1.5 mm at the origin, tapering down to approximately 0.5 mm at the pulmonary hila level 6

The main bronchial arteries course into the pulmonary hila, branching down to the level of the respiratory bronchioles 7. Proximally, the left bronchial artery passes to the left of the esophagus, while the right bronchial artery may pass to the right or left of the esophagus 8. Their small branches form a network of arteries running along the external bronchial surface, with penetrating branches to supply the submucosal arterial network and sometimes a subpleural pulmonary capillary plexus 7.

There are usually two left bronchial arteries that arise directly from the anteromedial thoracic aorta 8:

  • superior left bronchial artery: arises from the 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 aorta parallel to the superior artery, but inferior to the left main bronchus

The right bronchial artery has a common origin with a posterior intercostal artery called the intercostobronchial trunk (ICBT) and arises from the right anteromedial aspect of the thoracic aorta 8.

Bronchial artery anatomy is usually classified by the to Cauldwell Classification

Ectopic origin is present in ~20% (range 8.3-35%) of patients and is defined when they arise from the aorta outside of the level from superior endplate of T5 to inferior endplate of T6 1,5.

The bronchial arteries may arise from a wide range of arteries including 1,5:

Although most commonly arising from the anteromedial aspect of the descending aorta (superomedial aspect aortic arch), the origin may also be located at 8:

  • anterolateral aorta

  • posteromedial aorta

  • posterolateral aorta (rare)

  • common bronchial artery trunk (i.e. for both left and right bronchial arteries)

  • single bronchial artery bilaterally (i.e. one left and one right)

  • single bronchial artery on the left and two bronchial arteries on the right (one ICBT)

  • left bronchial artery less commonly has its origin from an ICBT

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