Bronchial artery

The bronchial arteries are responsible for only 1% of the lung blood flow but they are the major high-pressure oxygenated blood supplier to the supporting structures of the lung parenchyma including pulmonary arteries. The classic pattern described below of two bronchial arteries on the left and one on the right is found in ~70% of patients.

Gross anatomy

The bronchial arteries typically arise from the thoracic aorta at the T3-T8 levels with ~70% (range 64-80%) arising from the T5-T6 level ⁵. They are small calibre arteries, with a diameter of 1.5 mm at the origin, tapering down to approximately 0.5 mm at the pulmonary hila level ⁶. Their small branches then form a network of arteries running along the external bronchial surface, giving also penetrating branches to supply the submucosal arterial network. 

Left bronchial arteries

There are usually two bronchial arteries on the left that arise directly from the anterior surface of the thoracic aorta:

• superior left bronchial artery: arises from the anteromedial surface of the aortic arch, lateral to the carina and posterior to the left main bronchus
• inferior left bronchial artery: also arises from the aorta and is parallel to the superior artery, but inferior to the left main bronchus

Right bronchial artery

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

Supply

• trachea and bronchi
• lymph nodes
• visceral pleura
• pericardium
• oesophagus (middle-third)
• posterior mediastinum
• vagus nerve
• vaso vasorum of the aorta, pulmonary trunk and pulmonary vein

Variant anatomy

Origin

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:

• aortic arch
• internal thoracic artery
• thyrocervical trunk
• subclavian artery
• coronary arteries

Branching patterns

• 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

Related pathology

• haemoptysis
• bronchial artery enlargement
• bronchial arterial aneurysm
• broncho-arterial ratio