Bronchial branches of internal thoracic artery

Bronchial branches of the internal thoracic artery are ectopic (variant) bronchial arteries that arise from the internal thoracic artery (ITA, also known as the internal mammary artery) rather than from their typical origin at the descending thoracic aorta. These represent a rare anatomical variant of the bronchial arterial supply to the lungs.

The bronchial arteries normally originate from the descending thoracic aorta between the T5 and T6 vertebral levels, either as independent branches, from a common trunk, or from an intercostobronchial trunk. These arteries account for approximately 1% of cardiac output and provide the systemic blood supply to the bronchial tree, bronchial walls, and surrounding pulmonary connective tissue.

The internal thoracic artery as an ectopic origin

In a large CT angiography study of 315 bronchial arteries, the vast majority arose from the thoracic aorta (74.60%) or aortic arch (23.49%), while only 1.90% originated from ectopic sources, which included the subclavian artery, thyrocervical trunk, and the internal thoracic artery. Specifically, a left bronchial artery arising from the left ITA was documented as one such rare variant. The ITA is recognized as one of the possible ectopic origins of bronchial arteries alongside the subclavian artery and thyrocervical trunk.