The place of origin of the bronchial arteries is subject to considerable variation. The left bronchial arteries, usually two, arise from the ventral surface of the thoracic aorta. In 265 individuals a left bronchial arises in common with a right bronchial. The artery of the right side has been found to arise singly from the aorta, from the internal thoracic, or from the inferior thyroid. In some cases the bronchials arise from the inferior surface of the arch instead of from the descending thoracic aorta.
Instances also occur of two distinct bronchial arteries for each lung.
The bronchial artery of the ventral surface of the esophagus usually passed anterior to the bifurcation of the trachea, ultimately reaching the inferior border of the right main bronchus. Anastomoses between these esophageal vessels and the ascending branch of esophageal arteries of thoracic aortic origin occurred in many instances. Esophageal arteries of this latter origin rarely formed a gross anastomosis with any other esophageal vessel. In fact, the portion of the thoracic esophagus appeared to be less well supplied by esophageal vessels than any other portion of the tube. From Intercostal Arteries.