Bronchoesophageal veins

The bronchoesophageal veins are variable small systemic veins that drain venous blood from the bronchi and the thoracic portion of the esophagus in the right azygos vein.

Their denomination may be confusing between sources:

• The bronchoesophageal veins (termed as bronchial tributaries of azygos vein in humans) are all the venous branches draining the bronchi and emptying in the right azygos vein.

• The bronchoesophageal vein, is the largest of these venous tributaries and terminate in the azygos vein, usually at the level of the seventh thoracic vertebra and is satellite of the comparable artery (bronchoesophageal artery). This bronchoesophageal vein is not always present. Its roots often drain instead into the concavity of the mediastinal segment of the right azygos vein, or even into a neighboring vein. It may be unpaired (Equidae), bilateral (Carnivores, Rabbit), or replaced (Ruminants, Pig, Human) by small bronchial (Vv. bronchales) and esophageal veins (Vv. oesophageae). It may also empty into the cranial vena cava (Cat), the costocervical vein, or a dorsal intercostal vein (Dog, on the left).

• The esophageal veins (esophageal tributaries of azygos vein in human anatomy) are delicate mediastinal tributaries, terminating in the azygos vein caudal to the termination of the bronchoesophageal vein. There are usually two of these, 1 to 3 cm apart, that cross the right face of the aorta to empty into the ventral surface of the azygos vein.