Venous drainage of the thoracic esophagus toward the pulmonary vein.

Venous drainage of the thoracic esophagus toward the pulmonary vein (PV) was investigated in 52 human specimens in which the veins around the esophagus were clearly observed owing to venous blood retention after injection of 10 L of formol solution into the femoral artery. Below the level of the tracheal bifurcation, 43 cases (right, 21; left, 22) of venous drainage toward the PV were observed in 29 of the 52 specimens examined (55.8%). The direct drainage to the PV was observed mainly on the left side (19 of the 22 cases). In contrast, drainage via the bronchial vein toward the PV existed mainly on the right side (18 of the 21 cases). These drainage routes merged into the tributaries of the inferior PV, such as the inferior or superior basal vein. The draining veins often communicated with the azygos vein system on the right side (10 of the 21 cases). The veins passed through the pulmonary ligament, and also often along the vagus nerve or the bronchial artery. No venous valves were found during the course of direct drainage from the esophagus to the PV. Venous drainage toward the PV was considered to be one of the main drainage routes from the thoracic esophagus.