It continues ascending on the left side of the vertebral column, and around the level of the ninth thoracic vertebra, it passes rightward across the column, behind the aorta, esophagus, and thoracic duct, to end in the azygos vein.

[4] The dilated hemiazygos system displayed by chest or abdominal X-ray films can be misdiagnosed as a mediastinal or retroperitoneal neoplasm, lymphadenopathy or aortic dissection (2, 5–7, 10).

In the case of hemiazygos continuation of the IVC, the hepatic veins can drain directly into the right atrium (3, 10).

An incidental finding of this condition during venous cannulation for cardiopulmonary bypass complicates the procedure, since no solid IVC trunk for placing the cannula is present.

This article incorporates text in the public domain from page 667 of the 20th edition of Gray's Anatomy (1918)