The azygos vein (Fig. 46.1) is usually found on the right side of the posterior mediastinum, ascending from the diaphragm and traveling along the eight inferior-most thoracic vertebral bodies to empty into the superior vena cava (SVC). The following account describes the azygos vein as commonly seen, but it is important to note that the origin, tributaries, anastomoses, and termination of this vein are all highly variable (Standring 2021).