The azygos system is notoriously highly variable . Common variants include:
The (also known as the superior hemiazygos vein ) is a major component of the Azygos venous system . Located in the upper left posterior mediastinum, it serves as the left-sided counterpart to the superior portion of the azygos vein, primarily draining the mid-to-upper thoracic wall. Anatomical Overview accessory hemiazygos vein
: It is formed by the confluence of the 4th through 8th left posterior intercostal veins . The azygos system is notoriously highly variable