Accessory Hemiazygos Vein Apr 2026

The azygos system is notoriously highly variable . Common variants include:

: It is formed by the confluence of the 4th through 8th left posterior intercostal veins . accessory hemiazygos vein

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 The azygos system is notoriously highly variable

: If the vein is underdeveloped or absent, the left superior intercostal vein may extend further down to drain those levels. Clinical Significance Accessory Hemiazygos Vein | Complete Anatomy - Elsevier Located in the upper left posterior mediastinum, it

: It may join the hemiazygos vein to form a common trunk before entering the azygos vein.