Accessory Hemiazygos Vein — Fresh

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

: In rare cases (1–2%), it may drain directly into the left brachiocephalic vein . accessory hemiazygos vein

The accessory hemiazygos vein is an unpaired vessel that typically resides on the left side of the vertebral column, parallel to the descending thoracic aorta. The (also known as the superior hemiazygos vein