Accessory Hemiazygos Vein Apr 2026

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

: The vein descends along the left side of the 4th to 8th thoracic vertebrae. At approximately the level of the 7th or 8th thoracic vertebra (T7-T8) , it crosses the midline to the right, passing posterior to the aorta and esophagus, to drain into the azygos vein. Tributaries : Left 4th to 8th posterior intercostal veins. Left bronchial veins (variable). Some esophageal and mediastinal veins. Anatomical Variants accessory hemiazygos vein

The azygos system is notoriously highly variable . Common variants include: : It may join the hemiazygos vein to

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