: It may join the hemiazygos vein to form a common trunk before entering the azygos vein.
: 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 accessory hemiazygos vein
: In rare cases (1–2%), it may drain directly into the left brachiocephalic vein . : It may join the hemiazygos vein to