Right superior intercostal vein drains into
The right superior intercostal vein drains the 2nd, 3rd, and 4th posterior intercostal veins on the right side of the body. It flows into the azygos vein. The left superior intercostal veins drains the 2nd and 3rd posterior intercostal veins on the left side of the body. It drains into the left brachiocephalic vein B D CHOURASIAS HUMAN ANATOMY UPPER LIMB THORAX VOLUME, 1 SIXTH EDITION, page no,221
Brachiocephalic vein
Azygos vein
Inferior venacava
Hemizygos vein
Thorax