This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
Left first Posterior Intercostal vein drains into: 
Select and explain. 
A. Brachiocephalic vein, B. Azygos vein, C. Hemiazygos vein, D. Accessory Hemiazygos vein
A: Brachiocephalic vein
Answer: A: Brachiocephalic vein 
Explanation: Ans. A. Brachiocephalic veinThe left and right brachiocephalic veins (or innominate veins) in the upper chest are formed by the union of each corresponding internal jugular vein and subclavian vein. This is at the level of the sternoclavicular joint. The left brachiocephalic vein is usually longer than the right. Left first Posterior Intercostal vein drains into left Brachiocephalic vein.