Azygous vein drains: (A) Into superior vena cava, (B) Anterior to costochondral junction, (C) Oesophagus, (D) Directly into right atrium
Answer is A. The azygous vein is formed by the confluence of the Lumbar azygous vein, Right ascending lumbar vein and right subcostal vein. It passes superiorly through the aoic apeure, posterior to the right diaphragmatic crus and anterior to the twelth veebral body. The azygos vein transpos deoxygenated blood from the posterior walls of the thorax and abdomen into the superior vena cava vein.