<prompt> Intercostal veins drain into:Left subclavian veinInternal jugular veinAzygous veinInferior vena cava  <response>: Ans. C Azygous veinRefi BDC 6th ed. vol. 1221 -222; Keith L. Moore 5th ed. 105POSTERIOR INTERCOSTAL VEINS One in each of the 11 spaces On the right: 1st drains into Rt. innominate vein A 2nd, 3rd sometimes the 4th unite to form Rt. Superior Intercostal vein B which drains into azygos vein. From 5th to 11th subcostal veins drain into azygos vein C. On the left: 1st drains into Lt. innominate vein A 2nd, 3rd sometimes the 4th join to form Lt. Superior intercostal vein which drains into Lt innominate vein vein B 5th, 6th, 7th 8th form superior hemiazygos vein to azygos vein D 9th, 10th, 11th subcostal form inferior hemiazygos veins drain to azygos vein E. 