<prompt> Thoracic duct opens into:Subclan veinInternal jugular veinRight brachiocephalic veinLeft brachiocephalic vein  <response>: Thoracic duct is continuation of cysterna chyli. It passes through aoic hiatus beginning at lower border of T12 . At T5 it crosses to left side andopens into the left venous jugulo-subclan angle - junction of the left internal jugular and subclan vein, at the beginning of left brachio-cephalic vein. 