The left supraclavicular nodes are the classical Virchow's node because they receive lymphatic drainage of most of the body (from the thoracic duct) and enters the venous circulation via the left subclavian vein.
The left supraclavicular nodes are Virchow's node because they collect lymphatic fluid from most of the body (via the thoracic duct) and then enter the venous system through the left subclavian vein.