Engraving of the venous system from De Humani Corporis Fabrica (On the Structure of the Human Body) by Andreas Vesalius, first published in 1543. It was captioned insA delineation of the entire vena cava freed from all its partsins. Following traditional views, the venous system is depicted as a single continuous vessel. It is not clear who did many of the drawings; some scholars believe Titian may have been involved and certainly Jan van Kalkar and Domenico Campagnola contributed.