Did Caravaggio recognize venous blood was flowing centrally?

Jugular venous distention, which implies the presence of a superior vena cava syndrome, has been described in Hellenistic sculpture and early modern painting. This is unusual and remarkable considering this was done before the discovery of the true nature of the human circulatory system (1628) or the discovery of superior vena cava syndrome (1757). One has to wonder whether these artists only expressed what they saw or were aware of what they were depicting in their work. Caravaggio is the only artist who demonstrated this condition in his paintings and about whom we know enough to comment. This contribution discusses the influence of Michelangelo, who had anatomic training, on Caravaggio's work. It also discusses Caravaggio's knowledge and his use of messages in his work, as well as what was known about human circulation during his lifetime. This discussion is intended to help us appreciate what Caravaggio could have known and been trying to convey through his art, and in doing so, aid us in the practice of medicine by improving our awareness of life's mysteries.