The basic functioning of the circulatory system (Lat. circu + lat + ory, lit. “having to do with the act of carrying around”) was not fully understood until the 17th century, although Galen had come close a millennium and a half earlier. A general ignorance about the functioning of this system is partly evident in the system of names used: “vein” comes from the Latin and aptly describes the tunnel-like passages through which blood courses, but “artery” was thought to come from the Greek word for “.” The term was used to describe both arteries and the windpipe, and since post-mortem examinations found the arteries to be empty, it was speculated that they were passages for air and not blood (“artery” actually derives from the Greek verb meaning “to lift”).

Many names for arteries and veins were chosen based on location. The vein is found near the throat, the artery is found near the armpit, and the vein is found at the back of the knee. Based on what you have studied so far, you could also locate the cubital, brachial, femoral, and renal vessels respectively near the , , , and . It is also worth noting that the peroneal veins are sometimes called “fibular veins”; in fact, the Greek perone and the Latin fibula both started out meaning the clasp of a brooch and then became used to describe the bone in the leg (cf. the use of peroneus longus for fibularis longus).

Other names are indicative more of function or quality. The arteries were so called because they supply the brain, such that blocking them induces unconsciousness (Grk. “to stupefy”). The veins may get their name from the Greek word for “clear” or, perhaps more plausibly, from the Arabic cafin (“obscure”). The right and left veins were once thought to be linked directly to the liver and spleen respectively, giving them a perceived importance that earned them the imposing title of “royal veins."