Vein limbs. The Thebesian veins within the myocardium of the heart are valveless veins that drain directly into the chambers of the heart. The coronary veins all empty into the coronary sinus which empties into the right atrium. The dural venous sinuses within the dura mater surrounding the brain receive blood from the brain and also are a point of entry of cerebrospinal fluid from arachnoid villi absorption. Blood eventually enters the internal jugular vein. "Phlebology" is the medical specialty devoted to the diagnosis and treatment of venous disorders. A medical specialist in phlebology is termed a phlebologist. A related image
Heart the heart, ancient Greeks are considered to have been the primary seat of scientific understanding of the heart in the ancient world. Aristotle considered the heart to be organ responsible for creating blood; Plato considered the heart as the source of circulating blood and Hippocrates noted blood circulating cyclically from the body through the heart to the lungs. Erasistratos (304–250 BCE) noted the heart as a pump, causing dilation of blood vessels, and noted that arteries and veins both radiate from the heart, becoming progressively smaller with distance, although he believed they were filled with air and not blood. He