Vein they were for transport of air. The Greek physician, Herophilus, distinguished veins from arteries but thought that the pulse was a property of arteries themselves. Greek anatomist Erasistratus observed that arteries that were cut during life bleed. He ascribed the fact to the phenomenon that air escaping from an artery is replaced with blood that entered by very small vessels between veins and arteries. Thus he apparently postulated capillaries but with reversed flow of blood. In 2nd century AD Rome, the Greek physician Galen knew that blood vessels carried blood and identified venous (dark red) and arterial (brighter and thinner)
Patellar network Patellar network The patellar network (circulatory anastomosis around the knee-joint, patellar anastomosis, genicular anastomosis, articular vascular network of knee or rete articulare genus) is an intricate network of vessels around and above the patella, and on the contiguous ends of the femur and tibia, forming a superficial and a deep plexus. The arteries which form this plexus are the inferior medial and superior medial genicular arteries, the inferior lateral and superior lateral genicular arteries, the descending genicular artery, the descending branch of lateral femoral circumflex artery, and the anterior tibial recurrent artery. The genicular anastomosis provides collateral circulation to supply