Blood vessel prevent backflow as a result of a decrease in blood pressure as the blood passes through the circulatory system. There are various kinds of blood vessels: They are roughly grouped as "arterial" and "venous", determined by whether the blood in it is flowing "away from" (arterial) or "toward" (venous) the heart. The term "arterial blood" is nevertheless used to indicate blood high in oxygen, although the pulmonary artery carries "venous blood" and blood flowing in the pulmonary vein is rich in oxygen. This is because they are carrying the blood to and from the lungs, respectively, to be oxygenated. Blood
Paraumbilical vein shunting blood to the superficial epigastric vein. The superficial epigastric vein drains to the femoral vein which ultimately drains into the inferior vena cava directly through the external iliac and common iliac vein, thereby bypassing the liver. Dilation of this particular portacaval anastomosis results in what is referred to as caput medusae. Paraumbilical vein In the course of the round ligament of liver, small veins (paraumbilical) are found which establish an anastomosis between the veins of the anterior abdominal wall and the hepatic portal, hypogastric, and iliac veins. The best marked of these small veins is one which commences at