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Is a vascular apparatus of black blood, situate in the abdomen, and resulting from two distinct orders of vessels, united into one common trunk. 1. One of these trunks, much more extensive than the other, has received the; name Vena porta abdomina' lis, because it arises from all the organs enclosed in the cavity of the abdomen, except the kidneys and bladder; and; in the female, the uterus. The Abdominal vena porta has two principal roots, the splenic vein and the superior mesenteric, which have their ramifications in all the digestive organs. 2. The other trunk, destined solely to the liver, has been called the Hepat'ic vena porta. It appears to be a continuation of the abdominal vena porta, and proceeds towards the inferior surface of the liver. Opposite the transverse fissure of that organ, it divides, like an artery, into two branches, which, by their union, seem to form a canal or duct, called by some the Sinus of the vena porta, or of the portal vein. These branches are distributed in the substance of the liver, whither they are accompanied by a prolongation of the fibrous capsule of that organ, - the capsule of Glisson. The different branches of the vena porta are devoid of valves. See Liver.