The Aorta is usually divided into 4 sections. Ascending Aorta (between the heart and the aortic arch) Aortic Arch Descending Aorta (this is divided into 2 separate sections) Thoracic Aorta (above the diaphragm) Abdominal Aorta (below the diaphragm to the iliacs) Branches of the Abdominal Aorta Celiac Artery (separates into the Hepatic artery, Splenic artery and the left gastric artery) Superior Mesenteric Artery (SMA) Middle Suprarenal Artery (supplies the adrenal glands) Renal Artery Gonadal Artery (ovaries and testicles) Lumbar Artery (abdominal wall and spinal cord Inferior Mesenteric Artery Common Iliac (Branches to supply lower extremities and pelvis The Inferior Vena Cava (IVC) and Confluence The Inferior Vena Cava (IVC) is formed from the Common Iliac veins. It brings blood into the right atrium of the heart. Tributaries of the IVC Common Iliac Vein Lumbar Vein Gonadal Vein Renal Vein Suprarenal Vein Inferior Phrenic vein Hepatic Vein Portal Vein and Confluence The Portal vein is not a true vein in the fact the blood it carries does not go directly to the heart. The Portal vein drains the gastrointestinal tract and spleen. Tributaries of the Portal Vein Superior Mesenteric vein Splenic vein This union is also known as the splenic-mesenteric confluence. Less common tributaries Inferior Mesenteric vein Gastric vein Cystic veins Right before the Portal vein reaches the liver it branches into a right and a left vein. It continues branching once it is inside the liver until it composed of numerous portal venules. Biliary Vessels The Gallbladder is supplied by the Cystic artery. The Cystic artery is a branch of the Right Hepatic artery. The Gallbladder is drained by the Cystic vein which joins the right branch of the Portal Vein. The veins that drain the fundus and body of the Gallbladder typically pass directly into the liver but can drain into the Portal vein. Source