Renal aa.

The renal arteries normally arise off the side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle with the aorta. The renal arteries carry a large portion of total blood flow to the kidneys. Up to a third of total cardiac output can pass through the renal arteries to be filtered by the kidneys.

Due to the position of the aorta, the inferior vena cava, and the kidneys in the body, the right renal artery is normally longer than the left renal artery. The right passes behind the inferior vena cava, the right renal vein, the head of the pancreas, and the descending part of the duodenum. The right is somewhat lower than the left. The left lies behind the left renal vein, the body of the pancreas and the splenic vein, and is crossed by the inferior mesenteric vein.