The renal arteries (Latin: sg. arteria renalis) are two lateral branches of the abdominal aorta that arise just inferior to the superior mesenteric artery between vertebrae L1 and L2 and supply the kidneys.
The renal arteries provide a large portion of the total blood flow to the kidneys. Up to a third of the total cardiac output can pass through these arteries to be filtered by the kidneys.
There are some differences between the right and left renal arteries. The right renal artery usually is longer than the left one. It is due to the position of the aorta, the inferior vena cava, and the kidneys in the human body. The right renal artery passes behind the inferior vena cava, the right renal vein, the head of the pancreas, and the descending part of the duodenum. The right artery also lies somewhat lower than the left one. The left renal artery, on the other hand, lies behind the left renal vein, the body of the pancreas and the splenic vein, and is crossed by the inferior mesenteric vein.
The renal arteries each divides into four or five branches before reaching the hilus of the kidney. Each artery also gives rise to some small inferior suprarenal branches to supply the suprarenal glands, the ureters, and some surrounding tissues.
Some individuals have accessory renal arteries (one or two), which is especially common on the left side. They usually arise from the aorta, travel above or below the main renal artery. Instead of entering the hilus of the kidney, these accessory arteries typically pierce the upper or lower part of the organ.