The renal artery is a blood vessel which supplies oxygenated blood to the kidneys and adrenal glands. It arises from the abdominal aorta and runs into one of the two kidneys. The right renal artery is longer than the left and usually travels behind the inferior vena cava, measuring between 6 and 8 cm long; the length of the left can vary from 5 to 6 cm. Before reaching the hilum of the kidney, the renal artery divides into five branches, giving off some small inferior suprarenal branches to the adrenal glands (suprarenal glands), the ureter, and the surrounding cellular tissue and muscles.
Although there are usually two renal arteries (one for each kidney), one or two accessory renal arteries are sometimes found, especially on the left, coming off the aorta above or below the main renal artery. Instead of entering the kidney at the hilum, they usually pierce the upper or lower part of the organ. Thus, doubled renal arteries occur in 10% of cases. They may be side by side, one in front of the other, or spaced so that they enter the kidney at opposite ends of the hilum. In cases of doubled renal arteries, there may be a primary aortic hilar renal and an anterior or posterior division (vessel) or a renal polar artery.