Renal artery
The renal arteries are paired arteries that supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle.
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.
Structure
In typical anatomy, the renal arteries arise perpendicularly from the sides of the abdominal aorta, just below the origin of the superior mesenteric artery at the L1-L2 vertebral level. They have a radius of approximately 0.25 cm, 0.26 cm at the root. The measured mean diameter can differ depending on the imaging method used. For example, the diameter was found to be 5.04 ± 0.74 mm using ultrasound but 5.68 ± 1.19 mm using angiography.Due to the anatomical position of the aorta, the inferior vena cava, and the kidneys, 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. It’s somewhat lower than the left one.
- Left artery lies behind the left renal vein, the body of the pancreas and the splenic vein, and is crossed by the inferior mesenteric vein.
Branches
Before reaching the hilus of the kidney, each artery divides into four or five branches. The anterior branches lie between the renal vein and ureter, the vein being in front, the ureter behind. The posterior branches, which are fewer in number and include the posterior segmental artery, are usually situated behind the ureter.Each vessel gives off some small inferior suprarenal branches to the suprarenal gland, the ureter, and the surrounding cellular tissue and muscles.
One or two accessory renal arteries are frequently found, especially on the left side since they usually arise from the aorta, and may come off above or below the main artery. Instead of entering the kidney at the hilus, they usually pierce the upper or lower part of the organ.