The renal arteries are paired arteries that supply the

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

s with

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

. 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 In cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols Q, \dot Q, or \dot Q_ , edited by Catherine E. Williamson, Phillip Bennett is the volumetric flow rate of the heart's pumping output: tha ...

can pass through the renal arteries to be filtered by the kidneys.

Structure

The renal arteries normally arise at a 90°

angle In Euclidean geometry, an angle can refer to a number of concepts relating to the intersection of two straight Line (geometry), lines at a Point (geometry), point. Formally, an angle is a figure lying in a Euclidean plane, plane formed by two R ...

off of the left interior side of the abdominal aorta, immediately below the superior mesenteric artery. 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 aorta ( ; : aortas or aortae) is the main and largest artery in the human body, originating from the Ventricle (heart), left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at ...

, the

inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the ...

, and the kidneys, the right renal artery is normally longer than the left renal artery. * The right passes behind the

, the right renal vein, the head of the pancreas, and the descending part of the

duodenum The duodenum is the first section of the small intestine in most vertebrates, including mammals, reptiles, and birds. In mammals, it may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest p ...

. 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 In human anatomy, the splenic vein (formerly the lienal vein) is a blood vessel that drains blood from the spleen, the stomach fundus and part of the pancreas. It is part of the hepatic portal system. Structure The splenic vein is formed from ...

, and is crossed by the

inferior mesenteric vein In human anatomy, the inferior mesenteric vein (IMV) is a blood vessel that drains blood from the large intestine. It usually terminates when reaching the splenic vein, which goes on to form the portal vein with the superior mesenteric vein (SMV) ...

Branches

Before reaching the hilus of the kidney, each artery divides into four or five branches. The anterior branches (the upper, middle, lower and apical segmental arteries) lie between the renal vein and

ureter The ureters are tubes composed of smooth muscle that transport urine from the kidneys to the urinary bladder. In an adult human, the ureters typically measure 20 to 30 centimeters in length and about 3 to 4 millimeters in diameter. They are lin ...

, 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

, 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 (more common) or below the main artery. Instead of entering the kidney at the hilus, they usually pierce the upper or lower part of the organ.

Variation

The arterial supply of the kidneys is variable and there may be one or more renal arteries supplying each kidney. It is located above the renal vein. Supernumerary renal arteries (two or more arteries to a single kidney) are the most common renovascular anomaly, occurrence ranging from 25% to 40% of kidneys. Aberrant renal arteries may be present, and may complicate surgical procedures.

Clinical significance

Stenosis

Renal artery stenosis, or narrowing of one or both renal arteries will lead to hypertension as the affected kidneys release renin to increase blood pressure to preserve perfusion to the kidneys. RAS is typically diagnosed with duplex ultrasonography of the renal arteries. It is treated with the use of balloon angioplasty and stents, if necessary.

Atherosclerosis

Atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...

can also affect the renal arteries and can lead to poor perfusion of the kidneys leading to reduced kidney function and, possibly,

renal failure Kidney failure, also known as renal failure or end-stage renal disease (ESRD), is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney fa ...

Renal artery aneurysm

A dilated renal artery measuring twice its normal size indicates a renal artery aneurysm.

Trauma

A renal artery is damaged in 4% of blunt traumas and 7% of penetrating traumas to the

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

Additional images

File:Volume rendered CT scan of abdominal and pelvic blood vessels (smaller).gif, Volume rendered

CT scan A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

of abdominal and pelvic blood vessels. File:Gray1123.png, The posterior surfaces of the kidneys, showing areas of relation to the parietes. File:Slide4nn.JPG, Renal artery File:Slide7pp.JPG, Renal artery File:Slide10iii.JPG, Renal artery File:Slide2kkk.JPG, Renal artery

References

External links

* * - "Posterior Abdominal Wall: Branches of the Abdominal Aorta" {{Authority control Arteries of the abdomen