Illustrated Encyclopedia of Human Anatomic Variation: Opus II: Cardiovascular System: Arteries: Abdomen

Renal Arteries

Ronald A. Bergman, PhD
Adel K. Afifi, MD, MS
Ryosuke Miyauchi, MD
Peer Review Status: Internally Peer Reviewed

It is not only ludicrous but dangerous to suggest that the kidneys each receive only a single artery. This is commonly stated and shown in illustrations in textbooks of anatomy used by professional students of medicine and the allied health sciences. This could be easily rectified in a single sentence such as, "The kidneys may receive a single artery athough each organ may equally be supplied by as many as six end arteries." The details follow.

The right and left renal arteries may arise from the aorta by a common stem.

They may arise from the aorta at a lower point than usual, in which case the kidneys lie below their usual position.

There may be several renal arteries on each side, or the renal artery may divide, close to its origin, into several branches. The renal artery on one or both sides may arise from the bifurcation of the aorta or from the common iliac, internal iliac, inferior mesenteric, middle sacral, or from a common intercostal-renal trunk. The right artery may cross in front of, instead of behind, the vena cava.

Branches of the renal artery may "perforate" the substance of the kidneys instead of entering from the hilus (so called accessory branches.)

The renal artery may give rise to branches normally derived from other vessels, such as the inferior phrenic, hepatic, right renal, middle and inferior suprarenals, gonadal, pancreatic, some of the colic arteries, and one or more of the lumbar arteries.

"Accessory renal arteries," varying in size and generally derived from the aorta, are common (26 to 30% of all reported kidneys studied), and may enter the kidneys at almost any point. It is a misnomer to call such vessels accessory renal arteries because they are not extra but essential, tissue-sustaining arteries and cannot be ligated without dire cosequences.

Frequently, the renal arteries provide two to five slender branches to the suprarenal gland, whereas the inferior suprarenal arteries coming from the aorta or the renal arteries often supply one to four branches (capsular branches) to the superior pole of the kidney and its fat body.

The inferior phrenic artery sometimes also supplies an "accessory renal artery." A study of the arterial supply of the kidney (composite of 45 authors and 10,967 kidneys) demonstrated the following: Single artery to each kidney, 72% (SD 2.51; one artery with a single upper polar branch, 12.6% (412 of 3269 cases); two arteries, 11% (530 of 4901 cases); one hilar and one upper aortic polar branch, 6% (211 of 3384 cases); one hilar and one lower aortic polar branch, 3% (115 of 3674 cases); three arteries 1.7% (70 of 4019 cases); and two arteries, one with an upper polar branch, 2.7% (37 of 1370 cases.) Quain reported that three arteries occur in 3% of cases.

The inferior suprarenal arteries (one to three), which occur bilaterally, are constant branches of the single renal artery. An inconstant, but frequent (from 16 to 22% of cases depending on author) branch is the gonadal (ovarian or testicular) artery, a component of the renal pedicle. The inferior phrenic is another inconstant branch sometimes arising from the right renal artery or from an aortic superior renal polar artery. Because the inferior phrenic often supplies most or all of the blood to the suprarenal gland it must be identified and saved when surgery is performed on the renal pedicle to avoid dire circumstances.

In one study the renal arteries were reported to be located between the lower third of the first lumbar vertebra and the cranial third of the second lumbar vertebra. The right and left renal arteries were reported to be at the same level in about 30% of cases, while the right was higher in 47% and the left was higher in about 23% of cases. A single renal artery on one side and multiple (two, three, or four) renal arteries on the other is not unusual. There were no reported sex (gender) or race related differences.

The right renal artery is longer than the left and usually courses behind the inferior vena cava. When multiple renal arteries are present, the more caudal arteries often take a precaval course. The right renal artery, from aortic origin to its division point, can measure 0.5 - 8 cm long; the length of the left can vary from 0.5 - 6 cm. In most cases, a single renal artery divides into anterior and posterior trunks; that division might occur anywhere along the artery's course to the kidney hilum. Precocious (near to its origin) division may be interpreted - erroneously, as dual or even multiple renal arteries. Most commonly, there are four branches, but there can be two to five entering the parenchyma of the organ. Based upon their relationship to the renal pelvis (that is, on whether they represent anterior or posterior divisions of the artery), these branches have been termed the anterior superior, anterior medial, anterior inferior, and a fourth branch that usually runs posterior to the renal pelvis, the retropyelic branch.

The kidney has been shown to be composed of five segments, i.e., apical, upper, middle, lower and posterior. The three terminal branches of the anterior division of the renal artery are usually referred to as the upper, middle, and lower segmental (terminal) branches; the fourth (posterior) branch supplies the posterior segment. The apical segment of the organ is usually supplied by the anterior division, but in 10% of cases the posterior branch may also supply an apical artery.

According to Crelin, Eustachius made the first copperplate engraving illustrating a renal artery variation in 1564. Lancisi published the engravings with commentary in 1714 and referred to the variation as a "lusus naturae" (sport of Nature). The artery was related, but not identical, to Crelin's case. In Crelin's case, the artery arose from the right internal spermatic (gonadal) artery, 6 cm above the internal (abdominal or deep) inguinal ring.

So-called "accessory" or "supernumerary" renal arteries are present in about 30% of cases (based on a composite of 45 studies and 10,967 kidneys). These vary in number from two to four, although there may be, rarely, five or six, arranged either unilaterally or bilaterally. In 16% of subjects, there was variation in the number of renal arteries between kidneys in the same subject. Accessory renal arteries can arise from the aorta as high (superiorly) as the diaphragm or as low (inferior) as the internal iliac artery. A study by Sykes suggests, "a superior accessory artery is a separate apical artery and an inferior accessory artery is a separate lower segmental artery."

Doubled renal arteries occur in 10% of cases (based on 10,967 kidneys studied). 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.

Very rarely, the lower renal arises near the aortic bifurcation or from the common iliac. Sometimes one of the arteries passes in front of or behind the renal pelvis; the upper may cross the lower the lower renal and ureteropelvic junction to enter the inferior pole of the kidney.

In 1 - 2% of cases, three hilar renal arteries are derived from the aorta. The typical pattern for triple renal arteries is that two are hilar (of aortic origin) and the third is a superior or a lower renal polar branch. The superior or the intermediate of the three renals may supply a superior renal polar or a suprarenal branch. The inferior vessel may provide a gonadal (ovarian or testicular) or inferior renal polar.

The presence of four renal hilar arteries derived from the aorta is rare. This pattern arises from the aorta between the superior and inferior mesenteric arteries. The upper two vessels may have a postcaval course and the two lower may pass in front of the inferior vena cava. The upper two may pass in front of the renal pelvis and the lower two behind it.

Quadruple renals may exist as two hilar and two polar, three hilar and one polar, or one hilar and three polar renal arteries. Usually only one of these is large and the others are smaller and distributed to the superior or inferior extremities of the kidney.

"Accessory renal" arteries usually arise from the aorta, but they may also arise from: suprarenal celiac artery, superior mesenteric, inferior mesenteric, common iliac, middle sacral, or from the external iliac artery.

Poynter found, "no frequency differences in renal anomalies between the two sides, with the number of bilateral conditions constituting about half the cases, there were no sex differences, and with no relation between supernumerary arteries and veins; the latter being the rarer anomaly". Poynter also noted the wide discrepency in textbooks as to the frequency of multiple renal arteries and noted that 1883 specimens yielded 456 cases of multiple renal arteries and that individual investigators (Poynter cited 10 individuals) reported frequencies of 14 to 59% in the 465 of cases studied.

Variations of the Blood and Lymphatic Supply of the Kidney

Modified from Gutierrez, 1936.

Images 6 and 7, Image 13, Image 42, Image 69, Image 126A, Image 126B, Image 126C, Image 126D, Image 148, Image 162, Image 213, Image 219, Image 350A, Image 350B, Image 351, Image 353B, Image 353D, Image 401, Image 428A, Image 428B, Image 428C, Image 428D, Image 428E, Image 490, Image 491 Image 506

"Accessory"

See Image 69, See Images 126A-D, See Images 353A-D

Anterior Superior Capsulae Adipose

Image 218

Doubled

See above images for Renal

Hilar

See Image 42, See Image 126A

Inferior Polar

See Inferior Renal Polar Arteries

Intercosto-renalis

Image 407

Retropelvic

See above images for Renal

Superior Polar

See Superior Renal Polar Arteries

References:
Bachmann, D. and E. Haasner. (1965) Truncus Intercosto-renalis. Fortschr. Geb. Rontgenstr. Nuklearmed. 102:712-713.

Beaumanoir, (de Brest.), -. (1882) Anomalies artèrielles trouvées a l'autopsie d'un sujet. Bull. de la Soc. Anatomique de Paris 57:316-321.

Broca, -. (1849) Cinq anomalies artérielles sur le même subject. Anomalies rare des artères de l'avant--bras. Reflexions sur les anomalies artérielles du member thoracique (popliteal, renales, deux arteres humérals, femoral, tibio-peronier tronc). Bulletins et Mem. de la Société Anatomique de Paris XXIV(2):49-59.

Dufour, -. (1852) Trois artères vent se jeter dans le rein; une venant de l'aorte, et les deux autres de l'iliaque primitive. Bulletins et Mem. de la Société Anatomique de Paris XXVII(1):27.

Gillaspie, C., Miller, L. nd M. Baskin. (1916) Anomalous renal vessels and their surgical significance. Anat. Rec. 11:77-86.

Gray, G. M. (1906) Multiple renal arteries. Anat. Anz. 29:266-270.

Guggemos, E., Nyström, J. and S.J. Peppy. (1962) A rare case of an arterial connection between left and right kidneys. Ann. Surg. 156:940-943.

Harvey, R.A. (1914) A case of multiple renal arteries. Anat. Rec. 8:333-339.

Latarjet, A. (1931) Testut's Traité d'Anatomie humaine. Tome V., G. Doin & Cie., Paris.

Liégeois, -. (1857-1859) Anomalie double des artères rénales. Bulletins et Mem. de la Société Anatomique de Paris XXXIV(11):304-305.

Pilate, -. (1867) anomalie des artères rénales; Le rein droit reçoit quatre troncs arteriels; le rein gauche reçoit deux troncs. Bulletins et Mem. de la Societe Anatomique de Paris XLII(4):205.

Remaining References:

See Ureteral Arteries

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