The renal arteries, two, arise on the side faces from the abdominal aorta, a little below the anterior mesenteric artery, on the level of the second lumbar vertebra. Their volume is important their diameter can reach 8 millimeters. Generally the renal arteries are detached at the same level, sometimes the left renal artery arises on a higher level. It is traditional to say that the arteries move horizontally outwards but the assertion is not absolutely exact: indeed, these arteries move obliquely bottomward, forming with the aorta an acute angle which can go down up to 45 degrees. In addition to this obliqueness in the frontal plan, the renal artery follows a curve of a posterior concavity which adapts to the convexity of the vertebral body this curve is more marked on the right than on the left.
The length of the two arteries is different the right artery measures on average a centimeter more than the left.
Relations of the renal arteries
The former face of these arteries is always masked by large venous trunks which are on the left, the renal, rather bulky vein to overflow the arterial trunk in top and bottom on the right, a renal vein much shorter, and, inside it, the trunk of the lower vena cava almost perpendicular to the artery. The posterior face of the renal arteries rests on the lumbar column, on the level of the point where come to fit bottom fibers of the pillars of the diaphragm it is separated on the left, by anastomosis between the renal vein,the small azygos and a lumbar vein, réno-azygo-lumbar trunk of Lejars.
Between the osseous artery and plan is a cellulous layer in which one finds a plexus nervous very abundant, lymphatic ganglia and an ascending lumbar vein, origin of the azygos veins.At some distance from the bile, the renal arteries are divided into several branches which penetrate separately in the renal parenchyma they will be studied at the same time as the kidney.
Branches of the renal arteries
In their way, the renal arteries give branches which go to the fat atmosphere of the kidney, the small basin and the upper part of the ureter. Their collateral branch most important and most constant is the lower capsulary artery.
Lower capsulary artery
This artery arises from the higher surface of the renal artery it moves on top, applied immediately to the corresponding pillar of the diaphragm. The capsulary of the right-side is placed immediately behind the vena cava the left is covered by the peritoneum.
On the two sides, the capsulary is with a few millimeters inside the semi-lunar ganglion of many branches of the sympathetic nervous system crossing it obliquely. On the level of the interior angle of the suprarenal capsule, the artery gains the posterior face of the body and anastomosis there with the average capsular, connects aorta, with the higher capsular, connects diaphragmatic the lower. All these branches form a surface network which are detached from the branches which penetrate the fabric of the capsule.
The two renal arteries can arise by a joint base. They can follow an abnormal way. The right renal artery has been seen passing in front of the lower vena cava. The origin of one or the two renal arteries can be deferred higher or low. This abnormal origin can be associated or not with kidney ectopic.
The renal ones can provide abnormally the lower phrenic artery, the hepatic artery, of the colic arteries, pancreatic, spermatic additional, an anastomotic branch which goes down in front of the psoas and is thrown in the iliac intern, an additional vesical artery, the crowned average one.
Additional renal arteries
The existence of additional renal arteries is a very frequent anomaly. The number and the volume of these renal accessories are more variable.
When there is only one, its volume can reach and even exceed that of the normal renal artery. These additional renal arteries were especially met on subjects of which the kidneys had preserved their fetal multi-lobaire provision; they can also be distributed to normally formed kidneys. The additional renal arteries form three distinct groups when they are born from the abdominal aorta in the vicinity of the normal renal artery, they are probably related to the segmentation in distinct lobes which the fetal kidney presents; when they are born from the close arteries (mesenteric higher, hepatic, splenic, etc), one can, more logically, regard them as resulting from the abnormal development of the unimportant small arteries which normally send to the kidney or its capsule your arteries in question; or even they are associated with a displacement of the kidney.