Interlobar and arcuate arteries and The renal veins and their tributaries

By Supriyadi Pro -
Interlobar and arcuate arteries - Each segmental artery breaks up into a number of interlobar arteries which run in close relation to the calyceal walls and enter the renal substance proper in the vicinity of the renal columns of Bertin. At this point, or sometimes before, they break up to form arcuate arteries (Fig. 1.2). Both interlobar and arcuate arteries give branches which ramify in the fat and connective tissue around the pelvis and calyces to form an important plexus which will be described later.

The arcuate vessels branch out from the interlobar arteries, their arched form being due to the fact that they run in a plane that corresponds approximately to the cortico-medullary junction (Figs 1.2, 1.3 and 1.4/Read: Cortical vessels). They are not, however, an accurate guide to this junction since a number of glomeruli lie on the medullary side of them, the corresponding afferent arterioles arising directly from the arcuate arteries themselves.

The branching out of the interlobar into arcuate arteries takes place in three dimensions, like the spokes of an Open umbrella, so that the angiographic appearance of these vessels is rather misleading.

Although the terminations of individual arcuate arteries lie very close to each other, they do not anastomose to form arcades but end by turning up through the cortex towards the surface of the kidney to become one or more interlobular arteries. Numerous other interlobular arteries arise from their convex surface along their length.

Picture: Microfil injection of the system
Fig. 1.2: Microfil injection of the system of the human kidney. The arrows indicate the line of attachment of the calyx.

The renal veins and their tributaries
The arcuate veins accompany the arcuate arteries but, unlike the latter, anastomose one with another so that true venous arcades are formed within the kidney although some of these anastomoses may not’ be very large.
Picture: Diagram of the arrangement of the intrarenal blood vessels
Fig. 1.3: Diagram of the arrangement of the intrarenal blood vessels.
The ascending and descending vasa recta are shown separately,
but in fact they are intermingled to form vascular bundles.
From Moffat (1975), by permission of Cambridge University Press.

The arcuate veins drain into interlobar veins which, in turn, usually unite to form three major veins, an upper, a middle and a lower. These three unite to form the renal vein. Aberrant renal veins are much less common than aberrant arteries but they do occasionally occur.
Read the full article: The Anatomy of the Renal Circulation

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