Which variation is most commonly observed in the anatomy of renal arteries?

The most commonly observed variation in the anatomy of renal arteries is the existence of multiple renal arteries. This anatomical variation occurs when there are more than one renal artery supplying a single kidney, which is a common finding in the general population. The presence of multiple renal arteries can be due to the embryological development of the renal system and is observed in a significant percentage of individuals.

In many cases, the additional renal arteries are found coming directly off the abdominal aorta or its branches, and they typically supply the lower parts of the kidney. Understanding this variation is important for surgical planning, imaging interpretation, and in the context of kidney disease, as it can influence the vascular supply to the kidney and may have implications during procedures such as nephrectomy or renal artery stenting.

The other variations mentioned, while clinically significant in certain contexts, are less common in the general population. A single renal artery represents the most typical finding rather than a variation. Renal artery aneurysms, although concerning and require clinical attention, are pathologies rather than variations. An absent renal artery is a rare anatomical defect that results in a single kidney's developmental anomalies and is not typically seen as a common variation like multiple renal arteries.