Question

Which of the following is the most common renal vascular anomaly?

• A. Supernumerary renal arteries
• B. Supernumerary renal veins
• C. Double renal arteries
• D. Double renal veins

Hint:

Extra embryonic arteries that fail to regress are the commonest renal vessel variant.

Answer 1

The Correct Option is A

The answer comes straight from how the kidney's blood supply forms. As the kidney migrates upward in the embryo, it is supplied in turn by several small arteries; usually these wither away until just one renal artery remains. When one or more of those embryonic vessels fails to disappear, the kidney ends up with extra arteries, called accessory or supernumerary renal arteries.

This particular hiccup in development is common, far more so than having spare veins. That is why supernumerary renal arteries top the list of renal vascular anomalies, seen in a large fraction of normal kidneys at dissection or angiography.

They matter in practice. A lower-pole accessory artery may kink across the junction of the pelvis and ureter and obstruct urine drainage, producing hydronephrosis. Surgeons also respect them because each is an end artery; cutting one infarcts the segment of kidney it feeds, which is critical knowledge in transplant and nephron-sparing surgery.

Venous variants such as extra or doubled renal veins do occur but are less frequent than the arterial ones. Hence the most common renal vascular anomaly is supernumerary renal arteries.
\[\boxed{\text{Supernumerary renal arteries}}\]