Superior Renal Polar Arteries

Superior renal polar arteries are usually single. They arise as separate branches from the aorta in 7% of cases, or as branches of the renal artery in 12% of cases. There may be two or three unilaterally or bilaterally with different aortic or renal sources. They often arise from an inferior suprarenal or from a branch of an inferior suprarenal, i.e., an adipose renal capsular branch to the kidney. Superior renal polar arteries can also arise from the inferior phrenic or from the superior mesenteric artery. Some superior renal polar arteries provide several branches to the suprarenal gland, dividing before entering the superior pole of the kidney.

Because they are often concealed or take a high course to the kidney, superior renal polar arteries can be damaged during surgical procedures. When such a vessel is torn, the consequences may be a massive fatal hemorrhage; when they are ligated, devascularized and necrotic areas will develop in the kidney. All renal arteries, including accessory or supernumerary renal arteries, are end-arteries in the strictest sense; there is no collateral arterial supply to or in the kidneys (Michels).