Variant origin of superior polar artery and unusual hilar branching pattern of renal artery with clinical correlation.

Classically, a single renal artery arising from the abdominal aorta supplies the respective kidney on each side. Near the hilum of the kidney each renal artery divides into anterior and posterior branchs, which in turn divide into segmental arteries supplying the different renal segments. A total of 84 formalin fixed cadavers (73 male and 11 female, 168 kidneys in total) constituted the material for the study. During routine abdominal dissection conducted for medical undergraduates, the kidneys and their arteries were explored and variations in morphological patterns of renal arteries were noted. We observed superior polar renal artery in 22.6% cases. Superior polar renal arteries had different sources of origin. In 10.7% of cases it came directly from the abdominal aorta as an accessory renal artery; in 5.4% of cases as a direct branch from the main renal artery; in 3.6% of cases from the superior hilar renal artery (from one of the duplicated renal arteries); and in 3.0% of cases from a segmental branch of the renal artery. We also observed unusual hilar branching patterns of renal arteries, which included a fork pattern in 11.3% of cases, ladder pattern in 7.7% of cases, net pattern in 5.9% of cases, and triplicate in 3.0% of cases. Understanding the anatomy of vascular variations of the kidney is essential for the clinician to be able to perform procedures such as renal transplantation, interventional radiological procedures, and renal vascular operations more safely and efficiently.