Unusual relationship of multiple renal arteries.

An unusual cross relationship of two left renal arteries was demonstrated angiographically during the investigation of a young man presenting with painless, total hematuria after a traffic accident. The upper pole artery arose from the aorta caudal to the lower pole artery. In the absence of a malrotation a possible embryologic cause has been advanced. It also highlights the advantage of combining selective renal arteriography with aortography when multiple renal arteries are encountered.