Renal artery angiography in a 35-year-old woman with unexplained hypertension showing the typical "string-of-beads" sign (arrows) characteristic for FMD involving the lower left renal artery (accessory artery). The arrowhead indicates a small saccular aneurysm at the distal portion of right renal artery.
Source: Fibromuscular dysplasia in an accessory renal artery causing renovascular hypertension: a case report. Journal of Medical Case Reports 2007, 1:58. doi:10.1186/1752-1947-1-58