"The renal pelvis is triangular in shape, lies posteriorly in the renal hilum surrounded by fat and vessels and is formed by either the union of two-to-three major calyces or of seven-to-eleven minor calyces. Thus, the renal pelvis can have numerous shapes, ranging between an ampulla-like single renal pelvis to one made of numerous funnel-shapes, but all types taper down to continue as the ureter."