08.Here is a kidney with much more advanced hydronephrosis in which there is only a thin rim of remaining renal cortex. Such a kidney is non-functional and a source for ongoing infection. If this process is unilateral, then the problem originates from the ureteral orifice up to the pelvis. In this case, a large "staghorn" calculus (so named because the prominent projections of the stone into the calyces resemble deer antlers) was present that filled up the pelvis and calyceal system. If this process were bilateral, then the problem would originate in the bladder trigone or urethra (or the prostate around the urethra) or some process (such as a large neoplasm) that could impinge on both ureters.