Renal Pelvis

Abstract

The renal pelvis collects the urine which flows out of the collecting tubes where they terminate at the renal papillae. The renal pelvis is the expanded upper of the ureter. As a rule it is partly inside and partly outside the renal sinus. According to current thinking the renal calyces are part of the renal pelvis, as they resemble it in structure. The old term “anatomical pelvis” or “true pelvis” has been extended in clinical usage by inclusion of the calyces and the phrase “pelvicalyceal system” is sometimes used by clinicians. One or more renal papillae discharge urine into each of the minor calyces (4–18 in number) and these in turn empty into the major calyces (2–3 in number). The major calyces are arranged in two rows: anterior and posterior.