Urinary calculi are solid particles like stones in the urinary system. They can develop anywhere along your urinary tract, which consists of these parts:
Urinary calculi may remain within the renal parenchyma or renal collecting system or be passed into the ureter and bladder. During passage, calculi may irritate the ureter and may become lodged, obstructing urine flow and causing hydroureter and sometimes hydronephrosis. Common areas of lodgment include the following: