Urinary stones or calculi are concretions formed within the urinary tract by the crystallization of one or more substances normally found within the urine. These calculi can be found anywhere within the urinary tract from the kidneys, ureters, and bladder. Most often these stones are formed within the kidney and travel down the ureter towards the bladder causing a sudden sharp intense pain along the flank which radiates towards the groin. Kidney stone pain is often intermittent and crescendo in nature and associated with nausea and vomiting. This complex of symptoms is commonly referred to as renal colic. Kidney stone patients often note difficulty finding a comfortable position and therefore move continuously to try to "shake off" the pain.