what is the calculi
Calculus, renal: A stone in the kidney (or lower down in the urinary tract). Also called a kidney stone. The stones themselves are called renal caluli. The word calculus (plural: calculi) is the Latin word for pebble. Renal stones are a common cause of blood in the urine and pain in the abdomen, flank, or groin. Kidney stones occur in 1 in 20 people at some time in their life. The development of the stones is related to decreased urine volume or increased excretion of stone-forming components such as calcium, oxalate, urate, cystine, xanthine, and phosphate.