<P> Some common principles (below) apply to stones at any location, but for specifics see the particular stone type in question . </P> <P> Calculi are not to be confused with gastroliths . </P> <Ul> <Li> Calculi in the urinary system are called urinary calculi and include kidney stones (also called renal calculi or nephroliths) and bladder stones (also called vesical calculi or cystoliths). They can have any of several compositions, including mixed . Principal compositions include oxalate and urate . </Li> <Li> Calculi of the gallbladder and bile ducts are called gallstones and are primarily developed from bile salts and cholesterol derivatives . </Li> <Li> Calculi in the nasal passages (rhinoliths) are rare . </Li> <Li> Calculi in the gastrointestinal tract (enteroliths) can be enormous . Individual enteroliths weighing many pounds have been reported in horses . </Li> <Li> Calculi in the stomach are called gastric calculi (gastroliths). </Li> <Li> Calculi in the salivary glands are called salivary calculi (sialoliths). </Li> <Li> Calculi in the tonsils are called tonsillar calculi (tonsilloliths). </Li> <Li> Calculi in the veins are called venous calculi (phleboliths). </Li> <Li> Calculi in the skin, such as in sweat glands, are not common but occasionally occur . </Li> </Ul> <Li> Calculi in the urinary system are called urinary calculi and include kidney stones (also called renal calculi or nephroliths) and bladder stones (also called vesical calculi or cystoliths). They can have any of several compositions, including mixed . Principal compositions include oxalate and urate . </Li>

Where can stones be found in the body