Calculus (Medicine)

In medicine, a calculus, commonly called a stone, is a hard concretion, usually of mineral salts, that forms within an organ or duct of the body, a process known as lithiasis. Calculi form in many different organ systems: kidney and bladder stones in the urinary tract, gallstones formed from bile salts and cholesterol in the biliary system, salivary calculi in the salivary glands, prostatic calculi in the prostate, and enteroliths or gastric calculi in the digestive tract, along with microcalcifications that can form in breast tissue. Many calculi cause no symptoms and are found incidentally, but depending on their size and location they can cause pain, inflammation, obstruction of normal fluid flow, and a higher risk of infection, so the term covers a shared pathological process that spans several organ systems rather than one single disease.