n. the presence of stones (calculi) in the urinary bladder. The stones are either formed in the bladder, due to obstruction, urinary statis, and infection (primary calculi), or pass to the bladder after being formed in the kidneys (secondary calculi). They cause pain, the passage of bloody urine, and interruption of the urinary stream and should be removed surgically. See calculus.
n. (pl. calculi) 1. a stone: a hard pebble-like mass formed within the body, particularly in the gall bladder (see gallstone) or anywhere in the urinary tract (see cystolithiasis; nephrolithiasis; staghorn calculus). Calculi in the urinary tract are commonly composed of calcium oxalate and are usually visible on X-ray examination. Some of these stones cause pain if they are associated with obstruction and prevent urine flow in the ureter or kidney, or by direct irritation of the bladder. Stones passing down a duct (such as the ureter) cause severe colicky pain. Most stones pass spontaneously, but some need to be broken into smaller pieces, usually by extracorporeal *lithotripsy, and the remainder by endosurgical techniques (see litholapaxy) or rarely by open surgery. Calculi may also occur in the ducts of the salivary glands. 2. a calcified deposit that forms on the surface of a tooth that is covered with dental *plaque as a result of poor oral hygiene. Supragingival calculus forms above the *gingivae (gums), principally in relation to the openings of the salivary gland ducts. Subgingival calculus forms beneath the crest of the gingivae. Calculus hinders the cleaning of teeth and its presence contributes to *gingivitis and *periodontal disease. A link has been demonstrated between increased calculus levels and infective *endocarditis.... calculus
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