A branched renal stone formed in the image of the collecting system of the kidney (see KIDNEYS). It ?lls the calyces and pelvis and is commonly associated with an infection of the urine, particularly Proteus vulgaris. The calculus may lead to pyonephrosis and an ABSCESS of the kidney.
a branched stone forming a cast of the collecting system of the kidney and therefore filling the calyces and pelvis. The stone is usually associated with infected urine, the commonest organism being Proteus vulgaris. The combination of obstruction and infection can cause *pyonephrosis and, if neglected, a *perinephric abscess. Treatment involves a *percutaneous nephrolithotomy.
A hard, crust-like deposit (also known as tartar) found on the crowns and roots of the teeth. Calculus forms when mineral salts in saliva are deposited in existing plaque. Supragingival calculus is a yellowish or white deposit that forms above the gum margin, on the crowns of teeth near the openings of salivary gland ducts. Subgingival calculus forms below the gum margin and is brown or black. Toxins in calculus cause gum inflammation (see gingivitis), which may progress to destruction of the supporting tissues (see periodontitis). Calculus is removed by professional scaling. Attention to oral hygiene reduces recurrence.... calculus, dental