(A) (Triple phosphate) (1292 - Baily and Love 26th)80% patients with nephrolithiasis from calcium stone (Primarily of calcium oxalate or less commonly calcium phosphate)."Ureteric colic" - typically the patient is sized with sudden pain starting in the waist and radiating down to testis growing or inner side of thigh (distribution of genitofemoral nerve L1 & L2). The testis on the affected side may be pulled up.Types of renal calculus1. Oxalate calculus (Calcium oxalate) Calcium monohydrate stone is very hard and absorb x-ray it is seen radiologically2. Phosphate calcium struvite (phosphate, ammonium magnesium phosphate)* The stones grow in alkaline urine especially when proteus organism presents which split urea to ammonium.* Stag horn calculus - large, easy to see on radiographic films.3. Uric acid and urate calculi: Multifacted appearance Radiolucent, forms in Acidic urine.4. Cystine calculi - UTI of congenital error of metabolism that leads to cystinuria.* Hexagonal, translucent white appears only in acid urine.* Radio Opaque - because of sulphur that they contain and they are very hard5. Xanthine calculi: - Smooth, brick red in colour, show lamellation on cross-section.Struvite stones - (magnesium - ammonium phosphate stone) that form from secondary to urea - splitting organisms.Vesical Stone: common in visical schistosomiasis or in association with radiation cystitis. Foreign bodies. Most stones contain uric acid or struvite (in infected urine)Spiral (helical) CT has become the first study of choice (930 - CSDT 13th)"Meniscus sign" on cholangiography - CBD stone.* Commonest cause of surgical Jaundice is - CBD - stone.* Commonest type of carcinoma gall bladder with gall stones is Adenocarcinoma.* Most common cause of biliary structure is Trauma.* Incidence of gall stone is high in Ileal resection (mainly cholesterol stones).Urinary stonesAll individuals with urinary stones should undergo radiological investigation; following radiological modalities are used:1. Plane abdominal X-ray ("KUB" or kidney - ureter - Bladder X-ray): The first radiological test that is performed is the plain abdominal X-ray. Because majority of stones (90%) are radioopaque, these can be easily identified on X-ray:a) Radiolucent stones: Uric acid stone, Orotic acid stone, Xanthine, Trimterens, Dihydroxyadenine.b) Radioopaque stones: Cystine, Struvite, calcium oxalate, calcium phosphate2. Intravenous pyelogram (IVP): IVP can demonstrate urinary obstruction from renal stone and can demonstrate the position of non-opaque (radiolucent) stones.3. CT scan: Non contrast helical CT is 95 to 100% sensitive and specific for detection of renal calculi and, therefore, is the imaging modality of choice for urinary stones.4. USG: USG provide excellent assessment of kidney and bladder but inferior to IVP and CT scan in evaluation of the uterus.