Jack stone calculi is seen in which anatomic pa

Jackstone calculi are primary bladder stones that have an appearance resembling toy jacks. They are almost always composed of calcium oxalate dihydrate and consist of a dense central core and radiating spicules . They are typically light brown with dark patches(due to deposited blood pigment ) and are usually formed in the urinary bladder and rarely in the upper urinary tract. On plain radiographs and computed tomography it appears as typical star shaped toy jack. Jackstones often must be removed cystolithotomy. Reference : page 1030 SRB's manual of surgery 5th edition