<prompt> Most common site of gall stone impaction isDuodeno-jejunal junctionProximal to ileocaecal junctionDistal to ileocaecal junctionColon  <response>: Gall stone ileus It is an acute intestinal obstruction, often seen in elderly and is due to Blockage be a bolus or mass of gallstones which commonly enter the intestines through cholecystoduodenal fistula 75 or rarely through cholecystointestinal or gastric fistula MC site : Between gallbladder and duodenum 2nd MC site : Between gallbladder and transverse colon Obstruction is seen in Distal ileum or proximal to ileocaecal junction Ref: SRBs Manual of Surgery 5th edition Pgno : 648 