<prompt> A gallstone gets impacted most commonly in which pa of common bile ductSupra duodenalRetro duodenalAmpulla of vaterCommon hepatic duct  <response>: Most gallstones pass out of body unnoticed, but some become lodged in the common bile duct, causing jaundice A frequent site of gallstone impaction is the ampulla of vater, where common channel meets the small intestine Blockage of the common channel by a gallstone can induce acute pancreatitis Ref: Internet sources 