<prompt> Sphincter of Lutkans seen inCystic ductCommon bile ductPancreatic ductAmpulla of vater  <response>: The mucosa of the cystic duct is arranged in spiral folds known as the valves of Heister and the wall is surrounded by a sphincteric structure called the sphincter of Lutkens.The mucous membrane contains indentations of the mucosa that sink into the muscle coat; these are the crypts of Luschka.Ref: Bailey and Love 27th edition Pg: 1188 