Rokitansky–Aschoff sinuses, also entrapped epithelial crypts, are pseudodiverticula or pockets in the wall of the gallbladder. They may be microscopic or macroscopic.
Histologically, they are outpouchings of gallbladder mucosa into the gallbladder muscle layer and subserosal tissue.
They are not of themselves considered abnormal, but they can be associated with cholecystitis.
They form as a result of increased pressure in the gallbladder and recurrent damage to the wall of the gallbladder. They are associated with gallstones (cholelithiasis).
They are named after Carl Freiherr von Rokitansky and Ludwig Aschoff.