The omasum can be found on the right side of the cranial portion of the rumen.[3] The omasum receives food from the reticulum through the reticulo-omasal orifice[3] and provides food to the abomasum through the omaso-abomasal orifice.[4] The omasum is spherical[5] to crescent shape[6] and has multiple leaflets similar to that of a book[7] called omasal laminae.[4] The omasal laminae are made of thin muscular layers covered with a nonglandular mucous membrane.[4] The omasal laminae come from the sides of the large curvature and project towards the inside of the omasum, extending from the reticulo-omasal orifice to the omaso-abomasal orifice.[8][4] The laminae greatly increase the surface area of the omasum.[3][9] The laminae are covered in omasal papillae that are claw like in some ruminants or blunt cones in others.[4][8] These papillae further increase the surface area but they also provide increased friction against the food particles.[3]