Model of Gall-stone

A gallstone or biliary calculus is a stone-like formation of variable
composition and shape. It is the result of a solution imbalance in the
bile, causing cholesterol, bilirubin and calcium to precipitate and form
crystals. Gallstones may occur in the gallbladder and the various bile
ducts. This model shows the anatomy of the biliary system and its
surroundings in half natural size and typical locations of gallstones.