The livers we looked at in the cadavers were just as you described. A grain of sand would be 100'sof times larger than many of the ducts. There are larger ducts but they are much closer to the gall baldder and as the instructor showed us a stone of 8 mm is all that it would take to plug up the largest of the bile ducts. I don't think people have ever seen a liver up close and personal so they don't realize how difficult it is to believe that someone could have 100's and 1000's of stones in this organ. There just ain't no place for them to fit.