Platyhelminthes are also known as flatworms because they are worms with a flat body. This is the main external morphological feature that differentiates them from nematodes (roundworms).
Even though 85 percent of kidney stones are small enough to pass during urination, fewer than 50 percent of patients chose this option. A person with a normal-size ureter can usually pass a kidney stone with a diameter less than 5 mm (about 3/16 of an inch) without significant pain or risk of kidney damage.
What is the largest kidney stone on record? The Guiness Book of World Records records; Peter Baulman (Australia) had a kidney stone removed from his right kidney in December 2003 at The Gold Coast Hospital, Southport, Qâ¦ueensland, Australia, weighing 356 g (12.5 oz) and measuring at its widest point, 11.86 cm (4.66 in).