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 average size of a kidney stone?   I'm not sure. I just had a 4 ml and 7 ml removed from my right kidney, they're smaller then the one in my left kidney, and my roommate had a 3.5 ml stone. I was told theâ¦ 7 was extremely large and they had to put a stent in me after taking them out.