The ease with which a kidney stone can be expelled when it falls inside the bladder depends on the size, shape and smoothness of the surface of the stone.
In some cases, the kidney stone will migrate to the renal pelvis, then pass through the ureter and enter the bladder under the factors of urine flushing, peristalsis of the ureter and gravity of the stone itself. The diameter of the ureter is about 5 to 7 mm, while the diameter of the urethra is also about 5 to 7 mm in men and slightly wider in women.
The ureter and urethra have a certain degree of dilatancy, so a certain size of stone through the ureter, it is possible to pass through the urethra with the urine discharge.
If the stone is large, irregular in shape, not smooth or even have barbs on the surface, the probability of expulsion is smaller, and even have the risk of embedding, bleeding, infection and so on.
Kidney stones fall into the bladder, if the patient’s kidney function is good can drink more water to facilitate the smooth discharge of stones, pay attention to observation. If the stone is difficult to be discharged, you should actively go to the hospital for treatment under the guidance of the doctor.