The urinary system is made up of two kidneys, a ureter leading from each kidney to the bladder and the urethra, which carries urine from the bladder out of the body. Most stones are formed in the kidney and some can then travel down the ureter and into the bladder. Occasionally a stone will form in the bladder itself. If the stone is too large it may become lodged in a ureter. Stones if the kidney or ureter can cause blockage of urine flow or irritation to the urinary tract lining.
There are a number of theories surrounding the formation of kidney stones. Some people also appear to have a tendency toward stone formation for different reasons. Once you have formed a stone, there is an increased risk of you forming more stones.
The known predisposing factors to stone formation are:
Some known causes of stone formation include: