Kidney stones, illustration - stock illustration

Kidney stones. Computer illustration showing a section through a human kidney containing kidney stones (yellowish, right). The ureter (lower centre) that carries urine from the kidney to the bladder can also be seen. Kidney stones are solid accumulations of dissolved urinary minerals that have come out of solution and built up into hard stone-like objects. They typically leave the body without any symptoms when passing urine. However, if they grow to a sufficient size they may cause an obstruction in the urethra, leading to severe pain.