Kidney Stones, also known as renal calculi, are hard masses that separate urine from the urinary tract. These stones can occur anywhere in the urinary tract, including the kidneys, bladder, ureters and urethra.
This fluid is called the cerebrospinal fluid (CSF). When it leaks out, the pressure around the brain and spinal cord drops. Causes of leakage through the dura include: 1  Certain head, brain, or spinal surgeries.  Head injury.
Brake fluid is one of the most dangerous leaks to worry about, our sister site Jalopnik points out. If you see that clear to brown and slick puddle under your car (it'll be even more slippery to the touch than engine oil or transmission fluid), don't even try driving it but get it towed right away.