Endometriosis is a common medical condition affecting an estimated 89 million women of reproductive age around the world.citation needed] In endometriosis, the tissue that lines the uterus (the endometrium, from endo, "inside", and metra, "womb") is found to be growing outside the uterus, on or in other areas of the body. Normally, the endometrium is shed each month during the menstrual cycle; however, in endometriosis, the misplaced endometrium is usually unable to exit the body. The endometriotic tissues still detach and bleed, but the result is far different: internal bleeding, degenerated blood and tissue shedding, inflammation of the surrounding areas, pain, and formation of scar tissue may result. In addition, depending on the location of the growths, interference with the normal function of the bowel, bladder, small intestines and other organs within the pelvic cavity can occur. In very rare cases, endometriosis has also been found in the skin, the lungs, the diaphragm, and the brain.citation needed] It is also very painful.