What is osteonecrosis? Your bones are made up of living cells that need a blood supply to stay healthy. In osteonecrosis, blood flow to part of a bone is reduced. This causes death of bone tissue, and the bone can eventually break down and the joint will collapse. Osteonecrosis can happen to any bone, but most often it develops in the ends of long bones, such as the: Thigh bone. Upper arm bone. Less often, the bones of the elbows, ankles, feet, wrists, and hands are affected. When the disease involves part of a bone in a joint, it can
What is fibromyalgia? Fibromyalgia is a long-lasting disorder that causes pain and tenderness throughout the body. It also can cause you to feel overly tired (fatigue) and have trouble sleeping. Doctors do not fully understand what causes fibromyalgia, but people with the disorder are more sensitive to pain.