An adult human has about 206 bones. These bones come in all shapes and sizes. As people grow, the bones in their bodies are very much alive. Bones are growing and changing along with the person. One way they change is that bones in a young child are very soft, but as people get older, their bones gradually harden. Bones are fully grown and have reached their maturity when someone reaches the age of 25. Bones have a number of different , but two of the most important are that bones provide support and protection for the body. Bones give the body its shape and also protect organs like the heart, lungs, and brain. Human bones are very strong, but, no matter how strong bones are, sometimes they break. A bone is called a fracture, which can be very painful. When people fracture a bone, they go to the doctor, who will try to fix the fracture. For a while it hurts to move the injured part of the body; but fortunately, a doctor can fix a broken bone and make the person feel better. The first thing a doctor will do is to take an x-ray to see where the break is. An is a picture, taken by a special machine, of the inside of your body. Once the doctor has an x-ray, he can see what a person’s bones look like and if one is broken. If it is a complex fracture, the doctor might have to operate to put the pieces back together before putting on a cast. If it is a simple fracture, many times the doctor can use the to keep the bones in the right place so they can heal. A cast is made of wet bandages put around the part of your body with the break, and the harden so the bones cannot move.