Fractures, commonly known as broken bones, occur when bone is not strong enough to sustain the force exerted on it. The four most common types of fractures are complete, incomplete, compound and simple. A complete fracture occurs when the bone breaks all the way through into two or more parts, while in an incomplete fracture the bone does not break all the way through. A compound fracture occurs when the bone breaks through the skin and a simple fracture happens when no open wound occurs. There are a variety of different treatments for fractures based on where the injury is located and how severe it is.