Fractures, commonly known as broken bones, occur when a 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.