Bones are rigid, but they do bend or “give” somewhat when an outside force is applied. However, if the force is too great, the bones will break, just as a plastic ruler breaks when it is bent too far.
According to the American Academy of Orthopaedic Surgeons, how bad a fracture is usually depends on the force that caused the break. If the force that caused the bone to break is less, such as a fall, then the bone may crack rather than break all the way through. If the force is very high, such as in an automobile crash or a gunshot, then the bone may shatter.
If the bone breaks in such a way that bone fragments stick out through the skin, or a wound goes all the way down to the broken bone, the fracture is called an “open” fracture. This type of fracture is very serious because once the skin is broken, it may cause an infection in both the wound and the bone.