- Closed (i.e. simple) or open (i.e. compound). If the skin overlying the fracture is intact, the fracture is 'closed', whereas if it is breached then the fracture is called 'open'.
- A complete fracture occurs when the fracture cuts right through the bone - the periosteum on both sides is severed. Complete fractures can be further classified as being transverse, oblique, linear or spiral. These terms refer to the direction of a complete fracture relative to the long axis of the bone. They are pretty self-explanatory.
- An incomplete fracture occurs when a fracture only goes part of the way through the bone. A more succinct way of saying this is to state that the periosteum on at least one side remains intact. Incomplete fractures can be subdivided: A greenstick fracture occurs when the bone is bent or buckled but the fracture is incomplete - this is common in children. A stress fracture is a small crack in a bone's cortex due to repetitive strain on it. A compression fracture is a fracture of cancellous bone, and is commonly seen in vertebral bodies.
- A comminuted fracture is one in which there are more than two fragments of bone.
- A pathological fracture is a fracture that occurs through abnormal bone. Examples of processes causing abnormal bone include osteoporosis, Paget's disease and bone tumours.
You can see a nice picture of many of the above examples here.