According to condition whether the end of fracture is open to outside, fractures can be classified into:
1. Closed fracture: The skin or mucosa of fracture region is not broken, and the end of fracture is not open to the outside.
2. Open fracture: The skin or mucosa is broken in the fracture part, the end of fracture is open to the outside.

According to the extent of fracture injury, fractures may be classified into:
1. Simple fracture: There is no injury of nerves, important blood vessels, tendons or organs.
2. Complicated fracture: There is the injury of nerves, important vessels, tendons or organs.
3. Incomplete fracture: The continuity of only the partial bone trabeculae is broken off. In this kind of fracture, generally, there is no displacement.
4. Complete fracture: The continuity of the bone trabeculae is broken off. A tubular bone is broken in two or more segments proximally and distally. There is usually fracture displacement.

According to the distribution of fracture lines, fractures may be classified into:
1. Transverse fracture: The fracture line and the diaphysis axis meet at a right angle or almost at a right angle.
2. Oblique fracture: The fracture line and the diaphysis axis meet at an acute angle.
3. Spiral fracture: The fracture line is spiroid.
4. Comminuted fracture: The bone is broken into more than three segments. If the fracture lines form a T-figure, it is called T-shaped fracture; or a Y-figure, called Y-shaped fracture.
5. Impacted fracture: It often occurs in the juncture of compact bone and spongy bone in the metaphysis of long tubular bones. After fracture, the end of compact bone impacts into spongy bone.
6. Compression fracture: The spongy bone changes its shape because of compression, such as fractures of vertebra and calcaneus.
7. Fissured fracture: It is also called bone fissure. The space of fracture looks like a fissure or a line. This kind of fracture usually occurs in cranial bone, scapula, etc.
8. Greenstick fracture: This often occurs in children. Only partial substance and periost of bone are drawn out, folded or cracked. There is in fracture region deformity of angulation or crookedness, just like the breaking of the twig.
9. Epiphysiolysis: It occurs in epiphyseal plate, the epiphysis and the diaphysis separate from each other. It usually occurs in children or youth.

According to the stability of the bone after reduction, fractures may be classified into:
1. Stable fracture: Usually, no displacement occurs again after reduction of fracture with a proper external fixation, such as fissured, greenstick, compression, and transverse fractures.
2. Unstable fracture: Displacement easily appears again after reduction, such as oblique, spiral, and comminuted fractures.

According to the time seeking for medical service, fractures may be classified into:
1. Fresh fracture: The first visit is made in two or three weeks after fracture.
2. Old fracture: The first visit is made two or three weeks later after fracture.

According to whether the substance of bone is normal before trauma, fractures may be classified into:
1. Traumatic fracture: The bone substance is normal before fracture, the fracture is absolutely caused by external forces.
2. Pathological fracture: The bone substance has already had lesion before fracture, the fracture is caused by a little force.