Question

Write about the mechanism and healing of bone fracture.

Answer 1

Mechanism and healing of a bone fracture: There are four major stages in repairing a simple fracture.

1. Formation of haematoma - When a bone breaks the blood vessels in the bone and surrounding tissues are torn and results in a haemorrhage. Due to this a haematoma, a mass of clotted blood forms at the fracture site.
2. Formation of fibrocartilaginous callus - Within a few days several events lead to the formation of soft granulation tissue called callus. Capillaries grow into the haematoma and phagocytic cells invade the area and begin to clean up the debris.
3. Formation of Bony callus - New bone trabeculae begin to appear in the fibrocartilaginous callus. Gradually that is converted into a bony (hard) callus of spongy bone.
4. Remodeling of Bone - Bony callus formation will be continued for several months. After that the bony callus is remodelled. The excess material on the diaphysis exterior and within the medullary cavity is removed and the compact bone is laid down to reconstruct the shaft walls.