Discuss and discriminate between the sequence of steps chara

Discuss and discriminate between the sequence of steps characteristic of fracture healing.

Solution

The following steps occur in the repair of bone fracture.

1. Formation of fracture hematoma; As A result of fracture, Blood vessels crossing the fracture line are broken. These include vessels in the periosteum, osteons, medullary cavity and perforating canals.As blood leaks from torn blood vessels, It forms a clot around the site of fracture which is called a fracture hematoma. It usually forms 6-8 hours after the injury. Bone cells at the fracture site die. Swelling and inflammation occurs in response to dead bone cells which produce additional cellular debris. Blood capillaries grow into the blood clot and Phagocytes and osteoclasts begin to remove the dead or damaged tissue in and around the fracture hematoma.

2. Fibrocartilagenous call us formation; The Infilitration of new capillaries into fracture hematoma helps organize it into granulation tissue which is termed as procallus. Next fibroblasts ,osteogenic cells and red bone marrow invade the procallus. The fibroblasts produce collagen diners which help connect the broken ends of bones. Phagocytes continue to remove cellular debris. Osteogenic cells develop into chondrioblasts in areas of avascular healthy bone tissue and begin to produce fobrocartilage. Eventually proclaims is transformed into a fubrocartilagenoys callus, A mass of repair tissue that bridges the broken ends of bones.

3. Bony callus formation: In areas with well vasculature, osteogenic cells develop into osteoclasts which begin to produce spongy bone trabeculae. In time the, fibrocartilage is converted to spongy bone and callus is then called as bony callus.

4. Bone remodelling:It is the final stage of fracture repair. Dead fragments of broken bone are gradually resorbed by osteoclasts. Compact bone replaces spongy bone around the periphery of the fracture.

Although bone has a generous blood supply ,healing sometimes takes month. The calcium and phosphorous needed to strength and garden new bone are deposited only gradually and bone cells generally grow and reproduce slowly.