Bone Callous Formation

• Bone is living tissue that is continually broken down and rebuilt throughout a persons life.
  
  
• Bone callous formation occurs when a bone is broken and repaired.
  
  
• If a bone is broken it is able to re-grow and bridge the line of fracture with new tissue.
  
  
• The repair mechanism is activated rapidly after injury but the actual full repair can take weeks
  
  
• Once mended a broken bone may take months to regain its former strength.
  

• Blood from damaged vessels near the injury form a clot around the bone, preventing further bleeding.
  
  
• Within days, cells known as fibroblasts start to build up fibrous tissue at the site.
  
  
• This tissue build up is the formation of bone callous.
  
  
• This bridges the gap between the broken bone ends, replacing the blood clot.
  
  
• After about two weeks, spongy bone is deposited on the callous, filling in the gap and keeping the bone ends stable.
  
  
• The damaged blood vessels heal and grow across the break. This bone will gradually become harder as more spongy tissue is deposited.
  
  
• After about three months new compacted bone has replaced the callous.