intramembranous bone formation
intramembranous bone formationBone formation that occurs without a prior cartilage model, which contrasts to enchondral ossification.
Embryonic flat bone formation—e.g., skull, maxilla, mandible, pelvis, clavicle, subperiosteal surface of long bone; distraction osteogenesis bone formation; blastem bone (occurs in children following amputations); fracture healing with rigid fixation (e.g., with a compression plate); may occur as a component of healing with intramedullary nailing.
Defects in intramembranous bone formation
Caused by mutation in RUNX2 located on chromosome 6.
Steps of intramembranous bone formation
• Aggregation of undifferentiated mesenchymal cells;
• Osteoblast differentiation;
• Organic matrix deposition.