Understanding Bone Structure: The Three Layers of Living Bone

The three layers of living bone are:

1. Endosteum: The innermost layer of bone that lines the medullary cavity and contains osteogenic cells responsible for bone formation and repair.

2. Cortical bone (Compact bone): The dense outer layer of bone that provides strength and rigidity. It consists of closely packed Haversian systems, which are cylindrical structural units containing blood vessels, osteocytes, and collagen fibers.

3. Periosteum: The outermost layer of bone that covers the external surface of the bone except for the joint surfaces. It contains blood vessels, nerves, and osteogenic cells that contribute to bone growth, repair, and remodeling.