Bone Structure: Understanding the Layers of Bone

The layers of bone, from the outside to the inside, are:

- Periosteum: The outermost layer, a tough, fibrous membrane that covers and protects the bone. It contains blood vessels and nerves that nourish the bone.

- Compact bone: The dense, hard layer of bone that makes up the majority of the bone's structure. It is composed of tightly packed osteons, which are cylindrical structures containing concentric layers of bone matrix and osteocytes (bone cells).

- Cancellous bone: The inner layer of bone, which is made up of a network of thin, trabecular bone struts. It is less dense than compact bone and contains bone marrow.

- Endosteum: The thin membrane that lines the inner surface of the bone and covers the cancellous bone. It contains blood vessels and nerves that supply the bone marrow.