Periosteum: Understanding the Bone's Outer Layer - Definition & Functions

The fibrous layer of a bone is called the periosteum. It is a tough, dense connective tissue that covers the outer surface of bones, except at the joint surfaces. The periosteum is composed of two layers: an outer fibrous layer and an inner cellular layer. The fibrous layer contains collagen fibers and fibroblasts, while the cellular layer contains osteoblasts, osteocytes, and osteoclasts. The periosteum has several functions, including:

- Protecting the bone from damage

- Providing a site for muscle attachment

- Helping to regulate bone growth and repair

- Supplying blood vessels and nerves to the bone