What is the endosteum?

The endosteum is specifically defined as the lining of the medullary cavity, which is the central cavity of long bones that holds bone marrow. This tissue plays a crucial role in bone health and function, as it is involved in the processes of bone growth, repair, and remodeling. The endosteum consists of a thin layer of connective tissue and osteogenic cells that can differentiate into osteoblasts, which are responsible for forming new bone.

Understanding the function of the endosteum within the anatomy of bones is essential for comprehending how bones maintain their integrity and respond to physical activity. It highlights the dynamic nature of bone tissue, contrary to the description of other parts of the bone structure, such as the outer protective layer of bones or the definition of bone cells and long bone shaft features. Each of these other options serves a different role and does not pertain directly to the endosteum's function.