The endosteum is a thin layer of connective tissue which lines the surface of the bony tissue that forms the medullary cavity of long bones. The outer surface of a bone is lined by a thin layer of connective tissue that is very similar in morphology and function to endosteum. It is called "periosteum".
- Netter, p. 171
- Netter, Frank H. (1987), Musculoskeletal system: anatomy, physiology, and metabolic disorders, Summit, New Jersey: Ciba-Geigy Corporation