Final answer:
A bone is covered externally with a sheath called periosteum, whereas the internal surface is lined with endosteum.
Step-by-step explanation:
The outer surface of a bone is covered by a fibrous sheath called the periosteum, while the inner surface is lined with the endosteum, which facilitates bone growth, repair, and remodeling.
The periosteum is a fibrous membrane that contains blood vessels, nerves, and lymphatic vessels which nourish compact bone. It also serves as an attachment point for tendons and ligaments. Except in regions of articulations where epiphyses meet other bones to form joints, the periosteum covers the entire outer surface of the bone.
The hollow part within bones like the long bones' diaphysis is called the medullary cavity and is lined with the endosteum, a delicate membranous lining responsible for bone growth, repair, and remodeling. The endosteum also lines the internal cavities of spongy bone found within the epiphysis of long bones.