What is the term for the outer protective layer of a bone?

The outer protective layer of a bone is known as the periosteum. This dense connective tissue wraps around the exterior of bones, serving several critical functions. It provides a surface for the attachment of muscles and tendons, contributing to the mechanical strength of the bone. Additionally, the periosteum contains blood vessels and nerves, which are essential for bone health and vitality. It plays an important role in the growth and repair of bones as well.

The other terms mentioned refer to different structures associated with bone. The endosteum, for example, is a thin membrane lining the inner surfaces of the bone, particularly the cavities and canals, while the epiphysis is the end part of a long bone, which is initially separated from the main bone shaft by a growth plate. An osteon refers to the structural unit of compact bone, consisting of concentric layers of matrix and cells surrounding a central canal. Each of these components serves distinct roles in the overall anatomy and physiology of the skeletal system, but the periosteum specifically is recognized for its role as the protective outer layer.