👉 The term "endosteum" refers to the outermost layer of bone, which is composed primarily of osteoblasts (bone-forming cells) and osteocytes (bone-closing cells). These cells are responsible for producing new bone tissue through a process called ossification. The endosteum is also known as the periosteum and is located between the bones in the human body. The endosteum can be divided into three main regions: the outer, middle, and inner end