Cells of the periosteum surround the blood vessel and become endosteum. Additional layers are added to the periphery of the osteon outside the endosteum. Outer circumferential lamellae are added to contour the bone surface. Modeling of a long bone Change in shape of a bone as it grows is called modeling . Remodeling of a long bone Skeletally mature bone is constantly turning over by a process called remodeling .
Bone is removed from the surface of trabeculae in spongy bone by the activity of osteoclasts.
New bone is formed by osteoblasts. In compact bone, a cutting cone of osteoclasts resorbs bone. The outer boundary of the resorbed bone is the cement line . Osteoblasts form new bone in the resorption cavity. The blood vessels in the center of the resorption cavity become the new blood vessels in the central canal of the new osteon.