Appositional Bone Growth

Process of Appositional Bone Growth

Osteoprogenitor cells differentiate into osteoblasts that add bone matrix under periosteum. Adds successive layers of circumferential lamellae. Trapped osteoblasts become osteocytes. Deeper lamellae recycled and replaced by osteons. Osteoclasts remove matrix at inner surface to enlarge medullary cavity

What are the functions of the Periosteum?

1. Isolate bone from surrounding tissues 2. Route for blood and nervous supply 3. Actively participate in bone growth and repair

Perforating Fibers

Created by osteoblasts in periosteum cellular layer. Strongly connect tendons, ligaments, and joint capsules to bone through periosteum

What are the layers of the Periosteum?

Fibrous outer layer, cellular inner layer.

Endosteum

Incomplete cellular layer lining medullary cavity. Covers spongy bone and lines central canals. Consists of simple layer of osteoprogenitor cells. Where incomplete, osteoclasts and osteoblasts remodel matrix

Appositional Bone Growth

Increases diameter of existing bones, does not form original bones.