Periosteum

The periosteum covers the outer surface of bones, except where articular cartilages are present. The periosteum consists of an outer fibrous layer of dense connective tissue and an inner osteogenic layer. The osteogenic layer varies considerably depending on its functional state, reflecting regions of relative inactivity, bone deposition, or bone resorption and remodeling. The periosteum is also well vascularized and innervated. 800x

The periosteum covers the outer surface of bones, except where articular cartilages are present. The periosteum consists of an outer fibrous layer of dense connective tissue and an inner osteogenic layer. The osteogenic layer varies considerably depending on its functional state, reflecting regions of relative inactivity, bone deposition, or bone resorption and remodeling. The periosteum is also well vascularized and innervated. 800x

The fibrous layer of the periosteum also serves at the site of muscle and ligament attachment. Collagen fibers from the muscle tendon and ligament blend with those of the fibrous layer of the periosteum and also extend into the bone matrix as Sharpey’s fibers.

The periosteum covers the outer surface of bones, except where articular cartilages are present. The periosteum consists of an outer fibrous layer of dense connective tissue and an inner osteogenic layer. The osteogenic layer varies considerably depending on its functional state, reflecting regions of relative inactivity, bone deposition, or bone resorption and remodeling. The periosteum is also well vascularized and innervated. 800x

The periosteum covers the outer surface of bones, except where articular cartilages are present. The periosteum consists of an outer fibrous layer of dense connective tissue and an inner osteogenic layer. The osteogenic layer varies considerably depending on its functional state, reflecting regions of relative inactivity, bone deposition, or bone resorption and remodeling. The periosteum is also well vascularized and innervated. 800x

The periosteum covers the outer surface of bones, except where articular cartilages are present. The periosteum consists of an outer fibrous layer of dense connective tissue and an inner osteogenic layer. The osteogenic layer varies considerably depending on its functional state, reflecting regions of relative inactivity, bone deposition, or bone resorption and remodeling. The periosteum is also well vascularized and innervated. 800x

At sites where neither bone deposition nor resorption are occurring, the periosteum is relatively inactive, consisting mostly of osteoprogenitor cells and bone lining cells. Both cell types have a spindle shape and thus difficult to distinguish from each other.

At sites where neither bone deposition nor resorption are occurring, the periosteum is relatively inactive, consisting mostly of osteoprogenitor cells and bone lining cells. Both cell types have a spindle shape and thus difficult to distinguish from each other.

Regions of bone deposition are indicated by the presence of osteoblasts on the surface of existing bone. Osteoblasts secrete osteoid, the organic matrix of bone, which rapidly become mineralized with hydroxyapatite. Bone deposition by the periosteum is an example of appositional bone growth by intramembranous ossification that occurs at sites of bone growth and healing following fracture.

Regions of bone deposition are indicated by the presence of osteoblasts on the surface of existing bone. Osteoblasts secrete osteoid, the organic matrix of bone, which rapidly become mineralized with hydroxyapatite. Bone deposition by the periosteum is an example of appositional bone growth by intramembranous ossification that occurs at sites of bone growth and healing following fracture.

Regions of bone deposition are indicated by the presence of osteoblasts on the surface of existing bone. Osteoblasts secrete osteoid, the organic matrix of bone, which rapidly become mineralized with hydroxyapatite. Bone deposition by the periosteum is an example of appositional bone growth by intramembranous ossification that occurs at sites of bone growth and healing following fracture.

Regions of bone deposition are indicated by the presence of osteoblasts on the surface of existing bone. Osteoblasts secrete osteoid, the organic matrix of bone, which rapidly become mineralized with hydroxyapatite. Bone deposition by the periosteum is an example of appositional bone growth by intramembranous ossification that occurs at sites of bone growth and healing following fracture.

Sites of resorption are indicated by the presence of osteoclasts in the periosteum and Howship’s lacunae on the surface of the bone.

Osteoclasts are derived from monocyte/macrophage stem cells in the bone marrow and arrive in the osteogenic layer via the blood stream. They are not resident cells of the periosteum. Osteoclast activity produces shallow depressions in the bone called Howship’s lacunae.

Osteoclasts are derived from monocyte/macrophage stem cells in the bone marrow and arrive in the osteogenic layer via the blood stream. They are not resident cells of the periosteum. Osteoclast activity produces shallow depressions in the bone called Howship’s lacunae.