periosteum

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A glistening-white, double-layered membrane of connective tissue covering the outer surface of bone. It is richly supplied with nerve fibres, lymph vessels, and blood vessels. The periosteum may become inflamed (a painful condition known as periostitis), when the insertion point of a tendon is severely strained, stretched or torn. This overuse injury commonly occurs when exercisers run on hard roads, or when they change technique or equipment. Periostitis is much more common in poorly conditioned exercisers than in fit athletes. See also shin splints.

A glistening-white, double-layered membrane of connective tissue covering the outer surface of bone. It is composed of an outer fibrous layer of dense, irregular connective tissue, and an inner layer of bone-forming cells called osteoblasts. The periosteum is richly supplied with nerve fibres, lymph vessels, and blood vessels. It is secured to the underlying bone by strong fibres (Sharpey's fibres), which are exceptionally dense where the periosteum provides anchoring points for tendons and ligaments.

A specialized connective tissue covering all bones of the body, and possessing bone-forming potentialities. It is made up of an outer tough fibrous layer and a deeper more succulent osteogenic layer. Periosteum also serves as a point of attachment for certain muscles, tendons and ligaments. The connective tissues fuse with the fibrous layers of periosteum.

The layer of connective tissue that varies considerably in thickness in the different areas of bone. It is thick over the surfaces that do not serve as areas of muscle attachment, especially on surfaces that are covered only by skin and subcutaneous tissue. In these areas the periosteum connects loosely with the bone itself and is easily lifted from it. Muscles are attached to bones directly, or they end on the periosteum. When muscles or tendons are attached to the bone, connective tissue extends into the bone as Sharpey’s fibers. In such areas a periosteum may be lacking. When muscles are attached to the periosteum and thus are indirectly attached to the bone, the periosteum is relatively thin but is strongly fixed to the bone. The periosteum consists of two layers: an outer layer, which is rich in blood vessels and nerves and shows a dense arrangement of collagenous fibers, and an inner layer, the cambium, in which the fibers are loosely arranged, the cells numerous, and the blood vessels relatively sparse. During active growth, this layer of osteoblasts covers the periosteal surface of the bone. In the quiescent state in the adult, the periosteum primarily provides support. However, the inner layer retains its osteogenetic potencies and in fractures is activated to form osteoblasts and new bone.

Periosteum
compact spongy bone
Meninges of the CNS
Code	TH H2.00.03.7.00018

Periosteum is a membrane that lines the outer surface of all bones,^[1] except at the joints of long bones.^[2] Endosteum lines the inner surface of all bones.

Periosteum consists of dense irregular connective tissue. Periosteum is divided into an outer "fibrous layer" and inner "cambium layer" (or "osteogenic layer"). The fibrous layer contains fibroblasts, while the cambium layer contains progenitor cells that develop into osteoblasts. These osteoblasts are responsible for increasing the width of a long bone^[3] and the overall size of the other bone types. After a bone fracture the progenitor cells develop into osteoblasts and chondroblasts, which are essential to the healing process.

As opposed to osseous tissue, periosteum has nociceptive nerve endings, making it very sensitive to manipulation. It also provides nourishment by providing the blood supply. Periosteum is attached to bone by strong collagenous fibers called Sharpey's fibres, which extend to the outer circumferential and interstitial lamellae. It also provides an attachment for muscles and tendons.

Periosteum that covers the outer surface of the bones of the skull is known as "pericranium" except when in reference to the layers of the scalp.

Contents 1 Etymology 2 Additional images 3 External links 4 See also 5 References 6 Bibliography

Etymology

The word Periosteum is derived from the Greek Peri- meaning "surrounding" and -osteon, meaning "bone". The Peri refers to the fact that the Periosteum is the outermost layer of long bones, surrounding other inner layers.^[4]

Additional images

• 

  Diagrammatic section of head.

External links

1. http://www.innerbody.com/image_skel09/skel01.html

2. http://encycl.opentopia.com/term/Periosteum

See also

• Periostitis

References

1. ^ Netter, Frank H. (1987). Musculoskeletal system: anatomy, physiology, and metabolic disorders. Summit, New Jersey: Ciba-Geigy Corporation ISBN 0-914168-88-6, p.170
2. ^ At the joints of long bones the bone's outer surface is lined with "articular cartilage", a type of hyaline cartilage.
3. ^ The length of a long bone is controlled by the epiphyseal plate.
4. ^ http://www.etymonline.com/index.php?term=peri-

Bibliography

• Brighton, Carl T. and Robert M. Hunt (1997), "Early histologic and ultrastructural changes in microvessels of periosteal callus", Journal of Orthopaedic Trauma, 11 (4): 244-253

v t e Musculoskeletal system · connective tissue: bone and cartilage (TA A02.0, TH H3.01, GA 2.86–95) Cartilage perichondrium · fibrocartilage callus · metaphysis cells (chondroblast · chondrocyte) types (hyaline · elastic · fibrous) Bone Ossification intramembranous · endochondral Cycle osteoblast · osteoid · osteocyte · osteoclast Types cancellous · cortical Regions subchondral bone · epiphysis · epiphyseal plate/metaphysis · diaphysis · Condyle · Epicondyle Structure osteon / Haversian system · Haversian canals · Volkmann's canals · connective tissue (endosteum · periosteum) · Sharpey's fibres · enthesis · lacunae · canaliculi · trabeculae · medullary cavity · bone marrow Shapes long · short · flat · irregular · sesamoid M: BON/CAR anat(c/f/k/f, u, t/p, l)/phys/devp/cell noco/cong/tumr, sysi/epon, injr proc, drug(M5)

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