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Periosteum |
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periosteumDense membrane over bones. The outer layer contains nerve fibres and many blood vessels, which supply cells in the bone. The bone-producing cells of the inner layer are most prominent in fetal life and early childhood, when bone formation is at its peak. In adulthood they are less active but vital to continuous bone remodeling. When bone is injured, they multiply profusely to produce new bone. periosteum [‚per·ē′äs·tē·əm] (anatomy) The fibrous membrane enveloping bones, except at joints and the points of tendonous and ligamentous attachment. Periosteum connective tissue in vertebrate animals and man that invests bone (excluding the articular facets, linea aspera, and tuberosities); it joins the bone by means of bundles of collagen fibers and blood vessels. Three layers are distinguished within the periosteum: the external layer (adventitia), which consists of fibrous connective tissue rich in blood vessels; the middle fibroelastic layer, which consists of collagen fibers; and the internal osteoblastic layer, which contains osteoblasts and is usually absent in adult organisms. The periosteum joins bone with surrounding tissues, assures growth of bone tissue (mainly in thickness), and in adult organisms assures regeneration of bone tissue. Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
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