periosteum

n., pl., -te·a (-tē-ə).
The dense fibrous membrane covering the surface of bones except at the joints and serving as an attachment for muscles and tendons.

[New Latin, from Late Latin periosteon, from Greek, from periosteos, around the bone : peri-, peri- + osteon, bone.]

periosteal per'i·os'te·al (-tē-əl) or per'i·os'te·ous (-tē-əs) adj.

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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.

(per′ē-os′tē-um)
n

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.

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.

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