periosteum

Pronunciation: per′ē-os′tē-ŭm, -ă

Definition: The thick, fibrous membrane covering the entire surface of a bone except its articular cartilage and the areas where it attaches to tendons and ligaments. In young bones, it consists of two layers: an inner cellular layer that is osteogenic, forming new bone tissue, and an outer fibrous connective tissue layer conveying the blood vessels and nerves supplying the bone; in older bones, the osteogenic layer is reduced.

Synonym(s): periost

[Mod. L. fr. G. periosteon, ntr. of adj. periosteos, around the bones, fr. peri, around, + osteon, bone]

See Also: perichondral bone

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