The dense fibrous membrane that covers the outer surface of bones except at joint surfaces. It contains blood vessels, nerves, and bone-forming cells (osteoblasts) essential for bone growth, repair, and nutrition.
From Greek 'peri' (around) and 'osteon' (bone), literally meaning 'around the bone.' The term was coined in anatomical studies to describe this vital bone covering that ancient physicians recognized as essential for bone health.
When you get a bone bruise or 'bone deep' pain, you're actually feeling injury to the periosteum - the bone itself has no pain receptors! This membrane is also why broken bones can heal themselves, as it contains the stem cells that become new bone tissue.
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