From Greek periosteon 'around the bone,' the nerve-rich membrane that sheathes bones and enables their repair.
The dense layer of connective tissue that covers the outer surface of bones, providing attachment for tendons and ligaments.
From Greek periosteon 'the membrane around the bone,' from peri- 'around' + osteon 'bone.' The periosteum is rich in blood vessels and nerves, which is why a blow to the shin (where the bone is close to the surface) is so painful. Key roots: *h₃ost- (Proto-Indo-European: "bone").