Covering, Support, and Movement of the Body
Chemical Composition of Bone
Bone contains both organic and inorganic substances.
include bone cells and osteoid. Its
are mineral salts.
Only a few cells thick, trabeculae contain irregularly arranged
lamellae and osteocytes interconnected by canaliculi. No oste-
ons are present. Nutrients reach the osteocytes of spongy bone
by diﬀusing through the canaliculi from capillaries in the en-
dosteum surrounding the trabeculae.
Endosteum lining bony canals
and covering trabeculae
Perforating (Sharpey’s) fibers
Periosteal blood vessel
in a lacuna
Lacuna (with osteocyte)
Microscopic anatomy of compact bone.
Diagram of a pie-shaped segment
of compact bone.
Close-up of a portion of one osteon. Note the position of osteocytes in
SEM (left) of cross-sectional view of an osteon (410
). Light photomicrograph
(right) of a cross-sectional view of an osteon (410