Osteocytes have numerous cell processes but they are not seen in regular routine sections stained with hematoxykin and eosin.
The osteocytes and their processes are located in small cavities within the extracellular matrix called.
The osteocyte’s cell bodies occupy oval or elongated cavities, the lacunae. Their processes occupy the inner space of delicate tunnels that originate in the lacunae that contain the osteocytes. These tunnels are called called bone canaliculi (plural of canaliculus).
The terminal portion of each canalicule connects with neighbour canaliculi. Therefor the canaliculi communicate with each other and form an extensive net inside the bone matrix. This net of canaliculi is very important for the metabolism of bones, as its extracellular matrix is not permeable to the transit of gases and liquids. Nutrients, gases and many molecules are conducted inside the canaliculi.
The figure is of a small bone specimen prepared to demonstrate the lacunae and canaliculi of the bone matrix. This specimen was placed in a solution of the dye Thionine that penetrated into the cavities containing the osteocytes and their processes.
Seen in the image is the dye inside the spaces of the bone. Observe the places inhabited by the osteocyte cell bodies (larger arrows) and by the bone canaliculi occupied by the osteocyte processes (smaller arrows).
Section of a bone specimen that had been placed in thionine solution. Medium magnification.