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.
The osteocyte’s cell bodies occupy oval or elongated cavities, and the processes occupy the inner space of delicate tunnels that originate in the cavities that contain the osteocytes. These tunnels are called called bone canaliculi. The terminal portion of each canalicule continues with adjacent canalicles. This means that the canalicules communicate with each other and form an extensive net inside the bone matrix.
This net of canalicules is very important for the metabolism of bones, as its extracellular matrix is not permeable to the transit of gases and liquids. For this purpose, nutrients, gases and many molecules travel inside the canaliculi.
The figure is of a small bone specimen prepared to demonstrate the spaces that exist within 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.
What is 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 placed in thionine solution. Medium magnification.