Figure 1. Osteocyte and the hierarchic organization of bone.
(A) X-ray image of a murine femur and (B) rat femur stained with von Kossa and McNeal to show the bone stained in black and bone marrow, stained in blue, showing the bone structure. (C) Image of dry human showing osteocytes and their canaliculi (in black). (D) Scanning electron microscopy of acid etched murine vertebral bone the cellular organization of osteocytes within bone with their projections reaching other osteocytes and cells on the bone marrow. (E) TRAP-stained osteoclasts (in red) on rat bone sections stained with TRAPase and toluidine blue and (F) osteoblasts present on bone surfaces covered by osteoid in rat bone sections stained with von Kossa and McNeal, showing the close proximity of osteocytes (grey arrows) to osteoblasts (red arrows) and osteoclasts (yellow arrows) on the bone surface. (G) Early osteocyte being embedded in bone matrix that is partially (left) and completely (right) mineralized (10,000 x). The boxes in panels B and F delineate the areas enlarged in panels C and F, respectively. Pictures for panels B and F were contributed by Keith Condon, Indiana University School of Medicine, Indianapolis, IN, USA. Picture for panel G was provided by Stephen B. Doty, Hospital for Special Surgery, New York, NY, USA.