Figure 5. Phenotypic differences between skull and limb bone.

Low power photomicrographs of (A) skull and (B) limb stained with Toluidine blue for histology and higher power (C) skull and (D) limb bone stained with Alcian Blue 8GX. Regions of acellular bone matrix were masked in the microdensitometer and measured. This ensured that the heavily stained osteocytes did not interfere with the readings. (E) Quantitative assessment by microdensitometry of polysulphated glycosaminoglycan levels in bone matrix stained with Alcian Blue 8GX. (F) Ovariectomy alters osteoblast incorporation into bone matrix as osteocytes in limb bone, but not skull bone, during growth.