NANOINDENTATION OF BONE - Nanoindentation with Biological Applications - page 185

canal) and generally run parallel to the long-axis of the bone 14 ( Fig. 7-3 ).
Following the replacement of older bone and the deposition of many new
osteons by bone cells over time, remnants of old lamellar structures or
possibly woven bone may continue to exist (and mineralize with time) as
interstitial bone. Imaging of bone using PLM 10 or scanning electron
microscopy (SEM) in backscattered mode (BSE) 15 permits visualization
of osteons, individual lamellae, and different bone types.

Figure 7-3. Circularly polarized light showing the lamellar structure in osteons from
human femoral midshaft. Differing collagen orientations are visualized as “dark” and
“bright” lamellae. Average osteon diameter measures 240 m thick

transverse section). 10,11 Image used with permission from Ascenzi M.G. et al. , (2003). 10

μ m ( × 175; 70 μ

1.3.1. The mineral phase

Bone mineral is composed of extremely impure form of hydroxyapatite,
Ca 10 (PO 4 ) 6 (OH) 2 16,17 which forms nanometer-sized crystals. A substantial
amount of carbonate (CO 3 2- ) is commonly substituted into the apatite
lattice for OH - or PO 4 . 3-16 Additionally, apatite bone mineral contains a