because next to the foramen a more involved microstructure expected and subsequently noted (Figure 2-15). The 10 regions were aggregated into far (medial B, C, D and lateral B, C, D) and near (medial hole, medial A, lateral hole, and lateral A) regions based on preliminary statistical comparisons.

       Each section was divided in the endoperiosteal direction (through the thickness) into regions according to the mode of strain experienced by the beam; tension, compression or central (low tension and low compression). The tensile and compressive regions measured 0.5 mm in thickness each, and the central region measured 1 mm in thickness.

                             Morphometric Parameters

       Morphometric parameters are intrinsic to the bone and should reflect adaptation to its loading environment in vivo. The morphometric parameters quantified on the Mimages were porosity and osteon density and osteon diameters Detailed explanations on the method for acquiring the images and eventually their quantification can be found in the Appendix; herein, a brief overview of the process is provided.

       Transparencies, on which a 20 Lm x 20  Lm grid was printed, were taped on top of the M-images to count and mark the parameters. The M-images were scanned for the number of Haversian canals, the length Volkmann's canals, and the area of resorption spaces. All these values were put into the following expression to determine porosity.

          %o Porosity =area of voids
                         total area