Microscopy Section Analyses Setup

       Two of the fatigued beams were analyzed with respect to morphometric and damage parameters describe subsequently. A total of three sections per beam were analyzed: one through the foramen and one through the drilled hole, and one through the control hole. The morphometric parameters included microstructural characteristics intrinsic to the bone. The damage parameters included quantitative measures of damage.

       Images of the entire bone sections were taken, and put together in a sort of mosaic, denoted as an M-image. The M-image is a paper banner composed of three printouts and used as a map to locate important features and for organization. The images that comprised the M-image were taken using a brightfield microscope (Olympus BX-60 Melville, N.Y.), a digital color camera (Cohu CCD RGB), and a frame (Integral Technologies, Flashpoint 128). The microscope was used with a 4X objective, due to the magnification of the camera the total magnification was 142.5X. Using a square grid as a guide, images of each bone section were taken every 1 mm. A complete M-image was comprised of 30 images, or 2 rows of 15 images. These images were cropped to square millimeters and put together using Matlab. The M-image was used extensively: morphometric parameters were measured with it and it served as a fixed frame of reference where the location of every single crack was noted.

       Initially, each section was divided in the mediolateral direction into 10 regions; The 10 regions were identified considering their proximity to the hole. (medial D, medial C, medial B, medial A, medial hole, lateral hole, lateral A, lateral B, lateral C, and lateral D). Each region measured 1 mm in length and the height of the beam (approximately 2mm), except for the two regions next to the holes (the near regions) which measure 0.50 mm in length (Figure 2-15). The reason why the near regions are shorter in length is