Processing stages of trabecular bone analysis.

<p>Each stage of the processing steps that separate the complete cortical and trabecular bone regions for each specimen, here shown as a sagittal cross-section in a <i>P. troglodytes</i> specimen: (a) the original segmented scan; (b) the outer surface, outlining the external surface of the cortical bone; (c) the inner surface, outlining the internal boundary between the cortical and trabecular bone; (d) the separated cortical bone model (calculated as the outer surface - inner surface); (e) the separated trabecular bone; mask images assigning different grayscale values to (f) the trabecular structure and internal “non-bone” and (g) cortex; (h) the final masked image from which trabecular structure (and cortical structure) can be quantified and the background grid and sampling sphere used to calculate bone volume fraction and the orientation of trabecular bone. Only the head region is shown here but the full bone was processed.