Structural differences in the cortical bone of Turkey tibia

Abstract

Different regions namely anterior, posterior, medial and lateral, of the cortical bone in six sections in the diaphysis from proximal to the distal end of a Turkey tibia were evaluated for structural differences. The predominant feature, Haversian canals showed high area fraction (can be viewed as high porosity) in the posterior region as compared to the anterior region and this difference is attributed to the high compressive and tensile stress states in the respective regions. With increasing size, the Haversian canals deviated from circular shapes in cross section. The distance from the lacunae to the center of the Haversian canal showed an increase with the size of the canals. However, the canal to lacunae-canal distance ratio is independent of the anterior and posterior regions. It was found that majority of the lacunae are placed at a distance of about 2.5 to 3 times the Haversian canal radius. At the ultrastructural level, periodic banding of the collagen fibers showed a bimodal banding in the anterior region while only one finer banding distribution in the posterior region and could probably the result of the different stress states in the two regions. The Haversian canals in the three dimensional reconstruction showed branching, twisted canals and Haversian space and resemble Cohen and Harris model. Differences in stress in different regions cause structural changes in bone.