This paper presents a microstructural analysis of an idealized cortical bone cross-section using finite element analysis. The purpose of the model is to examine the influence that the cement line has in reducing Haversian canal wall stresses when microcracks are present. The cement line modulus was varied between 40%-80% of the osteonal modulus. Three microcrack geometries were considered: a radial crack emanating from the Haversian canal; an interface crack between the cement layer and the interstitial bone; and a radial crack running from interstitial bone into the cement layer. The data show that larger cement line moduli reduce stresses on the Haversian canal wall. The data also show that the stress concentration on the Havesian canal wall is higher than the concentration at the crack tip for any of the microcrack geometries considered. The introduction of a microcrack to a bone section increases the stress concentration on the Haversian canal walls.