The effect of compressive vs. tensile physiological stresses on the stiffness of secondary osteonal bone in white-tailed deer proximal humerus

Cortical remodeling was shown to be affected by the type and magnitude of physiological stress.¶ This study investigated the effect of compression vs. tension loading on the morphology, mineral¶ content and stiffness of secondary osteonal bone in the proximal humerus of white-tailed deer.¶ Thirty cortical bone cubes were prepared from the cranial and caudal aspects and tested in¶ compression along the three principle axes. Next, the cubes were ashed to measure their mineral¶ content. Our results revealed that all samples demonstrated transverse isotropy, but Young’s¶ moduli values and ash content were not significantly different between the regions. There was¶ however a difference in morphology – larger and more medially oriented osteons with relatively¶ smaller central canals in the cranial region. These results reveal that while secondary osteons¶ differ morphemically (size, orientation and porosity) they have the same mineral content and¶ thus their compressive stiffness is not differing.