Osteoporosis is a disease with which bone progressively loses density and becomes fragile, leading to high risk of bone fracture. It is a major health issue in Australia, especially in the elderly population. Early awareness about the disease can help find effective medication and reduce bone fractures with appropriate lifestyle changes. In medical diagnosis, bone mineral density (BMD) measurement is used. However, thereare increased evidences to demonstrate that BMD measurement alone may be insufficient to detect the pathological changes in bone that caused by the disease. Therefore, it is essential to gain a more complete understanding of the bone properties and their effect on osteoporosis.Bone is a hierarchical composite material, which mainly consists of mineral apatite and organic matrix. Previous studies found that osteoporosis or aging could cause microstructural changes in trabecular bones of a proximal femur, the most common site for osteoporosis, and an increased degree of anisotropy was observed in osteoporotic bone properties. To identify the risk of fracture occurrence in the proximal femur as well as to prevent bone fracture, it is important to understand the relationship between bone mineral composition and bone mechanical properties. This thesis thus focused on the characterisation of the mechanical properties and mineral composition of trabecular bone, in order to address several key issues relating to the causes of osteoporosis, including: how does trabecular bone respond to different loading directions? how do bone cysts (which are the implication of pathological scenario due to the trabecular fracture) affect the mechanical properties and the mineral composition of trabeculae ? how does the mineral content affect the mechanical properties of trabeculae across different trabecular types and pathology scenarios ?To answer those questions, trabecular bone samples harvested from bovine and human femoral heads were prepared for testing. Nanoindentation was first used to characterise the mechanical behaviour of trabeculae and atomic force microscopy (AFM) was employed to examine the bone surface tomography. Quantitative backscattered electron imaging (qBEI) was utilized for determining the bone mineral density distribution and the mineral content.ii The results showed that at microscopic scale longitudinal trabeculae were stiffer and harder than transverse trabeculae, because those bones were more highly mineralized.Longitudinal trabeculae also exhibited greater resistance to plastic deformation. The difference in mechanical properties between longitudinal and transverse trabeculae is partially attributed to the difference in their mineral compositions. To further understand the mechanical behaviour of trabeculae, longitudinal and transverse trabeculae were tested in two orthogonal directions. Results showed that both longitudinal and transverse trabeculae had greater elastic modulus in axial direction than in radial direction. Because the axial loading direction is axially aligned with th...