INFLUENCE OF AGEING ON BONE MINERAL PROFILE AND MECHANICAL STRENGTH

Bone is a structurally complex and mechanically significant material that plays a central role in the human skeletal system. Its hierarchical organization and composition are optimized to meet diverse functional demands, ranging from providing structural support and facilitating locomotion to protecting soft tissues and serving as a mineral reservoir. Mechanical testing of bone, particularly cortical bone, is essential for understanding its load-bearing properties and functional performance under different physiological and pathological conditions. Cortical bone, which constitutes the dense outer walls of bones and the diaphysis of long bones, is characterized by low porosity and microscopic channels. It is distinct from trabecular bone, which is more porous and located in regions requiring energy absorption and metabolic activity. At the ultra-structural level, both cortical and trabecular bones are composed of approximately 65% mineral phase, largely hydroxyapatite crystals, and 35% organic matrix, primarily type I collagen. This composite nature provides bone with its unique combination of strength, stiffness, and resilience. By integrating mineralized components with collagen fibers, bone achieves a balance between rigidity and toughness, ensuring its capacity to withstand complex mechanical loads. Understanding the mechanical behavior of bone, especially cortical bone, not only contributes to biomedical research and orthopedic applications but also aids in developing improved biomaterials, prosthetics, and treatments for bone-related disorders. This study provides an overview of the mechanical functions, hierarchical organization, and compositional attributes of cortical bone, emphasizing the significance of mechanical testing in advancing knowledge of bone mechanics