Bone micro architecture

Bone is a living composite material (70% mineral) which moves, supports, and protects organs of the body, produces red and white blood cells, and stores minerals. Bone is a connective tissue. 

Two types of bone can be distinguished:

Compact bone (cortical bone) is the rigid part of the bone which is usually found on bone surfaces. Its mechanical

    role is to support mechanical stresses, such as the weight of the body (quite similar to the foundation of a house).

Trabecular bone (cancellous bone) is a kind of  honeycomb-like three-dimensional structure which is contained

    within the compact bone structure. The mechanical role of trabecular bone is to absorb shock and transmit the

    shock energy to the compact bone.

With osteoporosis, compact and trabecular bone both are impacted, but not to the same degree. The trabecular structure is affected 4 times more than cortical bone due to a more rapid remodeling process, thereby leading to the thinning of bone and declining number of trabeculae.

These alterations decrease the absorption shock capacity of the trabecular bone, leading to increased mechanical fragility and, consequently, to increased fracture risk.

The cortical bone becomes more porous and thinner, further contributing to increased fracture risk.