Trabecular bone

Structure

Trabecular bone, also called cancellous bone, is porous bone composed of trabeculated bone tissue. It can be found at the ends of long bones like the femur, where the bone is actually not solid but is full of holes connected by thin rods and plates of bone tissue. The holes (the volume not directly occupied by bone trabecula) is the intertrabecular space, and is occupied by red bone marrow, where all the blood cells are made, as well as fibrous tissue. Even though trabecular bone contains a lot of intertrabecular space, its spatial complexity contributes the maximal strength with minimum mass. It is noted that the form and structure of trabecular bone are organized to optimally resist loads imposed by functional activities, like jumping, running and squatting. And according to Wolff's law, proposed in 1892, the external shape and internal architecture of bone are determined by external stresses acting on it. The internal structure of the trabecular bone firstly undergoes adaptive changes along stress direction and then the external shape of cortical bone undergoes secondary changes. Finally bone structure becomes thicker and denser to resist external loading.