Bone has been described as an engineering masterpiece of tensile, compressive and elastic strength.
         The human skeleton consists of approximately 206 bones and 68 joints. The largest bone is the femur, or thighbone; the smallest is the stapes, a bone inside your ear. As skilled gymnasts clearly demonstrate, bones, muscles, cartilage, and joints can give a healthy body an astonishing degree of flexibility and range of movement. The thumb alone would convince anyone that the architect of our body [whoever that may be to each one of us].
       Bones can also take an incredible pounding. They are constructed in exactly the same way that reinforced concrete is constructed. The steel of reinforced concrete provides the tensile strength, while the cement, sand, and rock provide the compressional strength. However, the compressional strength of bone is greater than that of even the best reinforced concrete. We only wish we could mimic it” said Robert o. Ritchie, a professor of materials science at the University of California, Berkeley, U.S.A.
      Unlike concrete, bone is an essential part of countless living organisms. And it is dynamic. It is able to repair itself, respond to hormones that affect its growth and development, and even play a key role in the manufacture of blood cells. Also, like muscle, it slowly grows stronger as the load on it increases. Hence, athletes have heavier bones than so-called couch potatoes.