Bone is formed from minerals, usually, calcium salts, effective together through the way of sturdy collagen fibers. Our bones have a thick, difficult outer shell (called cortical or compact bone) which is barring for troubles considered on x-rays. Inside this, there's a softer, spongy mesh of bone (trabecular bone) that features a honeycomb-like structure. Bone may be a living, filled with living tissue that's persistently renewing itself.