Coloured SEM of bone marrow from a fractured rib. Bone marrow (orange) lies in the spaces of the spongy (cancellous) bone within the centre of the bone. Credit: Steve Gschmeissner/Science Photo Library
Compact bone, from human femur. Bone is made up of two types of tissue: the compact bone forms a shell around the spongy cancellous bone that makes up the marrow space in the centre. Compact bone provides strength and rigidity and is solid in appearance. It is composed of a layered matrix of organic substances and inorganic salts that form around an intricate network of vasculature called Haversian canals. Credit: Ivor Mason, KCL, Wellcome Images.