The other bone tissue type is the trabecular bone (Figure ) otherwise known as spongy or cancellous bone. Generally spongy bone exists at the end of the long bone (protected by a shell of a cortical bone named periosteum) and bone cavity or in the middle of the laminar bones. It can be divided into four forms based on the structure of trabecular networks: (i) a mesh structure formed by small rods; (ii) a structure where part of those rods is replaced by small plates; (iii) a structure where somewhat aligned plates, can be few millimeters long and lastly (iv) trabecular tissue formed entirely out of plates. In trabecular bone, lamellae are aligned with the long axis of the trabeculae, which form a network of rods and plates with a thickness ranging from 100 to 300 μm and length of 1mm. The distances between individual trabeculae range from 0.5 to 1.5 mm or more 8 .