Spongy bone. Coloured scanning electron micrograph (SEM) of freeze-fractured spongy bone tissue. It shows the matrix of collagen and calcium crystals that form the structure of bone tissue. The tissue is part of one of the bony bars (trabeculae) that make up spongy bone. Spongy bone, also called cancellous bone, is found deep inside bones, below a dense shell of hard compact" bone. It consists of a network of hard trabeculae separated by interconnected spaces, giving a mesh-like structure. Although it appears fragile, spongy bone has an important supportive and strengthening role. Magnification: x2000 at 6x7cm size."