^BCancellous bone. ^bColoured^B ^bscanning electron micrograph (SEM) of a section through developing cancellous (spongy) bone from the foot of a human foetus. This type of bone tissue is found deep inside bones, below a dense shell of hard "compact" bone. It consists of a network of hard ^Itrabeculae^i separated by interconnected spaces (^Icancelli^i) filled with bone marrow. Bone marrow is a living tissue which manufactures blood cells. Cancellous bone has an important supportive and strengthening role. Magnification unknown.