Macrophoto of a cross-section through normal human cancellous (spongy) bone from the upper arm. Bone tissue can be either compact or cancellous; both forms are usually present in any particular bone of the body. Cancellous bone, usually found in the interior of bone, is characterised by tissue arranged as an open honeycomb. This honeycomb con- sists of a network of trabeculae (bars) and spicules separated by large spaces. The spaces within cancellous bone contain bone marrow, a blood forming substance. Spongy bone often appears fragile but does have a supportive and strengthen- ing role. Magnification: x3 at 6x6cm size.