Trabecular bone occurs in the expanded head of the long bones. It also makes up most of the bone tissue in the vertebrae. It has a light, honeycomb structure in which a three-dimensional network of trabeculae act as struts. It is sometimes called spongy bone.
This type of structure is optimised for strength and lightness. The trabeculae are oriented so that they can take up the stresses in the bone. Figure 4 shows the head of the femur and you can see how the trabeculae are arranged to give the bone strength exactly where it is needed. The spaces between them contain blood vessels and bone marrow.