Compare Compact and Spongy Bone
It is found in the long bones and it is surrounded by compact bone. The term spongy comes from the fact that it is a highly vascularized and porous tissue. Trabeculae are spaces created in the tissue by thin areas of osteoblast cells. As a result, trabecular bone has about 10 times the surface area of compact bone. It also makes up about 20% of a human skeleton. Spongy bone is home to the bone marrow and hematopoietic stem cells that differentiate into red blood cells, white blood cells and platelets.
Spongy bone consists of plates (trabeculae) and bars of bone adjacent to small, irregular cavities that contain red bone marrow. The canaliculi connect to the adjacent cavities, instead of a central haversian canal, to receive their blood supply. It may appear that the trabeculae are arranged in a haphazard manner, but they are organized to provide maximum strength similar to braces that are used to support a building. The trabeculae of spongy bone follow the lines of stress and can realign if the direction of stress changes.