Light micrograph of human compact bone, which comprises the dense walls of the shafts of long bones. The image shows the organization of compact bone into concentric bony layers (lamellae) arranged around channels containing blood vessels, lymph vessels and nerves. The concentric lamellae and central channel form a Haversian system", a number of which are seen here. The Haversian systems are arranged in columns which run parallel to the long axes of the bone. The small dark spots are spaces (lacunae) which house osteocytes, the cells responsible for the maintenance of the bony matrix. Magnification: x63 at 35mm size."