Compact bone, light micrograph. Compact bone consists of concentric layers of collagen-containing matrix (lamellae, purple), around Haversian canals, which contain blood and lymph vessels, and nerves. These canals run the length of the bone. The lamellae and canals together form a Haversian system, or osteon. Many systems are arranged in columns running parallel to the long axis of the bone. Osteocytes, the cells which maintain the bony matrix, are housed in small spaces known as lacunae (black dots). Magnification: x150 when printed 10 centimetres wide.