In mature compact bone most of the individual lamellae form concentric rings around larger longitudinal canals (approx. 50 µm in diameter) within the bone tissue. These canals are called haversian canals. Haversian canals typically run parallel to the surface and along the long axis of the bone. The canals and the surrounding lamellae (8-15) are called a haversian system or an osteon. A haversian canal generally contains one or two capillaries and nerve fibres.