<Tr> <Td_colspan="2"> Diagram of compact bone from a transverse section of a typical long bone's cortex . </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> Haversian canals (sometimes canals of Havers, named after British physician Clopton Havers) are a series of microscopic tubes in the outermost region of bone called cortical bone that allow blood vessels and nerves to travel through them . Each haversian canal generally contains one or two capillaries and nerve fibres . The channels are formed by concentric layers called lamellae . The haversian canals surround blood vessels and nerve cells throughout bones and communicate with bone cells (contained in spaces within the dense bone matrix called lacunae) through connections called canaliculi . This unique arrangement is conducive to mineral salt deposits and storage which gives bone tissue its strength . </P> <P> 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 are contained within osteons, which are typically arranged along the long axis of the bone in parallel to the surface . The canals and the surrounding lamellae (8 - 15) form the functional unit, called a haversian system or osteon . </P>

Osteons central canals and lamellae may be observed in