Haversian canal

Haversian canal is 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 fibers. 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.

Structure

The Haversian canals are approximately 50 μm in diameter. These canals are formed by concentric layers called lamellae. The haversian canals and the lamellae form a complex called an osteon. The space between osteons is occupied by interstitial lamellae, which are the remnants of osteons that were partially removed during the process of bone remodeling. Osteons are connected by Volkmann's canals, which run perpendicular to the Haversian canals.

Function

The Haversian canals provide a channel for the vascular and nerve supply to the osteocytes (the cells of the bony tissue). The canals contain blood vessels that bring nutrients to the bone cells and remove waste products. The canals also contain nerve fibers that sense pain and temperature.

Clinical significance

Damage to the Haversian canals can lead to bone diseases such as osteoporosis. In osteoporosis, the Haversian canals become enlarged, which leads to a decrease in the amount of bone tissue and an increase in the risk of fractures.

See also

• Osteon
• Osteocyte
• Bone remodeling
• Osteoporosis

References

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Haversian canal

• Transverse section of bone
  Transverse section of bone
• Bone cross-section
  Bone cross-section
• Osso por Descalcificação – HE – 40x
  Osso por Descalcificação – HE – 40x
• Osso por Descalcificação2 – HE – 100x
  Osso por Descalcificação2 – HE – 100x