Haversian canal

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Haversian canal
Diagram of compact bone from a transverse section of a typical long bone's cortex.
Identifiers
FMA224787
Anatomical terminology
Diagram of a typical long bone showing both cortical (compact) and cancellous (spongy) bone.

Haversian canals

cortical bone. They allow blood vessels and nerves to travel through them to supply the osteocytes
.

Structure

Each Haversian canal generally contains one or two

bone tissue its strength. Active transport is used to move most substances between the blood vessels and the osteocytes.[1]

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.

Clinical significance

Fracture

Blood vessels in the Haversian canals are likely to be damaged by bone fracture.[2] This can cause haematoma.[2]

Rheumatoid arthritis

Haversian canals may be wider in patients with rheumatoid arthritis.[3] They are also more likely to contain osteoclasts that break down bone structure.[3] These differences are studied with light microscopy.[3]

History

Haversian canals were first described (and probably discovered) by British physician Clopton Havers, after whom they are named.[4] He described them in his 1691 work Osteologica Nova.[5]

In different animals

Human bones are densely vascularized as in many other mammals. Even though some authors tried to identify a correlation between

ichthyosaurs, phytosaurs, basal stem-mammals (e.g. Ophiacodon), Limnoscelis, and temnospondyls. When endosteal Haversian systems are considered, the phylogenetic distribution becomes even broader.[6]

Notes

References

External links

Additional images

  • Bone by decalcification (40x): Volkmann's canal Haversian canal Blood vessel
    Bone by decalcification (40x):
    1. Volkmann's canal
    2. Haversian canal
    3. Blood vessel
  • Bone by decalcification (100x): Volkmann's canal Haversian canal Lacuna Lamella
    Bone by decalcification (100x):
    1. Volkmann's canal
    2. Haversian canal
    3. Lacuna
    4. Lamella