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Haversian canals [i] (sometimes canals of Havers, osteonic canals or central canals) are a series of microscopic tubes in the outermost region of bone called cortical bone. They allow blood vessels and nerves to travel through them to supply the osteocytes .
Each osteon consists of concentric layers, or lamellae, of compact bone tissue that surround a central canal, the Haversian canal. The Haversian canal contains the bone's blood supplies. The boundary of an osteon is the cement line. Each Haversian canal is surrounded by varying number (5-20) of concentrically arranged lamellae of bone matrix.
Havers' thesis. Clopton Havers (24 February 1657 – April 1702) was an English physician who did pioneering research on the microstructure of bone. He is believed to have been the first person to observe and almost certainly the first to describe what are now called Haversian canals and Sharpey's fibres.
It consists of multiple microscopic columns, each called an osteon or Haversian system. Each column is multiple layers of osteoblasts and osteocytes around a central canal called the osteonic canal. Volkmann's canals at right angles connect the osteons together. The columns are metabolically active, and as bone is reabsorbed and created the ...
In bovine tibia diameter of canaliculi was found to vary from 155 to 844 nm (average 426 nm). [2] In mice humeri it varies from 80 to 710 nm (average 259 nm), while diameter of osteocytic processes varies from 50 to 410 nm (average 104 nm).
All the ceramic pottery sherds found at the site dated to the Late Woodland period Napier Phase, circa 900 CE. The lithic debris found at the site was all locally available quartz and Ridge and Valley chert from the northwestern Georgia area. A small greenstone celt was found during a posthole test on the summit of Mound A. [1]
Volkmann's canals, also known as perforating holes or channels, are anatomic arrangements in cortical bones that allow blood vessels to enter the bones from periosteum. They interconnect the Haversian canals (running inside osteons ) with each other and the periosteum.
Fibrolamellar bone is fairly common in young crocodilians and sometimes found in adults. [68] [69] Haversian bone has been found in turtles, crocodilians and tortoises, [70] but is often absent in small birds, bats, shrews and rodents. [69] Nevertheless, de Ricqlès persevered with studies of the bone structure of dinosaurs and archosaurs.