The Haversian system got its name thanks to an English doctor named Clopton Havers (1657-1702), who is known for his original research in the analysis of the microscopic structure of bones and joints. He was the first person to describe Charpy fibers.
The meaning of the term
The Haversian system, or osteons, is the fundamental functional unit of a very compact bone. Osteons are roughly cylindrical structures that typically have a length of several millimeters and a diameter of about 0.2 mm. They are present in many bones of most mammals and some species of birds, reptiles and amphibians.
Compact bone histology with Haversov system
Each system consists of concentric layers or plates of compact bone tissue that surround the central canal. The Gavers channel contains blood supply to the bone. The osteon border is a cement line.
Each Haversian canal is surrounded by a different number (5-20) of concentrically arranged bone matrix plates. Near the surface of the compact bone are parallel to the surface, they are called annular plates.
Some of the osteoblasts develop into osteocytes, each of which lives in its own small space or gap. Osteocytes come into contact with the cytoplasmic processes of their analogues through a network of small transverse channels or tubules. This network provides the exchange of nutrients and metabolic waste.
The collagen fibers in a particular plate are parallel to each other, but the orientation of the collagen fibers in other plates is oblique. The density of collagen fibers is the lowest in the joints between the lamellas, which explains the characteristic microscopic view of the cross section of Havers systems. The space between the osteons is occupied by interstitial plates, which are the remains of osteons.
Haversian systems are connected to each other and periosteum by oblique canals, called Volkman canals or perforating canals.
Drifting osteons
Drifting osteons - a phenomenon that is not fully understood. Drifting osteon is classified as a Haversian system, which passes both in the longitudinal and transverse directions through the cortex. Osteon can “drift” in one direction or change direction several times, leaving the tail of the lamellas behind the advancing Haversian channel.
Investigative Applications
In bioarchaeological studies and in forensic medical examinations, osteons in the bone fragment can be used to determine a person’s gender and age, as well as aspects of taxonomy, diet, health and motor history.
Osteons and their location vary depending on the taxon, so that the genus and species can be differentiated using a bone fragment that cannot be identified otherwise. Nevertheless, there is considerable variability between the various bones of the skeleton, and the features of some osteons of fauna intersect with human osteons. Therefore, the study of Haversian systems is not the main application in the analysis of osteological residues. More research is needed, but osteohistology can have a positive effect on research in bioarchaeology, paleontology, and forensic research.
In recent decades, osteohistological studies of dinosaur fossils have been used to solve a number of problems, such as the frequency of dinosaur growth and whether it was the same for different species, and whether the dinosaurs were warm-blooded or not.