THE ARRANGEMENT OF LAMELLAR BONE IN THE DIAPHYSES – 1
The diaphyses are the strongest component of long bones. Most of them provide the a strong resistance to physical impacts.
The diagram illustrates a small part of a cross-sectioned diaphysis. Notice the following items:
– Four Haversian systems become highlighted in different shades of blue.
– Stacks of flat or sligthly curved bone lamellae fill the spaces left between Haversian systems.
– Haversian canals in the center of each Haversian system contain blood vessels and nerves (nerves not shown in the figure).
– Hollow tunnels called Volkmann’s canals are placed at right angles in relation to the bone long axis and hold branches of blood vessels and nerves that nourish the cells of the Havers systems.
Not shown in drawing that the Haversian systems are superposed one over the next forming parallel columns.
The diagram illustrates a small part of a cross-sectioned diaphysis. Notice the following items:
– Four Haversian systems become highlighted in different shades of blue.
– Stacks of flat or sligthly curved bone lamellae fill the spaces left between Haversian systems.
– Haversian canals in the center of each Haversian system contain blood vessels and nerves (nerves not shown in the figure).
– Hollow tunnels called Volkmann’s canals are placed at right angles in relation to the bone long axis and hold branches of blood vessels and nerves that nourish the cells of the Havers systems.
Not shown in drawing that the Haversian systems are superposed one over the next forming parallel columns.
Nourishment of the bone cells
Small holes that of the bone walls called nutrient foramina allow the passage of blood vessels into bones. The Haversian systems of the diaphysis receive blood from these vessels as well as from branches of vessels that had crossed the whole wall of the bone to deliver blood to the bone marrow.
The nourishment of bone cells that do not stay close to the Haversian canals is done by way of fluid that circulates in the network of the bone canaliculi.
Lamellar bone formed chiefly by Haversian systems and by a few curved parallel lamellae.
