The intervertebral foramens of the spinal canal play an important role in the human body, so it is important to know what they consist of, where and how they are formed. Read about this and much more in the article.
Spinal canal
It is made up of intervertebral foramina of the vertebrae, which, in turn, are formed by bodies, arches, and ligaments. The diameter of the channel is much larger in the area of such departments as the lumbar and cervical, as they are more mobile compared to the thoracic.
The spinal canal has a very important function: it is the location of the spinal cord. The channel formed by the vertebrae reliably protects its delicate tissue. The central nervous system is formed from the spinal cord and brain, the purpose of which is to regulate all functions in the human body. Therefore, in order to ensure normal functioning of the spinal cord, it is important to maintain the integrity and anatomical structure of the canal.
What is an intervertebral foramen?
This is a narrow, funnel-shaped opening through which nerve roots and veins exit the spinal canal. Arteries, on the contrary, enter it,supplying nerve structures with blood. Where are the intervertebral foramen located? Their location is the lateral sections of the spinal column, that is, between every two vertebrae that form a pair, one on each side. Simply put, the body and bone processes, when connecting the vertebrae, form holes, which are called intervertebral. The nerves that exit through these openings are called the spinal nerves.
As for the functional relationship, the size of the holes between the vertebrae is not as important as their shape, as well as the size of the canal through which the spinal nerves pass. The parameters of this channel are affected by:
- Size of the lateral recess in the spinal canal.
- The shape and size of the processes of the joints.
- Yellow Bundle (her condition).
- The edge of the body of the vertebra itself and the disc between the vertebrae.
Where do they form?
Intervertebral foramina are formed by the upper and lower vertebral notches, which appear in the process of joining the vertebrae. The restriction in front occurs due to the intervertebral discs and vertebral bodies located in the neighborhood. Above and below, the restriction for the holes are the legs of the arches, and behind - the yellow ligaments, as well as the joints that have grown over the arches. Thanks to the anterior and posterior joints, a mobile intervertebral joint is formed. When the intervertebral foramen is narrowed, it means that there has been a change in one of the joints, which can lead to nerve compression.
There are only 23 pairs of holes between the vertebrae along the entire length of the spine. They increase in size from top to bottom. Cervical openings between the vertebrae - four millimeters each, in the region of the fifth lumbar vertebra - 10, 2.
What are vertebrae?
It is impossible to consider the intervertebral foramen separately from the vertebrae, so it is important to know what they are. The vertebrae are the bones that form the spinal column. The vertebrae have a cylindrical body, which is called their front part. The main support load falls on him. This is due to the fact that when the weight of a person is distributed on the spine, the bulk of it goes to the front. Behind the body is a bow, which has the shape of a semicircle, from which processes extend in the amount of seven pieces. The shackle is attached to the body of the vertebra by legs.
By their structure, the vertebrae are spongy bones, the top layer of which is bone beams, separated by cells. They contain red bone marrow. Thanks to the body and the arch, the intervertebral foramen of the vertebra is formed. With respect to the spinal column, their location is determined strictly symmetrically one above the other, resulting in the formation of the spinal canal, which is the location of the spinal cord, nerve roots, blood vessels, and fatty tissue in it.
Connection of the vertebrae and their bodies
To understand how intervertebral foramina are formed,it is important to know how the vertebrae are connected. This process occurs with the help of synchondroses, that is, intervertebral discs. The columns of the vertebrae connected by them, or rather their bodies, are fastened with the help of two longitudinal ligaments that run along the midline from the front and back sides. The joints of all vertebrae provide the spine with high mechanical strength, mobility, and flexibility.
Intervertebral discs
These are dense formations that have a rounded shape. Their location is the space formed by the connection of adjacent vertebrae. The structure of the disk is very complex. The nucleus pulposus with its elastic properties is given a place in the center. It is a vertical load absorber. The fibrous ring in many layers is located around the nucleus. Thanks to the ring, it is held in the center and does not allow the vertebrae to move. The intervertebral discs of adults do not have blood vessels, and their cartilage is supplied with food by the vessels of the vertebral bodies. It is for this reason that many drugs cannot get into the cartilaginous tissue of the discs, which greatly complicates the treatment of many diseases of the spine.
Layers and fibers of the annulus have the ability to cross in several planes. Normally, without any pathologies, the formation of the ring occurs with fibers of great strength. But if disc disease occurs, for example, osteochondrosis, then the fibers of the fibrous ring are replaced by scar tissue. In turn, the tissue fibers do not have such elasticity and strength, as a result of which the disc weakens. If the intradiscal pressure rises, the annulus may rupture.
During life, the structure of discs changes, as well as their size. At the age of 13 years, the growth and development of all tissues in width and height occurs. After some time, the process slows down and stops completely in adults. Before adolescence, the discs have blood vessels, but by the age of 25 they disappear. Adults don't have them.
Bundles
The posterior longitudinal and yellow ligaments are considered the most significant. The first performs the function of a strand, with its help all bodies are connected from behind. The yellow ligament, which is so called due to the pigment, has a different purpose: thanks to it, all the arcs are connected. Ligaments perform a specific function. If the intervertebral discs and joints are destroyed, the task of the ligaments is to compensate for the instability, which in this case is the pathological mobility of the joints.
The result of the work of the ligaments is their hypertrophy, and this leads to the fact that the lumen in the spinal canal decreases. Therefore, the formation of bone outgrowths or hernias, even the smallest in size, leads to narrowing of the intervertebral foramina, which causes compression of the spinal cord and roots.
What is stenosis?
This disease is, as a rule, a chronic form, in which the pathological process progresses. It is characterized by the fact that the central canal and the intervertebral foramen (the photo is presented for viewing) narrow. This is due to the fact that bone andcartilage grows. Pathology is observed in diseases such as osteoarthritis, spondylosis and others.
Stenosis of the spinal canal is a common pathology that affects older people who have crossed the 60-year threshold in 21% of cases. But it is noteworthy that only 30% of patients showed symptoms of the disease. Usually it is diagnosed during examination for a completely different reason. In most cases, the narrowing in the spinal canal occurs in the lumbar region.
Stenosis is diagnosed when, after a complete examination, tests show that the distance between the posterior surface of the vertebral body and the base of the spinous process is less than 12 mm. Such measurements characterize the narrowing, in which there is a decrease in the cross section of the central channel. There is another type of stenosis - lateral. It is characterized by narrowing of the openings between the vertebrae. Such a diagnosis is established if the holes are reduced to four millimeters.
