The complex structure of the human spine is necessary to maintain balance when walking and cushioning each movement. Therefore, it consists of individual vertebrae, movably connected to each other and separated by intervertebral discs. But not all parts of the spine have such a structure. Sacral vertebrae are divided only in children and adolescents. By about 18 years old, they grow together, forming a solid bone. It is called the sacrum, and it has a special structure. This department is isolated separately, but sometimes combined with lumbar and coccygeal, as they perform similar functions.
Spinal anatomy
The human spine is a complex system consisting of individual vertebrae, movably connected to each other using joints of a special structure and many ligaments. To cushion movements when walking between the vertebrae are soft disks. They protect the mentioned elements from destruction, and the brain from concussion. This structure provides mobility of a person, the ability to perform inclinations, turns, maintain balance when walking.
The danger of such a complex structure is that within each vertebra passes the spinal canal, many nerves and blood vessels. Therefore, it is so important to maintain the spine in the correct position and protect it from injury. The most common injuries are dislocations or displacement of the vertebrae, disc herniation, tissue deformation.
In the structure of the spine, five departments are distinguished:
- cervical;
- thoracic;
- lumbar;
- sacral;
- coccygeal.
But because of the structural features of the lower sections, they are sometimes combined. When they say "vertebrae of the lumbosacral spine", they often mean the sacrum, coccyx, and lower back. After all, they perform similar functions, and even their diseases and injuries are similar.
Sacral spine
This is a special part of the human ridge. This department consists of five vertebrae. They have a complex structure and perform very important functions. The sacral vertebrae are connected movably only up to 14-15 years. After this age, they begin to gradually grow together. This process begins from the bottom, at the junction with the coccyx. Finally, the sacrum turns into a single bone by the age of 25. The sacral and coccygeal vertebrae in an adult are triangles facing downward. This is the base of the spine, providing its connection with the pelvis and lower limbs.
The structure of the sacrum
This department is the foundation of the human spine. Therefore, the structure of the sacral vertebrae is slightly different from the rest. They have underdeveloped ribs and fused transverse processes. And in the upper part there are special ear-shaped surfaces needed to connect with the pelvic bones. This joint is called the sacroiliac joint. Due to the fact that the sacrum is not as mobile as the rest of the spine, there are no intervertebral discs in it. But there are many very tight ligaments that provide bone bonding strength.
In the sacral bone, the following parts are distinguished:
- pelvic part facing inward;
- dorsal or posterior surface;
- two lateral lateral parts;
- wide base facing up;
- narrowed apex pointing down.
Features of the sacral department
The sacrum is the backbone of the spine, its junction with the lower body. Due to this arrangement and the functions performed, this spine has several features:
- it consists of five fused vertebrae;
- this department takes on all the weight of the spine;
- the sacrum is a single bone in the shape of a triangle directed with the tip downward;
- there are no discs between the vertebrae;
- the sacrum forms the posterior wall of the pelvis;
- it is fixed by strong ligaments attached to the pelvic ring;
- the posterior surface of the sacrum is convex and has five vertical ridges, which are tubercles located one above the other;
- when connected to the lumbar vertebra, the sacrum forms a special joint, which is a large protrusion directed into the pelvic cavity;
- 5, the sacral vertebra connects to the coccygeal department, forming the sacrococcygeal joint.
What are the functions of the sacral vertebrae
The sacrum assumes the full weight of the body. It is designed to ensure human stability when walking and a strong connection with the pelvic bones. In addition, the special structure of the sacral section is necessary in order to protect the lower part of the spinal canal. For its communication with the pelvis and lower extremities, the sacral vertebrae have several symmetrically located openings. They include nerve fibers and blood vessels. The sacral canal runs along the entire length of the bone and is slightly curved due to the special structure of the sacrum.
So, all the sacral vertebrae fused. Five ridges extending along the posterior surface of the sacrum remind us that they were once separate. These are small tubercles arising from the fusion of the vertebrae, their spinous, transverse processes, as well as the upper and lower articular processes. This structure provides protection for nerve roots and blood vessels.
Features of the coccygeal department
The coccyx has an even more interesting structure. It consists of 3-5 vertebrae, but underdeveloped and completely fused together. In shape, the tailbone resembles a bird's beak. Its peculiarity is that in men it connects with the sacrum completely motionless. And in women, it can deviate backwards during childbirth to provide the baby with a passage through the birth canal. The coccygeal vertebrae also perform important functions. In addition to being the backbone of the spine and providing support for movement and bending, many nerve roots pass to the pelvic organs and lower extremities.
Sacral injuries
Despite the strength of the sacral bone, as well as its fixed position between the pelvic ring, this section is also prone to damage and injury. The mobile joints here are located only at the junction of the 1st sacral vertebra with the 5th lumbar, as well as where the remaining lateral processes connect to the pelvic bones. It is in these places that injuries most often occur. In the department itself, only bruises or fractures of the sacral vertebrae are possible.
Due to the structural features in the sacral region, the most common injuries that occur in other parts of the spine do not occur. Since there are no intervertebral discs, there are no diagnoses such as “hernia” or “discogenic radiculitis of the sacral region”. It is also impossible displacement of the sacral vertebra in adults, since these elements are firmly fused. And in children this happens very rarely due to the special strength of the ligaments and the protection of the sacrum with the pelvic bones.
Causes of sacral damage
Why then is the sacrum also prone to injury? There are several reasons for this:
- congenital pathologies of the structure of the spine;
- with an increase in the pelvic organs, there is a squeezing of the vessels leaving the sacral canal, which leads to venous congestion;
- with increased loads on the sacrum, the joint capsule can increase in size, as a result, edema develops, and the tissues begin to compress the nerve roots.
These pathologies can lead to malnutrition of bone tissues and their increased fragility. But most often, fractures of the sacrum occur when exposed to great force, for example, during road traffic accidents, falls from a height, strong impacts.
Features of injuries of the sacrum
The main feature of damage to this spine is that a person can move even with a fracture of the sacral bone. Very strong ligaments connecting the sacrum to the pelvic bones help maintain body stability. But since this is still part of the spine, increased activity of the injured person during injury can lead to damage to the spinal cord, rupture of blood vessels or nerve roots. The consequences of this relationship may be impaired urination, complications of the pelvic organs, and paralysis of the lower extremities. If the young woman had a fracture and she did not receive timely medical assistance, then she will not be able to give birth to a child on her own.
What to do if the sacral vertebrae are damaged
After any injury, especially if there is a suspicion of a sacrum fracture, it is necessary to contact a medical institution. On their own, before providing professional help, you can apply cold to the place of damage, and with severe pain, take pain medication. It is not recommended to warm the injury site, as this will increase swelling and the inflammatory process, can lead to bleeding and other complications. It is better for the victim to lie on a flat surface and try not to move.