There are several bends in the spine.

Also known as the spine, it consists of specially shaped vertebrae and intervertebral discs. It is located in the middle of the back, the upper part is connected with the skull, the middle part is connected with the ribs, and the lower part forms the pelvis with the hip bone. From top to bottom, there are 7 cervical vertebrae, 5 thoracic vertebrae 12, 5 lumbar vertebrae, 5 sacrum 1 root (composed of 5 sacrum) and 0 coccyx 1 root (composed of 4 coccyx). A longitudinal spinal canal with a spinal cord is formed in the spine from top to bottom.

Under normal circumstances, the spine has four bends, which are S-shaped when viewed from the side, namely cervical lordosis, thoracic kyphosis, lumbar lordosis and stork kyphosis. Long-term incorrect posture and some diseases (such as thoracic tuberculosis, wet spondylitis, etc. ) can make the spine form abnormal bending, such as hunchback.

The spine is the pillar of the body, located in the middle of the back, with the upper end connected to the skull and the lower end reaching the tip of the coccyx.

The spine is divided into five parts: neck, chest, waist, sacrum and tail. It is long and active, like a scaffold, hanging on the chest wall and abdominal wall. The lower part is relatively short and fixed. The weight of the body and the impact it receives are transmitted to the lower limbs.

The spine is composed of vertebrae and intervertebral discs, which is a very flexible and movable structure. With the exercise load of the body, the shape of the spine will change considerably. The activity of the spine depends on the integrity of the intervertebral disc and the coordination between the articular processes of the related vertebrae.

The length of the spine, 3/4 consists of vertebral body, 1/4 consists of intervertebral disc.

The spine consists of 26 vertebrae, namely 24 vertebrae (7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae), 1 sacrum, 1 coccyx. Since the sacral system is composed of five and the coccyx is composed of four, the normal spine can also be composed of 33. (as shown in the figure: the side of the spine || the back of the spine)

So many vertebrae, because there are strong ligaments around them, can maintain considerable stability, and because there are intervertebral joints connected with each other, they have considerable mobility. Although the range of motion of each spine is very small, if all of them move together, the range will increase a lot.

The front of the spine is formed by the accumulation of vertebral bodies, and the front of the spine is adjacent to the internal organs of the chest and abdomen, which not only protects the organs themselves, but also protects the nerves and blood vessels of the organs, with only a thin layer of loose tissue between them. When the vertebral body is destroyed, in the neck, pus can gather behind the pharynx, or go down the neck to the subclavian fossa, or along the brachial plexus to the armpit; In the chest, it can follow the intercostal nerve to the chest wall or spread to the mediastinum; At the waist, it can descend along the fascia of psoas major, forming an abscess of psoas major, which can flow below the groin or bypass the femoral trochanter to the buttocks.

The posterior part of the spine consists of the pedicle, lamina, transverse process and spinous process of each vertebra. They are connected with each other through ligaments, with shallow surface, only covering muscles, close to the body surface and easy to touch. Lesions at the back of the spine can easily pierce the skin.

Between the front and back of the spine is the spinal canal, which contains the spinal cord. When the surrounding bony structures such as vertebral body, vertebral arch and lamina invade the spinal canal due to fractures or other diseases, it can cause spinal cord compression and even paraplegia, with only a small amount of bleeding and granulation tissue.