Where is the intervertebral disc

The intervertebral disc is an important part of the human body. If there is a protrusion in this part, it will cause lumbar disc herniation, causing the patient to experience symptoms such as soreness and difficulty in movement. Therefore, it is recommended that everyone should understand the treatment methods of lumbar disc herniation. The intervertebral discs are located from the waist to the chest. The intervertebral discs in the waist are the thickest and are mainly used to support the whole body, while the intervertebral discs in the chest are the thinnest and are mainly used to prevent muscles from compressing the heart.

The cartilaginous connection between the vertebral bodies of two adjacent vertebrae is called an intervertebral disc. It consists of the annulus fibrosus on the outside and the nucleus pulposus in the center.

Anatomy

1. An adult has a total of 23 intervertebral discs (there is no intervertebral disc between the 1st and 2nd cervical vertebrae). The intervertebral discs in the chest are the thinnest, about 2 mm; the intervertebral discs in the waist are the thickest, about 10 mm. The total thickness of all intervertebral discs accounts for about 1/4 of the total length of the spine above the sacrum. The intervertebral disc consists of two parts: the peripheral annulus fibrosus and the central nucleus pulposus. The annulus fibrosus is composed of multiple layers of staggered fibrous cartilage rings, which firmly connect the vertebrae together. It has great elasticity and toughness. In addition to bearing pressure, it can also prevent nucleus pulposus from overflowing. The nucleus pulposus is a white gelatinous substance that is elastic. When the nucleus pulposus is affected by gravity, it expands in all directions and squeezes the annulus fibrosus to extend and expand in all directions.

2. When the spine moves, the intervertebral disc produces a wedge-shaped deformation. If the spine bends forward, the front half of the intervertebral disc is flattened and thinned, while the back half thickens and the nucleus pulposus moves backward; the opposite is true when the spine extends backward. If the spine bends to the right, the right half of the intervertebral disc becomes thinner and the left half becomes thicker, and the nucleus pulposus moves to the left; the opposite changes occur when the spine bends to the left. Therefore, the intervertebral disc has the functions of increasing the range of spinal movement, bearing pressure, cushioning shock, and protecting the brain and spinal cord; it is also the main reason for changes in height sooner or later.

3. The blood vessel distribution of the intervertebral disc is richer in childhood than in adults, and can reach the deep layer. With the increase of age, the deep blood vessels gradually become fewer and their caliber also becomes smaller. The nerves of the intervertebral disc are only distributed in the superficial layer of the annulus fibrosus, while there are no nerves in the deep layer and nucleus pulposus.