What is the physiological role of the lumbar intervertebral discs? Connective role: The disc connects the two vertebrae above and below and allows a certain degree of mobility between the vertebrae, while maintaining the continuity of the spine and maintaining height. As the vertebrae develop, the disc increases in height, thus increasing the height of the spine. The intervertebral discs maintain the height of the vertebral connections while maintaining the size of the intervertebral foramina so that the nerve roots have enough space to pass through the foramina. Maintaining the physiological curvature of the spine, the thickness of the intervertebral disc varies in different parts, including the lumbar intervertebral disc which is thick in the front and thin in the back, giving the spine a physiological curve of forward convexity of the lumbar spine. The intervertebral disc also has a very important role in absorbing shock. Why does the lumbar intervertebral disc have a shock-absorbing effect? This is the most important physiological role of the intervertebral disc. The nucleus pulposus is a semicolloid composed of mucopolysaccharide protein complex, chondroitin sulfate and a large amount of water, which is surrounded by the fibrous ring and cartilage end plate and cannot be compressed because it contains a large amount of water, and the nucleus pulposus deforms and moves very little within the fibrous ring when the spine is active, changes shape and position with the action of external forces, and transmits external forces evenly to the fibrous ring and cartilage end plate, so that the surface of the vertebral body is subjected to the same force, and when When there is a certain inclination between the vertebral bodies, the pressure is decomposed by the semi-liquid component of the nucleus pulposus, so that the entire intervertebral disc is subjected to the same pressure, and the pressure on the fibrous ring and cartilage end plate is minimized, which eventually plays the role of protecting the spinal cord and the important organs of the body. The nucleus pulposus also has a certain permeability. During the day, the fluid in the nucleus pulposus is extravasated due to upright labor, and at night, the fluid seeps into the nucleus pulposus after lying down, so that people have to get up in the early morning about 1-2M higher than before sleeping.