When looking at a CT examination film of a herniated lumbar disc, it is important to first clarify the normal anatomical shape of the lumbar vertebrae. The normal lumbar spine shows kidney-shaped tissue in cross-section with a depression in the middle. Secondly, the normal physiological organization of the spinous process of the vertebral plate as well as the nerve roots must be clarified, and finally, the density of the lumbar intervertebral disc under normal conditions must be known. The density of lumbar discs is higher than fluid but lower than bony density. When suffering from a lumbar disc herniation, the lumbar spine is not kidney-shaped, which is manifested by the disappearance of the posterior depression, and a distinct protruding soft tissue shadow can be seen, that is, a lumbar disc herniation. It is then necessary to determine whether the lumbar disc is protruding posteriorly or laterally and posteriorly, and whether it is compressing the spinal cord, the dural sac, and the nerve roots.