Most lumbar disc herniations are postero-lateral, due to the structure of the lumbar disc. We know that the lumbar disc is composed of two layers of fibrosis in the outer layer and the nucleus pulposus in the inner layer, and the fibrous ring is composed of fibers that cross at 60 degrees. There are also some patients with central herniation, so patients with central herniation usually have mainly low back pain. The posterior lateral type of herniation will mostly compress the nerve roots on both sides, and the pain is mainly radiated in the lower limbs. There is also a small percentage of discs that protrude into the cartilage plate of the upper and lower vertebral body, which we also call Xu Mo’s nodes.