Lumbar disc herniation is one of the more common disorders, mainly because the lumbar intervertebral disc parts (nucleus pulposus, fibrous ring and cartilage plate), especially the nucleus pulposus, have different degrees of degenerative changes, under the action of external factors, the fibrous ring of the disc ruptures, and the nucleus pulposus tissue protrudes (or prolapses) from the rupture in the posterior or vertebral canal, resulting in the adjacent spinal nerve roots suffer from irritation or compression, thus producing lumbar pain The result is a series of clinical symptoms, such as numbness and pain in one or both lower limbs. So, what tests are needed for lumbar disc herniation? 1, X-ray The density of the nucleus pulposus, fibrous ring and cartilage plate included in the lumbar intervertebral disc is low and does not show up under X-ray, so clinically the lumbar spine X-ray plain film of patients with lumbar herniation can have only some non-specific changes or even no abnormal changes. However, X-rays can detect degenerative changes and structural abnormalities in the lumbar spine, which is important for suggesting disc degeneration and can exclude other lumbar spine disorders, such as lumbar tuberculosis, tumors and lumbar spine slippage. A typical patient with lumbar disc herniation can make a preliminary diagnosis through history, physical signs and X-ray plain film. 2.CT examination CT of the lumbar spine can clearly show the location, size, shape and nerve root and dural pressure of the herniated disc, and also show the hypertrophy of the ligamentum flavum, small joint hyperplasia, narrowing of the spinal canal and lateral saphenous fossa. The accuracy rate of the diagnosis of lumbar disc herniation reaches 80%-92%. 3, MRI MRI has no radiation, can be multi-directional imaging (cross-sectional, coronal, sagittal and oblique), shows better anatomical details, is more sensitive to subtle pathological changes in tissue structures (such as infiltration of bone marrow), and can exclude nerves and spinal tumors, etc. For some fall into the spinal canal of the nucleus pulposus tissue will not be missed. 4, myelography Myelography uses the space of the subarachnoid space in the spinal canal, injects contrast and then takes a film under X-ray to show the internal structure of the spinal canal. At present, water-soluble contrast agent is commonly used, which can show the dural cavity, cauda equina and nerve root sheath more clearly, and the diagnosis of lumbar disc herniation can reach about 90%, and the main X-ray manifestations are the signs of dural sac compression and the signs of nerve root sheath compression. However, due to the widespread use of CT and MRI in the clinic, which are non-invasive and have a higher diagnostic rate, the use of myelography in the clinic has been greatly reduced, and because of its large side effects, which may even cause serious conditions such as paraplegia, it is now advocated that it should be used with caution. Electromyography is a method of electrophysiological examination of peripheral nerves and muscles, which can be used to observe and record the electrical activity of muscles at rest, active contraction and stimulation of the peripheral nerves innervating them, and can also be used to measure the conduction velocity of peripheral nerves. In lumbar disc herniation, electromyography reflects the status of the corresponding nerve root by examining the excitability of the muscles in both lower extremities and determines the segment of the disc herniation and nerve root compression based on the distribution of abnormal electrical activity. In patients with spinal nerve root and cauda equina nerve compression, the positive rate of EMG can reach 80%-90%, but it is not the first choice compared to CT and MRI, and can be used as an aid to diagnose and determine the compression of nerve roots, and can also be used as one of the indicators to determine the recovery of nerve roots after treatment.