Sciatica is divided into primary sciatica and secondary sciatica. Secondary sciatica is very common and is mainly due to diseases of the spinal canal, including herniated lumbar discs, lumbar spinal stenosis, or spinal tumors compressing the spinal cord and nerve roots. Another condition is piriformis syndrome, where the sciatic nerve exits; if there is narrowing here, it can also cause sciatica. Therefore, clinically, one starts with secondary sciatica, conducting either a lumbar spine CT scan or an MRI, which can basically clarify the location causing the compression. Another type is called primary sciatica, which is caused by inflammation of the sciatic nerve, and is an internal medicine disease, not an orthopedic disease. This requires an electromyography (EMG). After completing the EMG, the diagnosis can generally be made based on the injured muscle or the muscle with abnormal electromotor conduction. Thus, the routine examinations for sciatica are X-rays, CT, MRI, and the non-routine examination is the EMG.