Most of the symptoms of sciatica are caused by the following diseases: 1. The most common disease that can cause sciatica as a symptom is lumbar disc herniation. There is lumbar intervertebral cartilage between the lumbar vertebrae and the vertebral body, and this cartilage is bound by the vertebrae and the lateral fibers within a certain space. Once the cartilage outer fibrous ring, for some reason, ruptures, it causes the intervertebral disc cartilage to be squeezed out and the protruding lumbar intervertebral disc stimulates the soft tissues around the lumbar spine. This includes the lumbar nerve, and the sciatic nerve is formed by the downward extension of the lumbar nerve. Once the lumbar nerve is stimulated, it will cause the sciatic nerve to be stimulated, causing symptoms of sciatica; 2. The soft tissue around the sciatic nerve is compressed, which will also cause the sciatic nerve to be stimulated, causing symptoms of sciatica. For example, in patients with pear-shaped muscle syndrome, the pear-shaped muscle is stimulated by cold, exertion and other external stimuli, triggering edema of the pear-shaped muscle. The sciatic nerve passes through the middle of the pear muscle, and once the pear muscle swells, it will stimulate the sciatic nerve and cause painful symptoms.