The difference between sacroiliac arthritis and lumbar protrusion mainly lies in the different symptoms, different causes and different treatment methods. 1. Symptoms are different: sacroiliac arthritis is more common symptoms of lower back pain, joint mobility disorders. The more common symptoms of lumbar disc herniation are lumbago, radiating pain in the lower limbs, accompanied by numbness and weakness of the limbs. 2. Different causes: sacroiliitis is mainly due to various reasons leading to unilateral or bilateral joint inflammatory changes, such as infection, degenerative disease, long-term use of glucocorticoid drugs and so on. Lumbar disc herniation is usually associated with disc degeneration and abnormal disc development. 3. Different treatments: in the acute stage of sacroiliitis, bed rest is required, and when there is pain, oral aspirin can be taken as prescribed by the doctor for pain relief, and then combined with glucosamine treatment to slow down the degeneration of cartilage. For lumbar disc herniation, physiotherapy, such as laser treatment, is usually recommended as early as possible, and surgical treatment, such as simple interlaminar open nucleus pulposus removal, is required for severe cases. In order to accurately determine sacroiliitis and lumbar herniation, it is recommended to consult a doctor as soon as possible and analyze the condition by X-ray, CT examination, and femoral nerve pulling test detection.