There are two groups of signs for lumbar protrusion, one is lumbar and spinal signs and the other is nerve root signs. (1) Lumbar and spinal signs ① Scoliosis: the patient’s spine is mostly scoliosis, and scoliosis is a protective measure to keep the nerve away from the protrusion, so that the compression is relieved and the pain is reduced. ② Change in lumbar curvature: the physiological anterior convexity of the lumbar spine disappears and may even be convex backwards, which is also a protective measure to relieve pain. ③ Restriction of spinal movement: The movement of the spine in all directions, such as posterior extension, forward flexion, lateral bending and rotation, is restricted to varying degrees. ④ pressure point: paraspinal herniated lumbar disc may have pressure pain and radiates to the lower limbs, and the pressure pain is obviously in the corresponding paraspinal area on the affected side. Some people have statistics: the appearance rate of pressure pain with radiating pain is 61.5%, and the rate of only pressure pain without radiating pain is 38.5%. (2) Nerve root signs ①Straight leg elevation test: the positive rate is more than 90%, and radiating pain is present between 15° and 65°, which is a useful sign for this disease. (ii) Head-up and neck flexion test: the patient lies on his back with both lower limbs straight and flat, and slowly raises his head and flexes his neck, at which time the radiating pain of the lower limbs is positive. (③) Sensory disorder: there is sensory (including pain, touch and temperature sensation) disorder in the innervated area of the squeezed nerve root. The disc herniation mainly invades the lower two lumbar nerves and sacral 1 nerve roots, so it is helpful to determine the area of sensory alteration for localization. ④Motor impairment: the muscle function innervated by the invaded nerve roots is often reduced. The lumbar 4-5 disc herniation compresses the lumbar 5 nerve root and weakens the dorsiflexion of the innervated toes, accounting for 71.5% of cases. When the sacral 1 nerve root is damaged, the toe and foot plantarflexion force is reduced, and it is often impossible to stand on the ground with the toe of the affected side alone. ⑤ Reflex changes: knee reflex can be reduced in lumbar 3 and 4 disc herniation, and can be unchanged in lumbar 4 and 5 disc herniation, but can also be hyper or hypo. Achilles tendon reflex can be hypo or absent in up to 85% of cases of lumbar 5 sacral 1 herniation.