Lumbar 4-5 disc bulge may be caused by lumbar degeneration, strain, trauma, etc.. 1. Degeneration of lumbar vertebrae: with age, the intervertebral disc will degenerate, so that the nucleus pulposus decreases in elasticity, the fibrous annulus reduces the toughness, and is prone to rupture under the action of strain and external force, resulting in the disc protruding into the vertebral canal, and causing the disc to bulge out of the lumbar 4-5 vertebrae. 2. Strain: daily physical labor, poor sitting posture, driving, sports, etc., can also lead to intervertebral disc force, backward protrusion, causing lumbar 4-5 disc bulging. 3. Trauma: If the lumbar region is traumatized, such as acute lumbar sprain, collision, etc., it can also lead to lumbar 4-5 disc bulging. Lumbar 4-5 bulging disc is closely related to age, occupation, pregnancy and other factors, if the onset of the disease, timely medical treatment to avoid aggravation of the condition, affecting the action.