Why does my lower back hurt after a car accident?
Lower back pain after a car accident is usually caused by the sudden compression and twisting force on the lumbar spine, which strains paraspinal muscles, irritates facet joints, and can bulge or herniate a disc. The seatbelt also pins the pelvis while the torso rotates, creating shearing stress through the sacroiliac joint. Pain often appears 24 to 48 hours later as inflammation peaks.