The lumbosacral joint is the 5th lumbar vertebra and the 1st sacral vertebra, and the adult is the connection between the sacrum through the intervertebral discs and the surrounding soft tissues. The lumbosacral region is at the intersection of the trunk, pelvis and lower limbs, and is located at the junction of the physiological anterior convexity of the lumbar vertebrae and the physiological posterior convexity of the sacral vertebrae, and is subject to the greatest shear forces. There are more than 20 joints in the lumbosacral region, and the joints are often in motion. The lumbosacral region is the connection point between the upper body and the lower limbs, and the activities of the lumbosacral joints are mainly forward flexion, back extension and lateral bending, with less rotational activities.