Sleeping on your back is not good for the lumbar spine, mainly in two ways. 1, when sleeping on your back the lumbar muscles, tendons, ligaments, fascia and other soft tissues are not fully relaxed rest, so in the process of sleeping, it will lead to these soft tissues show fatigue, the formation of strain over time, will gradually produce inflammatory lesions, inflammatory metabolites will lead to the surrounding soft tissues become more rigid The inflammatory metabolites will cause the surrounding soft tissues to become stiffer and less elastic, and will lead to adhesions in the surrounding soft tissues, also with the passage of time, calcium salts are gradually deposited, forming calcification and hyperplasia, which will lead to more pronounced symptoms of lumbar pain, and sometimes lower extremity numbness, radiating pain, intermittent claudication and other related complications. 2, when sleeping on the stomach, because the body lumbar state of overextension, will lead to hypertrophy of the ligamentum flavum on the posterior side of the spinal canal. This will lead to narrowing of the spinal canal over time, which will cause extrusion and stimulation of the cauda equina nerve or nerve roots of the lumbar spine, and will lead to numbness of the lower limbs and intermittent slope and other related symptoms.