Sleeping with a pillow under the leg, the main effect is twofold: 1, relax the tension of the nerves in the lower limbs; 2, relax the tension of the muscles in the lower limbs and lumbar region. Because the nerves of patients with lumbar disc herniation and lumbar spondylolisthesis are compressed and tension is increased, by padding a pillow behind the legs and flexing the knee and hip joints, the tension of the sciatic nerve can be reduced and the edema and inflammatory degree of the nerves can be reduced. When the pillow is padded behind the knee joints of both lower limbs, the bilateral iliopsoas, quadriceps and tibialis anterior muscles will be relaxed, which facilitates the recovery of muscle fatigue. Therefore, the pillow under the legs while sleeping mainly plays a role in relaxing the muscles and reducing the nerve tension.