Patients with ankylosing spondylitis are advised to sleep in a hard bed and to try to stay in a flat position at night to ensure the normal shape of the spine. Ankylosing spondylitis is a rheumatic disease that affects the sacroiliac joints, spine and peripheral joints of the body. In the later stages of the disease, spinal deformities and spinal ankylosis may occur. The clinical manifestations of ankylosing spondylitis are mainly stiffness and pain in the lumbosacral and lumbar back. Many patients unconsciously develop chest pain in these areas, and even prefer to sleep at night with one side curled up to alleviate the pain, but if you do not pay attention to the position for a long time will accelerate the deformity of the spine, especially the formation of the posterior convexity deformity, which is often referred to as the formation of hunchback.