Any joint can be involved, but the spinal joints are predominantly involved. In the early stage, there are different degrees of pain around the joints, accompanied by muscle spasm and stiffness, morning stiffness is obvious, the disease is heavy after fixing a certain position for a long time, light day and night; in the later stage, because the inflammation has basically disappeared, so there is no pain in the joints, but the main manifestation is spinal fixation and ankylosis, fixed anterior tilt of the cervical spine. The spinal column is retroverted, the thorax is often fixed in the exhalation state, the lumbar spine physiological bending is lost, the hip and knee joints are severely flexed and contracted, the eyes stare at the ground when standing, the body weight shifts forward, individual patients can be severely disabled, long-term bedridden, unable to take care of themselves. I. How does ankylosing spondylitis sacroiliac arthritis manifest itself? Most patients first present with symptoms of sacroiliac joint involvement, manifesting as back straightening and pain radiating to one or both hips, and occasionally to the thighs, which can further develop into the knee joint. Due to the local inflammation of the sacroiliac joint, the lower limb extension and elevation sign is usually positive. The sacroiliac joint is symmetrically involved, and the pubic symphysis may also be involved. Second, how does ankylosing spondylitis lumbar arthritis present? Although the sacroiliac and lumbar joints are involved at the same time, most patients have back pain and dysfunction caused by lumbar spine arthropathy. Spinal ankylosis may be caused by muscle spasm induced by lumbar osteoarthritis. On examination, there may be direct tenderness in the lumbar osteoarthrosis joints, marked spasm of the paravertebral muscles, straightening of the waist, restriction of movement, and loss of normal physiological curvature of the waist. Third, how does ankylosing spondylitis thoracic arthritis behave? The progressive upward development of spondylitis, the thoracic joints can also be involved. Patients have upper back chest pain and a sense of restricted thoracic expansion movement. The thoracic pain is usually pronounced on inspiration, and the limitation of thoracic expansion is mainly due to the involvement of the rib joints, the sternal stalk-sternal body joints, the rib and rib cartilage joints, and the sternoclavicular joints. The thorax can cause dyspnea, especially during exercise, but pulmonary function measurements are not significantly altered, due to the increased amplitude of the diaphragm compensating for the restricted thoracic expansion. As the disease progresses, significant kyphosis can occur, and the thorax begins in the expiratory state. Fourth, what is the manifestation of cervical arthritis in ankylosing spondylitis? A small number of patients may develop cervical arthritis in the early stages, and as the disease progresses, cervical lordosis or lateral lordosis may occur, with the head in a fixed forward-flexed position, partially or completely restricted in posterior bending, rotation, and lateral bending, and a significantly smaller spatial field of vision.