Most people are still unfamiliar with ankylosing crestitis, but it is really happening around us, and many patients call it the “undead cancer”. Is it that serious? Ankylosing Spondylitis (AS) is a disease characterized by inflammation of the sacroiliac joints and the attachment points of the spine. It is a chronic inflammatory disease characterized by inflammation and ossification of the crest joints and ligaments of the lumbar, cervical and thoracic segments as well as the sacroiliac joints, often involving the hip joint, and other peripheral joints. The main clinical manifestations are back, back, neck, hip, and hip pain, as well as joint swelling and pain, and in severe cases, crestal deformity and joint ankylosis. Because of the severity of the symptoms and the difficulty of treatment, it can gradually lead to joint deformity, loss of function, and even disability. The prevalent group is 10 to 40 years old, with an average age of 25 years. It is more common in males than females, with a male to female incidence ratio of (2 to 3):1. The incidence is higher in those with a positive family history of AS. The development of ankylosing crepitus is closely related to the human cell-bound antigen (HLA-B27), and there is a clear tendency for family aggregation of inheritance. The genetic component of the disease is influenced by environmental factors (including infection). Genetic factors play an important role in the development of ankylosing cremasteritis. Immune factors also play a role in the etiology. Endocrine, trauma, metabolic disorders and metabolic reactions are also suspected as pathogenic factors. The early stages of ankylosing crestitis are characterized by occasional low back or sacroiliac joint pain. As the disease gradually worsens, the physiological curvature of the lumbar spine gradually disappears, the pain becomes persistent, and the site gradually progresses upward, and abnormalities of the thoracic and cervical spine begin to appear, eventually presenting a hunchback deformity, and patients in advanced stages are often prone to fractures. Many patients are unable to take care of themselves in the late stage of life, and life is worse than death. The term “undead cancer” is actually slightly exaggerated, so the disease should be detected early and treated early to preserve the quality of life as much as possible.