Ankylosing spondylitis is primarily characterized by involvement of the elbow joints, but it can also be accompanied by extra-articular manifestations such as iritis and pain in the heel, and severe cases may present with spinal stiffness and deformity. The cause of the disease is unclear, but studies suggest it is related to genetic and environmental factors, with a significant familial aggregation. Diagnosis requires a combination of clinical symptoms, blood tests including HLA-B27, and imaging such as CT or MRI of the sacroiliac joints to confirm inflammation or damage to these joints. To diagnose ankylosing spondylitis, these three criteria must be met. The most important factor is the presence of clinical symptoms that persist for more than three months, improve with activity, and do not significantly improve with rest. This is a typical characteristic of ankylosing spondylitis.