Ankylosing spondylitis (AS) is a type of arthritis in which inflammatory processes lead to stiffness and fusion of vertebrae and other joints. Because AS involves axial (spine) changes detected with radiographic imaging, it can also be called radiographic axial spondyloarthritis.
What is ankylosing spondylitis?
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•Last Updated: May 16, 2025
Ankylosing spondylitis is a form of arthritis characterized by inflammation that causes stiffness and fusion of the vertebrae and other joints. It is also referred to as radiographic axial spondyloarthritis due to the axial changes that are observable through imaging.