Ankylosing spondylitis (AS) is a form of inflammatory arthritis that predominantly affects the axial skeleton (spine and sacroiliac joints).  Untreated, this condition can lead to progressive loss of movement in the back and fusion of the spine.  It typically affects young men, and often the symptoms of back pain and stiffness have incorrectly been attributed to a back injury for years before the diagnosis is made. 

Learn more: https://aucklandrheumatology.co.nz/AS.html