Ankylosing spondylitis is a painful, progressive inflammatory disease of the spine. It can also affect other joints, tendons and ligaments and other areas, such as the eyes and heart.
The exact cause is unknown. It typically causes morning stiffness in the low back along with a deep aching feeling. Loss of spinal mobility is common. There is no definitive treatment, but a regular exercise programme can maintain flexibility of the spine and other affected joints.