Ankylosing spondylitis is a form of joint inflammation (arthritis) that is long-lasting (chronic) and most often affects the spine. Ankylosing spondylitis commonly causes pain and stiffness, with limited motion in the low back, middle back, neck, hips, chest wall, and heels. Over time, joints in the spine can fuse together and cause a fixed, bent-forward posture. In early ankylosing spondylitis, there is inflammation of the joints and of the ligaments where they attach near the joints. In advanced ankylosing spondylitis, there is: -Fusion of joints in the spine. -Flattening of the normal curve in the low back. Early symptoms include: -Dull pain in the back. -Flares of increased pain. -Limited motion. -Feeling tired. -Eye problems. Advanced symptoms include: -Scarring in the spine that causes the joints to grow together. -Problems with balance and movement. -Trouble breathing. -Vision problems that get worse.Often a flattening of the normal curve of the neck, an increase in the forward curve of the upper back, and bent posture at the hips.