The term ankylosis stands for loss of mobility of the spine, whereas spondylitis means inflammation of the spine. Therefore, ankylosing spondylitis is a condition where chronic inflammation of spine and sacroiliac joint results in complete fusion of the vertebrae leading to pain and stiffness in the spine. Sacroiliac joints are present in the lower back where the sacrum part of the vertebrae joins the iliac bones.

Ankylosing Spondylitis is a systemic disease affecting other tissues and organs throughout the body. It can cause inflammation of faraway joints and organs such as the eyes, heart, lungs and kidneys.

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