Ankylosing Spondylitis (AS), where "A" stands for fusion and "S" for spine, refers to the condition where the bones and joints of the spine are fused together. Ankylosing Spondylitis is defined as a chronic inflammatory disease primarily affecting the axial skeleton and major limb joints. It is characterized by fibrosis and ossification of the intervertebral discs’ annulus fibrosus and nearby connective tissues, as well as ankylosis (stiffening) of the joints. It presents as a sterile inflammation occurring in the spine. However, it is not solely limited to the spine as it also involves the axial bones and major limb joints. The pathological hallmark of the disease includes inflammation mainly at the sacroiliac joints and points of attachment to the spine, leading to joint stiffness and calcification of the spinal ligaments and joints. The disease progression begins at the sacroiliac joint, spreading upwards through the entirety of the spine, and eventually stops at the cervical vertebrae. Symptoms start with pain in the early stages, followed by restricted mobility in the intermediate phase, and ultimately leading to deformities of the abdomen and back, culminating in severe hunchback. The exact cause of Ankylosing Spondylitis remains unclear, with various theories proposed but none universally accepted. Additionally, it is categorized under rheumatologic and immunologic disorders.