What condition can lead to a gradual inability to flex and bend the back?

Spondylarthritis is a group of inflammatory diseases that primarily affects joints of the spine and can lead to a gradual inability to flex and bend the back. This condition often involves symptoms such as stiffness and pain in the lower back, which can progress to more severe limitations in mobility over time. The inflammation associated with spondylarthritis can lead to changes in spinal structure, such as the formation of new bone growth, which ultimately contributes to the reduced range of motion.

While other conditions listed, such as arthritis and osteoarthritis, may also affect the joints and lead to stiffness or pain, they typically do not have the same degree of impact on spinal mobility as spondylarthritis. Fibromyalgia, on the other hand, is characterized by widespread musculoskeletal pain and does not specifically cause a progressive inability to flex or bend the back, making the focus on spinal mobility less relevant in this condition. Thus, spondylarthritis uniquely connects to the gradual limitations in spinal flexibility.