Evaluation of the Relationship Between Craniovertebral Angle and Fibromyalgia Symptom Severity

Fibromyalgia (FM) is a chronic pain syndrome characterized by widespread musculoskeletal pain, muscle stiffness, joint rigidity, insomnia, fatigue, mood disorders, cognitive dysfunction, anxiety, depression, and general hypersensitivity.

Fibromyalgia is considered a central sensitivity syndrome. Central sensitization refers to a neuronal signal amplification mechanism within the central nervous system that leads to enhanced pain perception. Consequently, patients with FM exhibit an increased receptive field of pain, allodynia, and hyperalgesia.

Headache and temporomandibular disorders (TMD) are among the most common comorbidities in FM, displaying overlapping clinical and pathophysiological features.

Nociplastic pain is defined by the International Association for the Study of Pain as pain arising from altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system causing the pain. The mechanism of nociplastic pain is proposed to involve increased central nervous system sensitization and impaired sensory processing, accompanied by altered pain modulation. Definitive criteria for nociplastic pain have not yet been established. Eight specific disorders associated with central sensitization have been proposed: restless leg syndrome, chronic fatigue syndrome, FM, TMD, migraine or tension-type headache (TTH), irritable bowel syndrome, multiple chemical sensitivities, and whiplash injury.

Central sensitization is classically defined as a consequence of ongoing nociceptive inputs in chronic pain conditions. Its development is reported to be influenced by genetic factors, pain processing disorders in the brain, neuroendocrine and autonomic abnormalities, abnormal cytokines, and immune dysfunction.