A syndrome characterized by chronic pain in the muscles and soft tissues surrounding joints, fatigue, and tenderness at specific sites in the body. Also called fibromyalgia syndrome, fibromyositis, fibrositis. Fibromyalgia: a musculoskeletal disease. A common nonarticular rheumatic syndrome characterized by myalgia and multiple points of focal muscle tenderness to palpation (trigger points). Muscle pain is typically aggravated by inactivity or exposure to cold. This condition is often associated with general symptoms, such as sleep disturbances, fatigue, stiffness, headaches, and occasionally depression. There is significant overlap between fibromyalgia and the chronic fatigue syndrome, cfs, (fatigue syndrome, chronic). Fibromyalgia may arise as a primary or secondary disease process. It is most frequent in females aged 20 to 50 years. (From Adams et al., Principles of Neurology, 6th ed, p1494-95)