fibromyalgia, a form of nonarticular rheumatism characterized by musculoskeletal pain, spasms, stiffness, fatigue, and severe sleep disturbance. Common sites of pain or stiffness include the lower back, neck, shoulder region, arms, hands, knees, hips, thighs, legs, and feet. These sites are known as trigger points. Physical therapy, nonsteroidal antiinflammatory drugs, and muscle relaxants provide temporary relief. Also called fibrositis, soft tissue rheumatism.
