The relationship between muscle tenderness and craniomandibular disorders: a study of 35-year-olds from the general population.

Of a random sample of 345 subjects aged 35 years and drawn from the general population of Västerbotten County, Sweden, 276 (80%) participated in an epidemiologic survey on muscle tenderness of the jaw, neck, shoulder, arm, hand, and calf, and on the prevalence of signs and symptoms of craniomandibular disorders. The control group consisted of 144 subjects (52%) who had no tenderness. The remaining subjects were separated into groups: (1) 59 subjects (21%) with tenderness only in jaw muscles; (2) 26 subjects (9%) with tenderness only in neck/shoulder muscles; (3) 39 subjects (14%) with tenderness in muscles of the jaw and neck/shoulder; and (4) eight subjects (3%) with tenderness in all palpated muscles of the neck, shoulder, arm, hand, and calf. Women were found to have palpation tenderness significantly more often than men (P < .05). The main finding of this study was the presence of a significantly higher proportion of signs and symptoms of craniomandibular disorders in the group who had both jaw muscle tenderness and neck/shoulder muscle tenderness and in the group who had generalized tenderness than in the control group. The results indicate that in epidemiologic and clinical research of craniomandibular disorders, a distinction between local, regional, and general tenderness should be made since the etiology may differ.