Cephalic muscle tenderness and pressure pain threshold in a general population.

Tenderness and pain thresholds in pericranial muscles were studied in a general population. A random sample of 1000 adults aged 25-64 years was drawn as part of the Glostrup Population Studies, and 740 adults were examined. This study was part of a multifacetted, epidemiological study of different headache disorders according to the new headache classification. Manual palpation and pressure pain threshold with an electronic pressure algometer were performed by observers blinded to other information such as the person's history of headache, previous illness and mental state. The muscles most commonly tender to manual palpation were the lateral pterygoid (55%), the trapezius (52%), and the sternocleido-mastoid muscles (51%). Females were more tender than men in all the muscles examined by manual palpation. In total, the young age group was more tender than the old age group (P = 0.03). Pressure pain thresholds on temporal muscles showed lower thresholds in women than in men (P less than 10(-3)), and in the total population thresholds increased with age (P less than 0.05). No side-to-side difference in tenderness by manual palpation was found, while the right side showed increased pain thresholds in right-handed individuals (P less than 10(-4)). No side-to-side difference was found in left-handed persons. This study provides data about the normal population and forms the necessary basis for evaluating the importance of muscle tenderness in headache subjects and other selected groups.