Tender stie localization in muscle pain

Discreteness of pain sites has been suggested in the literature and observed by clinicians; however, there are no supportive laboratory data. Discreteness is important because of potential false-negative findings during the clinical examination and because of potential error during pressure pain threshold (PPT) measurements due to instrumental decrease in proprioception compared to palpation. Forty-five patients with myogenous pain were examined with palpation using the criterion of pain-replication to separate subjects by pain type: referred or non-referred. PPT measures were taken at the pain site with a strain-gauge algometer. One subject during the study remarked that the PPT measurements were not on his pain site; subsequent measurements were taken using subject feedback for algometer placement. The PPT for nonreferred pain did not change when subject-feedback was added; the variance of the PPT for referred pain was significantly smaller in the subject-feedback condition compared to the no-feedback condition. The results suggest that sites producing referred pain may be more discrete than those producing non-referred pain, that discreteness of pain sites may contribute to examination error, and that subject feedback may be important to improve PPT measurement validity.