Myofascial trigger points in the suboccipital muscles in episodic tension-type headache

Referred pain evoked by suboccipital muscle trigger points (TrPs) spreads to the side of the head over the occipital and temporal bones and is usually perceived as bilateral headache. This paper describes the presence of referred pain from suboccipital muscle TrPs in subjects with episodic tension-type headache (ETTH) and in healthy controls. Ten patients presenting with ETTH and 10 matched controls without headache were examined by a blinded assessor for the presence of suboccipital muscle TrPs. Diagnostic criteria described by Simons and Gerwin were adapted to diagnose TrPs, i.e. presence of tenderness in the suboccipital region, referred pain evoked by maintained pressure for 10 s, and increased referred pain on muscle contraction. Six ETTH patients (60%) had active TrPs and 4 had latent TrPs (40%). On the other hand, 2 control subjects also had latent TrPs. Differences in the presence of suboccipital muscle TrPs between both groups were significant for active TrPs (P<0.001), but not for latent TrPs. Active TrPs were only present in ETTH patients, although TrP activity was not related to any clinical variable concerning the intensity and the temporal profile of headache. Myofascial TrPs in the suboccipital muscles might contribute to the origin and/or maintenance of headache, but a comprehensive knowledge of the role of these muscles in tension-type headache awaits further research.