The Natural History of Upper Trapezius Myofascial Trigger Points: Comparison of Local and Remote Tissue Milieu in Normal Muscle, Latent and Active Myofascial Trigger Points Over Time

Preliminary data suggest that patients with active myofascial trigger points (MTrPs) have a significantly different biochemical profile within the local milieu of the MTrPs compared to those without MTrPs or those with a latent (non-symptomatic) MTrP. An important question to answer is whether anatomical loci, remote from active or latent MTrPs have similar biochemical profiles to the MTrP itself. These remote sites should be evaluated to help distinguish whether MTrPs have local biochemical profiles or are associated with a more widespread phenomenon. We will select three groups of subjects based on the following characteristics \[1, 2, 3 below\]. We will sample GB-21 in the upper trapezius muscle and LV-7 (posterior and inferior to the medial condyle of the tibia in the upper portion of the medial gastrocnemius) standardized sites for pH, muscle metabolites, inflammatory mediators, arachidonic acid derivatives, neuropeptides, etc. The goal of this study is to determine whether the local biochemical milieu of an active MTrP is the same as the biochemical milieu at anatomical sites remote from the MTrP. The acupuncture points GB-21 and LV-7 are selected specifically to standardize the locations of a sampling point in three carefully selected groups: 1. healthy subjects without neck pain and who have no MTrPs identified by palpation bilaterally in GB-21, and who have no MTrPs identified by palpation bilaterally in LV-7, 2. healthy subjects without neck pain in whom latent MTrPs are identified by palpation in GB-21 in one of the upper trapezius muscles, and who have no MTrPs indentified by palpation bilaterally in LV-7, 3. healthy subjects complaining of neck pain of less than 3 months duration with active MTrPs identified by palpation in GB-21 in one of the upper trapezius muscles, and who have no MTrPs identified by palpation bilaterally in LV-7.