Nerve entry points - The anatomy beneath trigger points

Abstract

Introduction: Myofascial trigger points (MTrPs) have been the subject of considerable scientific research for almost forty years. In their seminal paper, Travell and Simons described a model based on the presence of highly irritable, palpable nodules within taut bands of muscle. Since then, a significant number of studies have increased our understanding of the phenomenon, which has, in turn, resulted in refutation of the original model. Alternative models have explained certain properties of MTrP but fail to provide an explanation of their spatial distribution. The aim of this paper was to propose a hypothesis connecting MTrPs and distinct points along the course of the nerve called nerve entry points (NEPs). A literature review was performed in order to identify studies to support hypothesis development.

Methods: Literature search of digital databases.

Results: A total of 4631 abstracts were screened; 72 were selected for further review. Four articles made a direct connection between MTrPs and NEPs. Another fifteen articles provided high-quality data regarding the distribution of NEPs, thus strengthening the hypothesis.

Conclusions: There is sufficient evidence to hypothesise that NEPs are the anatomical basis for MTrPs. This presented hypothesis addresses one of the crucial issues in diagnosing trigger points, which is the lack of repeatable and reliable diagnostic criteria. By connecting subjective phenomenon of trigger points with objective anatomy, this paper provides a novel and practical foundation for identifying and treating pain conditions associated with MTrPs.

Keywords: Clinical reliability; Diagnosis; Hypothesis development; Nerve entry points; Trigger points.