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This chapter is dedicated to the memory of David G. Simons, MD (1922–2010)
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Chapter Objectives
At the conclusion of this chapter, the reader will be able to:
Identify the main historical events in the development of the myofascial trigger point construct and recognize the primary influences.
Understand the main principles of muscle physiology and the motor endplate that are important in the understanding of myofascial trigger points.
Understand the expanded integrated trigger point hypothesis.
Understand the motor, sensory, and autonomic phenomena associated with myofascial trigger points.
Recognize the importance of palpation and the recommended criteria for identification of myofascial trigger points with reference to current palpation reliability studies.
Recognize the importance of the taut band, tender nodule, and referred pain pattern.
Recognize and understand the main noninvasive interventions used to treat myofascial trigger points and the evidence available to support their use.
Recognize and understand the invasive interventions available, with special reference to trigger point dry needling, and understand the rationale and evidence for its application.
Recognize common perpetuating factors and formulate current management strategies.
Learn the specific technique for palpation of myofascial trigger points.
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HISTORY AND DEVELOPMENT
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Drs. Janet G. Travell (1901–1997) and David G. Simons (1922–2010) brought myofascial trigger points (MTrPs) to the attention of clinicians and researchers worldwide,1–3 despite the fact that MTrPs had been described as early as the 16th century4 (Box 16-1). As a cardiologist, Travell was strongly influenced by Kellgren, who from 1938 to 1949 described, for the first time, pain referral patterns of muscles and ligaments following injection of hypertonic saline.5-8 In 1940, Steindler introduced the term trigger point.9 Travell was drawn to the potential benefits of muscular trigger point injections and subsequently adopted the term in 1942.10,11 In the early 1950s, Travell and Rinzler described biopsied tissues of hyperirritable trigger points in which no pathological changes were identified and concluded that these must be pathophysiological in nature.10 They also observed that fascia referred pain in a similar fashion, leading Travell to adopt the term myofascial pain. In 1952, a seminal manuscript, which unknowingly mirrored the work of researchers in other continents, was published that described the pain referral patterns of 32 individual muscles.12,13 After hearing Travell lecture on the topic, Simons became involved in 1963. Together, they coauthored several articles and book chapters, in addition to the popular and authoritative texts on this approach.1-3 Evidence supporting the existence and management of MTrPs has grown over the past three decades, with more evidence emerging within the last decade than in the previous two combined (Table 16-1).
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