MASSAGE TRIGGER POINTS

BY WAI-LEUNG AMBROSE LO, PHYSIOTHERAPIST

INTRODUCTION Trigger points are palpated as tender “knots” or “taut bands” in muscles or ligaments. They may cause local as well as referred pain in a predictable and reproducible pain pattern (1). Most common enigmatic unexplained musculoskeletal pain is believed to be caused by trigger points and truly effective treatment often hinges on accurate identification of these points as sources of the pain (2). However, myofascial trigger points are commonly overlooked or poorly treated as they are yet to be accepted or integrated into teaching, research and practice in mainstream medicine. The aim of this article is to explain the anatomy and pathophysiology of myofascial trigger points and to examine various release techniques and recent research on their clinical application.

WHAT IS A TRIGGER POINT? Trigger points are small circumscribed hyperirritable foci in muscles and fascia. They are often found within a firm or taut band of skeletal muscle, and can arise in virtually any muscle group (see Figure 1). The most common sites (3) are the muscles involved in maintaining posture, such as the: n the levator scapulae n upper trapezius n sternocleidomastoid n scalenes n quadratus lumborum muscles.

THE ROLE OF MYOFASCIAL TRIGGER POINTS IN MUSCULAR PAIN

Myofascial trigger points are small hyperirritable foci in muscles and fascia. Little is known about the exact cause of these trigger points, but they are likely to be due to acute injury or chronic microtrauma to the muscles. Palpation is the only practical way of diagnosing them. They can be treated in various way including injection therapy, manual therapy, surgery and acupuncture. This article will give you a better understanding about the formation and identification of trigger points and evidence-based treatment.

The underlying aetiology of myofascial trigger points appears to be multifactorial, among them: n postural stresses n inefficient biomechanics n repetitive overuse. These three are the most frequently described causes, but unfortunately there is little published evidence about the exact causes.

Trigger points can be either active or latent: n Active trigger points are associated with spontaneous complaints of pain, which may be present at rest or during motion. n Latent trigger points do not cause spontaneous pain, but pain may be elicited with manual pressure or by needling the trigger point. They may restrict range of motion (4) and alter motor recruitment patterns (5).

Figure 1: Trigger points (A) close to the centre of the muscle fibre (ATrP and CTrP) and (B) in microscopic detail, showing how sarcomeres of the involved fibres are longer and thinner than those of uninvolved fibres.

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They can also either be primary or secondary: n Primary trigger points develop independently and not as the result of trigger point activity elsewhere. n Secondary trigger points may develop in antagonistic muscles and neighbouring protective muscles as the result of stress and muscle spasms. It is common to experience a secondary trigger point after a primary trigger

point is eliminated.

WHAT CAUSES MYOFASCIAL PAIN? Trigger points often involve numerous sarcomeres of muscle bands. Regional shortening of sarcomeres on a taut muscle band is palpable as a “contraction knot”, comprising hyper- contracted muscle fibres. The other sarcomeres within the muscle band are also stretched in order to compensate for the missing length of the shortened

BOX 1: MAIN CHARACTERISTICS OF TRIGGER POINTS

Active trigger points n Associated with spontaneous complaints of pain (at rest or during motion) Latent trigger points n Do not cause spontaneous pain n Pain may be elicited with manual pressure or by needling n They may restrict range of motion n May alter motor recruitment patterns Primary trigger points n Develop independently (not from trigger point activity elsewhere) Secondary trigger points n Develop in antagonistic and protective adjacent muscles because of stress and muscle spasms n Commonly occur after eliminating a primary trigger point

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