Myofascial Pain Syndromes from Trigger Points

Myofascial pain syndrome (MPS) constitutes a substantial portion of the pain spectrum, acute and chronic, as both the primary cause of disability, and as a complication arising from other problems such as failed low back surgery, cervical whiplash, overuse, or repetitive strain syndrome. MPS is a very specific type of muscular pain, and is not to be confused with fibromyalgia. It is common after injury, resulting in so-called soft-tissue pain. MPS can be intermittent and mild, or debilitating and totally disabling. It can be acute, but it can still be effectively treated even when it has persisted for years. Pain syndromes associated with individual myofascial trigger points have been well described. [1,2••] The interactions of individual muscle myofascial trigger points, and the interaction of myofascial trigger points in functional units of muscles, especially in chronic cases, cause regional and widespread pain syndromes. Important postural consequences of dysfunctional muscle units created by myofascial trigger points affect the overall distribution and spread of pain and must be understood for treatment to be effective. For example, a round-shouldered, head-forward posture has significant implications for the position of the jaw, the state of the facial and neck muscles, the relationship of the shoulder and anterior chest muscles, and the low back. The mandible will be repositioned posteriorly, affecting the pterygoid, masseter, and temporalis muscles. Forward shoulder posture is associated with shortening of the pectoralis major and minor muscles and constant tension with their antagonist muscles, the trapezius and rhomboids. The posterior cervical muscles are overloaded, as the head is pulled back (extension of the neck even though the head is forward). The low back is usually flattened, loading the lower back muscles (quadratus lumborum, il iocostalis, and multifidi) and altering the relationships and function of the lumbosacral junction and sacroiliac joints. These changes are associated with the development and maintenance of myofascial trigger points and with the pain affecting different regions (facial and jaw pain, neck and shoulder pain, and low back pain). This example emphasizes the importance of functional muscle units in the development and spread of myofascial trigger points.