Myofascial (mi-o-fah-shell) pain is a term used to describe pain and dysfunction of skeletal muscles and their covering, called fascia. It is one of the most common causes of acute and chronic pain. Because there are over 500 separate skeletal muscles in the human body and, together with their fascia (covering tissue), muscles comprise co codamol the single largest organ system of the body, nearly everyone suffers from myofascial pain to some extent from time to time. Myofascial pain is one of the most treatable pain-producing conditions and may account for up to 75% of all physician office visits, but unfortunately it is a condition that few medical doctors are trained to properly diagnose or treat adequately.
Myofascial pain is generally localized or regional pain, usually appearing in one area of the body and involving only one or a few muscle groups. It is characterized by the finding of trigger points (TrPs) in the affected muscles. Trigger points are spots of hyperirritability usually found within a taut band of skeletal muscle or in the muscle’s fascia that are exquisitely painful when pressed and may cause local or referred pain in a pattern that is characteristic of the muscle in which they are found. TrPs may be latent or active. An active TrP is always tender, prevents full lengthening of the muscle, weakens the muscle, usually refers pain on direct compression, mediates a local twitch response of the muscle fibers when adequately stimulated, and often produces specific referred autonomic phenomena, generally in its pain reference zone. A latent TrP does not cause pain during normal activities, but is tender when touched and can become activated when the muscle it is in is strained or overly fatigued or raumatized. Most muscles of the body have specific locations were TrPs may be found on physical examination and every TrP has a characteristic pattern of pain referral. Myofascial pain is rarely completely symmetrical on both sides of the body.
The referred pain of myofascial TrPs is usually dull and aching, often deep, with intensity varying from low-grade discomfort to severe and incapacitating torture. Myofascial pain may occur at rest or only in motion. The referred pain can usually be elicited or increased in intensity by digital pressure on the associated TrP or by penetrating the TrP precisely with a needle. Generally, the more hyperirritable the TrP, the more intense and constant is the referred pain, and the more extensive its distribution. The severity and extent of the referred pain depends on the degree of hyperirritability of the TrP, not on the size of the muscle. TrPs in very small and obscure muscles can be just as painful as those in large muscles.
TrPs can also cause symptoms other than pain. Autonomic symptoms in the pain referral zone caused by TrPs may include localized vasoconstriction, sweating, lacrimation (tears), coryza (nasal discharge), salivation, and pilomotor activity (goose bumps). Proprioceptive disturbances caused by TrPs may include imbalance, dizziness, tinnitus, and distorted perception of the weight of objects lifted in the hands.
TrPs are activated directly by acute overload, overwork fatigue, direct trauma, and by chilling. They can be indirectly activated by visceral disease, arthritic joints, and emotional distress.
Some other terms that are frequently used as synonyms for myofascial pain are “myalgia” and “myoitis” or “fasciitis” or “myofasciitis.” Myalgia simply means muscle aching and is used more correctly to indicate diffusely aching muscles due to systemic disease or viral infection. Myoitis, fasciitis, and myofasciitis all refer to inflammation in the muscle, its fascia, or both, respectively. Although these terms are frequently tossed around as synonyms for myofascial pain, they are technically different. Of particular concern are the “itis” terms, because they all suggest that the patient’s pain is the result of some type of inflammatory process and, therefore, should respond to treatment with antiinflammatories. But most myofascial pain is pain without inflammation and will not be alleviated by antiinflammatory medications such as NSAIDs or corticosteroids, which can have serious adverse effects when used inappropriately for a long period or in large doses. Myofascial pain is also different from fibromyalgia and myofascial TrPs are also different from the tender points associated with fibromyalgia — but more on that later.
NOTE: The most comprehensive books on myofascial pain, trigger point locations and referral patterns, and treatment of myofascial pain syndromes are: Myofascial Pain and Dysfunction: The Trigger Point Manual, Vols. 1 & 2 by Drs. J. Travell and D. Simons and published by Wilkins & Wilkins, New York, NY.
It is frequently difficult to determine the exact cause of myofascial pain, but it can be the result of a traumatic injury to the muscle resulting from a motor vehicle accident, or over exertion of the muscle during recreational sports or physical activities, or repetitive strain from sports or work activities. Common sites of myofascial pain include muscles of the head (especially around the jaw joints), neck, shoulders, and back. A patient with symptoms of myofascial pain should be screened by a physician who specializes in treating musculoskeletal pain problems (frequently physiatrists or orthopods) so that he can be appropriately referred for treatment — usually to a qualified physical therapist who has experience in treating myofascial pain, not just joint and mobility problems.
The key to treating myofascial pain is to (1) properly identify active and latent TrPs and determine the perpetuating factors — frequently poor posture or movement dysfunctions; (2) de-activate the active TrPs and carefully stretch tight and shortened muscle; and (3) correct or remediate the underlying postural and movement dysfunctions. Because stress-related activation of the sympathetic nervous system and muscle bracing frequently play a significant role in maintaining active TrPs and myofascial pain syndromes, training in physiological relaxation and stress reduction techniques can play a critical role in treatment.
A very powerful technique in examining the functioning of groups of muscles together in movement is multiple-channel surface electromyography (sEMG), [GOTO: sEMG-assisted neuromuscular retraining] which measures the electrical activity generated by muscle movement with small electrodes taped to the skin over the muscle being examined. With a multiple-channel sEMG system, it is possible to examine a number of muscles that normally work together to accomplish a particular movement (i.e., a myotactic unit). A common finding in myofascial pain patients is that painful movements are characterized by muscles that are not functioning properly and fatigue rapidly. Often the particular muscle that should be the primary mover within a particular myotactic unit is underactive as a result of an active TrP and other muscles in the unit now are forced to do more work to compensate and, because they are not designed to carry the primary load, they become easily fatigued and painful. Frequently as these secondary muscles are forced to do more and more of the work for that particular myotactic unit, they become traumatized and develop their own “satellite” TrPs. Since a muscle that is a helper in one myotactic unit may be a primary mover in another, the development of satellite TrPs can rapidly spread the pain from a simple localized injury into a more complex regional myofascial pain syndrome affecting may different movements and activiities. sEMG is a very useful tool in sorting this type of pain problem out.