Trigger point
Encyclopedia
Trigger points, also known as trigger sites or muscle knots, are described as hyperirritable
spots in skeletal muscle
that are associated with palpable nodules
in taut bands of muscle fibers. Trigger point practitioners believe that palpable
nodules are small contraction knots and a common cause of pain
. Compression of a trigger point may elicit local tenderness, referred pain
, or local twitch response. The local twitch response is not the same as a muscle spasm. This is because a muscle spasm refers to the entire muscle contracting whereas the local twitch response also refers to the entire muscle but only involves a small twitch, no contraction.
The trigger point model states that unexplained pain frequently radiates from these points of local tenderness to broader areas, sometimes distant from the trigger point itself. Practitioners claim to have identified reliable referred pain
patterns, allowing practitioners to associate pain in one location with trigger points elsewhere. Many practitioners of chiropractic
and massage therapy find the model useful, but the medical community at large has not embraced trigger point therapy. There is no consistent methodology for diagnosis
of trigger points and a dearth of theory to explain how they arise and why they produce specific patterns of referred pain.
to describe a clinical finding with the following characteristics:
Practitioners do not necessarily agree on what constitutes a trigger point.
A study by Gerwin et al. found that independent examiners were generally able to identify myofascial trigger points (MTrP), but only with sufficient training and agreement on the definition and features of MTrP's. They said:
A 2007 review of diagnostic criteria used in studies of trigger points concluded that
concept (myofascial referring to the combination of muscle
and fascia
). This is described as a focal hyperirritability in muscle that can strongly modulate central nervous system
functions. Travell and followers distinguish this from fibromyalgia
, which is characterized by widespread pain and tenderness and is described as a central augmentation of nociception
giving rise to deep tissue tenderness that includes muscles.
Studies estimate that in 75–95 percent of cases, myofascial pain is a primary cause of regional pain. Myofascial pain is associated with muscle tenderness that arises from trigger points, focal points of tenderness, a few millimeters in diameter, found at multiple sites in a muscle and the fascia of muscle tissue. Biopsy tests found that trigger points were hyperirritable and electrically active muscle spindle
s in general muscle tissue.
There are a few more than 620 potential trigger points possible in human muscles. These trigger points, when they become active or latent, show up in the same places in muscles in every person. That is, trigger point maps can be made that are accurate for everyone.
An active trigger point is one that actively refers pain either locally or to another location (most trigger points refer pain elsewhere in the body along nerve pathways). A latent trigger point is one that exists, but does not yet refer pain actively, but may do so when pressure or strain is applied to the myoskeletal structure containing the trigger point. Latent trigger points can influence muscle activation patterns, which can result in poorer muscle coordination and balance. Active and latent trigger points are also known as "Yipe" points, for obvious reasons.
A key trigger point is one that has a pain referral pattern along a nerve pathway that activates a latent trigger point on the pathway, or creates it. A satellite trigger point is one which is activated by a key trigger point. Successfully treating the key trigger point often will resolve the satellite and return it from being active to latent, or completely treating it too.
In contrast, a primary trigger point in many cases will biomechanically activate a secondary trigger point in another structure. Treating the primary trigger point does not treat the secondary trigger point.
), homeostatic
imbalances, direct trauma to the region, accident trauma (such as a car accident which stresses many muscles and causes instant trigger points) radiculopathy
, infections and health issues such as smoking
.
Trigger points form only in muscles. They form as a local contraction in a small number of muscle fibers in a larger muscle or muscle bundle. These in turn can pull on tendons and ligaments associated with the muscle and can cause pain deep within a joint where there are no muscles. When muscle fibers contract, they use biochemical energy, and depletion of these biochemicals leads to accumulation of fatigue toxins such as lactic acid. The tightened muscle fibers constrict capillaries and prevent them from carrying off the fatigue toxins to the body's recycling system (liver and kidneys) . The buildup of these toxins in a muscle bundle or muscle feels like a tight muscle—a slippery elongate bundle.
When trigger points are present in muscles there is often pain and weakness in the associated structures. These pain patterns in muscles follow specific nerve pathways and have been readily mapped to allow for identification of the causative pain factor. Many trigger points have pain patterns that overlap, and some create reciprocal cyclic relationships that need to be treated extensively to remove them.
A 2009 review of nine studies examining the reliability of trigger point diagnosis found that physical examination could not be recommended as reliable for the diagnosis of trigger points.
Usually there is a taut band in muscles containing trigger points, and a hard nodule can be felt. Often a twitch response can be felt in the muscle by running your finger perpendicular to the muscle's direction; this twitch response often activates the "all or nothing" response in a muscle that causes it to contract. Pressing on an affected muscle can often refer pain. Clusters of trigger points are not uncommon in some of the larger muscles, such as the gluteus group (gluteus maximus
, gluteus medius
, and gluteus minimus
). Often there is a heat differential in the local area of a trigger point, and many practitioners can sense that. In 2007, a paper was presented describing images of trigger points taken by modified MRI.
(MRE) imaging of the taut band of an MTP in an upper trapezius muscle
may present a convincing demonstration of the cause of MTP symptoms. MRE is a modification of existing magnetic resonance imaging
equipment to image stress produced by adjacent tissues with different degrees of tension. This report presents an MRE image of the taut band that shows the V-shaped signature of the increased tension compared with surrounding tissues. Results were all consistent with the concept that taut bands are detectable and quantifiable with MRE imaging. The findings in the subjects suggest that the stiffness of the taut bands in patients with myofascial pain may be 50% greater than that of the surrounding muscle tissue. The findings suggest that MRE can quantitate asymmetries in muscle tone that could previously only be identified subjectively by examination.
In the study by Shah and associates, they have shown the feasibility of continuous, in vivo recovery of small molecules from soft tissue without harmful effects. With this technique, they have been able to investigate the biochemical milieu of muscle in subjects with active, latent, or absent myofascial trigger points (MTrPs) and to contrast this with that of the noninvolved muscle.
In a June 2000 review, Chang-Zern Hong correlates the MTrP "tender points" to acupunctural "ah shi" ("Oh Yes!") points, and the "local twitch response" to acupuncture's "de qi" ("needle sensation"), based on a 1977 paper by Melzack et al. Peter Dorsher comments on a strong correlation between the locations of trigger points and classical acupuncture
points, finding that 92% of the 255 trigger points correspond to acupuncture points, including 79.5% with similar pain indications.
(deep pressure as in Bonnie Prudden
's approach, massage
or tapotement
as in Dr. Griner's approach), mechanical vibration
, pulsed ultrasound
, electrostimulation, ischemic compression
, injection (see below), dry-needling
, "spray-and-stretch" using a cooling (vapocoolant) spray, Low Level Laser Therapy
and stretching
techniques that invoke reciprocal inhibition within the musculoskeletal system. Practitioners use elbows, feet or various tools to direct pressure directly upon the trigger point, to save their hands.
A successful treatment protocol relies on identifying trigger points, resolving them and, if all trigger points have been deactivated, elongating the structures affected along their natural range of motion and length. In the case of muscles, which is where most treatment occurs, this involves stretching the muscle using combinations of passive, active, active isolated (AIS), muscle energy technique
s (MET), and proprioceptive neuromuscular facilitation
(PNF) stretching to be effective. Fascia
surrounding muscles should also be treated, possibly with myofascial release
, to elongate and resolve strain patterns, otherwise muscles will simply be returned to positions where trigger points are likely to re-develop.
The results of manual therapy are related to the skill level of the therapist. If trigger points are pressed too short a time, they may activate or remain active; if pressed too long or hard, they may be irritated or the muscle may be bruised, resulting in pain in the area treated. This bruising may last for a 1–3 days after treatment, and may feel like, but is not similar to, delayed onset muscle soreness
(DOMS), the pain felt days after overexerting muscles. Pain is also common after a massage if the practitioner uses pressure on unnoticed latent or active trigger points, or is not skilled in myofascial trigger point therapy.
Evidence based medicine researchers concluded as of 2001 that evidence for the usefulness of trigger points in the diagnosis of fibromyalgia
is thin. More recently, an association has been made between fibromyalgia tender points and active trigger points.
s such as procaine hydrochloride (Novocain), steroids, and botulinum toxin
provide more immediate relief and can be effective when other methods fail. A low concentration, short acting local anesthetic such as procaine 0.5% without steroids or adrenalin is recommended. High concentrations or long acting local anesthetics as well as epinephrine
can cause muscle necrosis
, while use of steroids can cause tissue damage. Dry needling can be just as effective but causes more post-injection soreness. Botulinum toxin
is rarely indicated.
Despite the concerns about long acting agents, a mixture of lidocaine and marcaine is often used. A mixture of 1 part 2% lidocaine
with 3 parts 0.5% bupivacaine
(trade name:Marcaine) provides 0.5% lidocaine and 0.375% bupivacaine. This has the advantages of immediate anesthesia with lidocaine during injection to minimize injection pain while providing a longer duration of action with a lowered concentration of bupivacaine.
Health insurance companies in the US such as Blue Cross, Medica
, and HealthPartners
began covering trigger point injections in 2005.
s and poorly administered treatment (particularly injections) may lead to kidney damage. Likewise, treating the masseter muscle
may damage the salivary glands superficial
to this muscle. Furthermore, some experts believe trigger points may develop as a protective measure against unstable joint
s.
, London, in the 1930s and, independently, by Michael Gutstein in Berlin and Michael Kelly in Australia. The latter two workers continued to publish into the 1950s and 1960s. Kellgren conducted experiments in which he injected hypertonic saline into healthy volunteers and showed that this gave rise to zones of referred extremity pain.
Today, much treatment of trigger points and their pain complexes are handled by myofascial trigger point therapists, massage therapists, physical therapists, osteopathic physicians (DOs)
, occupational therapist
s, myotherapists
, Certified Athletic Trainer some naturopaths, chiropractors
, dentists and acupuncturists
, and other hands-on somatic
practitioners who have had experience or training in the field of neuromuscular therapy
(NMT).
, who was responsible for the most detailed and important work. Her work treating US President John F. Kennedy's
back pain was so successful that she was asked to be the first female Personal Physician to the President. She published more than 40 papers between 1942 and 1990 and in 1983 the first volume of The Trigger Point Manual appeared; this was followed by the second volume in 1992. In her later years Travell collaborated extensively with her colleague David Simons. A third edition is has been published by Simons and his wife, both of whom have survived Travell.
The trigger point concept remains unknown to most doctors and is not generally taught in allopathic (MD) medical school curricula. Among MD
s, typically only physiatrists (physicians specializing in physical medicine and rehabilitation) are well versed in trigger point diagnosis and therapy. Osteopathic medical schools, however, include trigger points in their Osteopathic manipulative medicine
training, and DO
s treat trigger points in clinical practice. Other health professionals, such as physiotherapists, chiropractors, acupuncturists, massage therapists and structural integrators are also aware of these ideas and many of them make use of trigger points in their clinical work as well.
Travell and Simons' seminal work on the subject, Myofascial Pain and Dysfunction: The Trigger Point Manual, states the following:
Irritability
Irritability is an excessive response to stimuli. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli; It is usually used to refer to anger or frustration....
spots in skeletal muscle
Skeletal muscle
Skeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...
that are associated with palpable nodules
Nodule (medicine)
For use of the term nodule in dermatology, see Nodule In medicine, a nodule refers to a relatively hard, roughly spherical abnormal structure....
in taut bands of muscle fibers. Trigger point practitioners believe that palpable
Palpation
Palpation is used as part of a physical examination in which an object is felt to determine its size, shape, firmness, or location...
nodules are small contraction knots and a common cause of pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
. Compression of a trigger point may elicit local tenderness, referred pain
Referred pain
Referred pain is pain perceived at a location other than the site of the painful stimulus. An example is the case of ischemia brought on by a myocardial infarction , where pain is often felt in the neck, shoulders, and back rather than in the chest, the site of the injury...
, or local twitch response. The local twitch response is not the same as a muscle spasm. This is because a muscle spasm refers to the entire muscle contracting whereas the local twitch response also refers to the entire muscle but only involves a small twitch, no contraction.
The trigger point model states that unexplained pain frequently radiates from these points of local tenderness to broader areas, sometimes distant from the trigger point itself. Practitioners claim to have identified reliable referred pain
Referred pain
Referred pain is pain perceived at a location other than the site of the painful stimulus. An example is the case of ischemia brought on by a myocardial infarction , where pain is often felt in the neck, shoulders, and back rather than in the chest, the site of the injury...
patterns, allowing practitioners to associate pain in one location with trigger points elsewhere. Many practitioners of chiropractic
Chiropractic
Chiropractic is a health care profession concerned with the diagnosis, treatment and prevention of disorders of the neuromusculoskeletal system and the effects of these disorders on general health. It is generally categorized as complementary and alternative medicine...
and massage therapy find the model useful, but the medical community at large has not embraced trigger point therapy. There is no consistent methodology for diagnosis
Diagnosis
Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...
of trigger points and a dearth of theory to explain how they arise and why they produce specific patterns of referred pain.
Definition
The term "trigger point" was coined in 1942 by Dr. Janet TravellJanet G. Travell
Dr. Janet Graeme Travell, M.D. was an American physician and medical researcher. She was born in 1901 to Willard and Janet Davidson Travell. Heavily influenced by her father's profession of physician, Travell made the decision to pursue a career in the medical field. In 1929, Janet married John...
to describe a clinical finding with the following characteristics:
- Pain related to a discrete, irritable point in skeletal muscle or fasciaFasciaA fascia is a layer of fibrous tissue that permeates the human body. A fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding those structures together in much the same manner as plastic wrap can be used to hold the contents of sandwiches...
, not caused by acute local traumaPhysical traumaTrauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...
, inflammationInflammationInflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
, degenerationDegeneration (medical)Degeneration is deterioration in the medical sense. Generally, it is the change from a higher to a lower form. More specifically, it is the change of tissue to a lower or less functionally active form....
, neoplasm or infectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
. - The painful point can be felt as a nodule or band in the muscle, and a twitch response can be elicited on stimulation of the trigger point.
- PalpationPalpationPalpation is used as part of a physical examination in which an object is felt to determine its size, shape, firmness, or location...
of the trigger point reproduces the patient's complaint of pain, and the pain radiates in a distribution typical of the specific muscle harboring the trigger point. - The pain cannot be explained by findings on neurological examinationNeurological examinationA neurological examination is the assessment of sensory neuron and motor responses, especially reflexes, to determine whether the nervous system is impaired...
.
Practitioners do not necessarily agree on what constitutes a trigger point.
A study by Gerwin et al. found that independent examiners were generally able to identify myofascial trigger points (MTrP), but only with sufficient training and agreement on the definition and features of MTrP's. They said:
- Three previous studies (Nice et al., 1992; Wolfe et al., 1992; Njoo and Van der Does, 1994) have examined this problem, and none of them could establish the reliability of MTrP examination in all of its major manifestations. ... The present study shows that four examiners can achieve statistically significant agreement, at times almost perfect agreement, about the presence or absence of five major features of the MTrP and on the presence or absence of the TrP, whether it be latent or active. This establishes the MTrP as a reliable clinical sign. The present study also shows that these features are identified with greater or lesser reliability depending on the specific feature and the specific muscle being examined. ... A training period was found to be essential in order to achieve these results.
A 2007 review of diagnostic criteria used in studies of trigger points concluded that
- there is as yet limited consensus on case definition in respect of MTrP pain syndrome. Further research is needed to test the reliability and validity of diagnostic criteria. Until reliable diagnostic criteria have been established, there is a need for greater transparency in research papers on how a case of MTrP pain syndrome is defined, and claims for effective interventions in treating the condition should be viewed with caution.
Myofascial pain syndrome
The main innovation of Travell's work was the introduction of the myofascial pain syndromeMyofascial pain syndrome
Myofascial pain syndrome , also known as chronic myofascial pain , is a syndrome characterized by chronic pain caused by multiple trigger points and fascial constrictions...
concept (myofascial referring to the combination of muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
and fascia
Fascia
A fascia is a layer of fibrous tissue that permeates the human body. A fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding those structures together in much the same manner as plastic wrap can be used to hold the contents of sandwiches...
). This is described as a focal hyperirritability in muscle that can strongly modulate central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
functions. Travell and followers distinguish this from fibromyalgia
Fibromyalgia
Fibromyalgia is a medical disorder characterized by chronic widespread pain and allodynia, a heightened and painful response to pressure. It is an example of a diagnosis of exclusion...
, which is characterized by widespread pain and tenderness and is described as a central augmentation of nociception
Nociception
Nociception is defined as "the neural processes of encoding and processing noxious stimuli." It is the afferent activity produced in the peripheral and central nervous system by stimuli that have the potential to damage tissue...
giving rise to deep tissue tenderness that includes muscles.
Studies estimate that in 75–95 percent of cases, myofascial pain is a primary cause of regional pain. Myofascial pain is associated with muscle tenderness that arises from trigger points, focal points of tenderness, a few millimeters in diameter, found at multiple sites in a muscle and the fascia of muscle tissue. Biopsy tests found that trigger points were hyperirritable and electrically active muscle spindle
Muscle spindle
Muscle spindles are sensory receptors within the belly of a muscle, which primarily detect changes in the length of this muscle. They convey length information to the central nervous system via sensory neurons. This information can be processed by the brain to determine the position of body parts...
s in general muscle tissue.
Qualities of trigger points
Trigger points have a number of qualities. They may be classified as potential, active/latent and also as key/satellites and primary/secondary.There are a few more than 620 potential trigger points possible in human muscles. These trigger points, when they become active or latent, show up in the same places in muscles in every person. That is, trigger point maps can be made that are accurate for everyone.
An active trigger point is one that actively refers pain either locally or to another location (most trigger points refer pain elsewhere in the body along nerve pathways). A latent trigger point is one that exists, but does not yet refer pain actively, but may do so when pressure or strain is applied to the myoskeletal structure containing the trigger point. Latent trigger points can influence muscle activation patterns, which can result in poorer muscle coordination and balance. Active and latent trigger points are also known as "Yipe" points, for obvious reasons.
A key trigger point is one that has a pain referral pattern along a nerve pathway that activates a latent trigger point on the pathway, or creates it. A satellite trigger point is one which is activated by a key trigger point. Successfully treating the key trigger point often will resolve the satellite and return it from being active to latent, or completely treating it too.
In contrast, a primary trigger point in many cases will biomechanically activate a secondary trigger point in another structure. Treating the primary trigger point does not treat the secondary trigger point.
Potential causes of trigger points
Activation of trigger points may be caused by a number of factors, including acute or chronic muscle overload, activation by other trigger points (key/satellite, primary/secondary), disease, psychological distress (via systemic inflammationInflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
), homeostatic
Homeostasis
Homeostasis is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature or pH...
imbalances, direct trauma to the region, accident trauma (such as a car accident which stresses many muscles and causes instant trigger points) radiculopathy
Radiculopathy
Radiculopathy is not a specific condition, but rather a description of a problem in which one or more nerves are affected and do not work properly . The emphasis is on the nerve root...
, infections and health issues such as smoking
Smoking
Smoking is a practice in which a substance, most commonly tobacco or cannabis, is burned and the smoke is tasted or inhaled. This is primarily practised as a route of administration for recreational drug use, as combustion releases the active substances in drugs such as nicotine and makes them...
.
Trigger points form only in muscles. They form as a local contraction in a small number of muscle fibers in a larger muscle or muscle bundle. These in turn can pull on tendons and ligaments associated with the muscle and can cause pain deep within a joint where there are no muscles. When muscle fibers contract, they use biochemical energy, and depletion of these biochemicals leads to accumulation of fatigue toxins such as lactic acid. The tightened muscle fibers constrict capillaries and prevent them from carrying off the fatigue toxins to the body's recycling system (liver and kidneys) . The buildup of these toxins in a muscle bundle or muscle feels like a tight muscle—a slippery elongate bundle.
When trigger points are present in muscles there is often pain and weakness in the associated structures. These pain patterns in muscles follow specific nerve pathways and have been readily mapped to allow for identification of the causative pain factor. Many trigger points have pain patterns that overlap, and some create reciprocal cyclic relationships that need to be treated extensively to remove them.
Diagnosis of trigger points
Trigger points are diagnosed by examining signs, symptoms, pain patterns and manual palpation.A 2009 review of nine studies examining the reliability of trigger point diagnosis found that physical examination could not be recommended as reliable for the diagnosis of trigger points.
Usually there is a taut band in muscles containing trigger points, and a hard nodule can be felt. Often a twitch response can be felt in the muscle by running your finger perpendicular to the muscle's direction; this twitch response often activates the "all or nothing" response in a muscle that causes it to contract. Pressing on an affected muscle can often refer pain. Clusters of trigger points are not uncommon in some of the larger muscles, such as the gluteus group (gluteus maximus
Gluteus maximus muscle
The gluteus maximus is the largest and most superficial of the three gluteal muscles...
, gluteus medius
Gluteus medius muscle
The gluteus medius , one of the three gluteal muscles, is a broad, thick, radiating muscle, situated on the outer surface of the pelvis....
, and gluteus minimus
Gluteus minimus muscle
The gluteus minimus , the smallest of the three gluteal muscles, is situated immediately beneath the gluteus medius.-Origin and insertion:...
). Often there is a heat differential in the local area of a trigger point, and many practitioners can sense that. In 2007, a paper was presented describing images of trigger points taken by modified MRI.
Misdiagnosis of pain
The misdiagnosis of pain is the most important issue taken up by Travell and Simons. Referred pain from trigger points mimics the symptoms of a very long list of common maladies, but physicians, in weighing all the possible causes for a given condition, rarely consider a myofascial source. The study of trigger points has not historically been part of medical education. Travell and Simons hold that most of the common everyday pain is caused by myofascial trigger points and that ignorance of that basic concept could inevitably lead to false diagnoses and the ultimate failure to deal effectively with pain.Demonstration and identification of myofascial trigger points
A 2008 review in Archives of Physical Medicine and Rehabilitation of two recent studies concludes they present groundbreaking findings that can reduce some of the controversy surrounding the cause and identification of myofascial trigger points (MTPs). The study by Chen on the use of magnetic resonance elastographyMagnetic resonance elastography
Magnetic resonance elastography is a medical imaging technique that images propagating mechanical waves using MRI. It non-invasively measures the stiffness of biological tissues. Pathological tissues are often harder than the surrounding normal tissue...
(MRE) imaging of the taut band of an MTP in an upper trapezius muscle
Trapezius muscle
In human anatomy, the trapezius is a large superficial muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae and laterally to the spine of the scapula...
may present a convincing demonstration of the cause of MTP symptoms. MRE is a modification of existing magnetic resonance imaging
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
equipment to image stress produced by adjacent tissues with different degrees of tension. This report presents an MRE image of the taut band that shows the V-shaped signature of the increased tension compared with surrounding tissues. Results were all consistent with the concept that taut bands are detectable and quantifiable with MRE imaging. The findings in the subjects suggest that the stiffness of the taut bands in patients with myofascial pain may be 50% greater than that of the surrounding muscle tissue. The findings suggest that MRE can quantitate asymmetries in muscle tone that could previously only be identified subjectively by examination.
In the study by Shah and associates, they have shown the feasibility of continuous, in vivo recovery of small molecules from soft tissue without harmful effects. With this technique, they have been able to investigate the biochemical milieu of muscle in subjects with active, latent, or absent myofascial trigger points (MTrPs) and to contrast this with that of the noninvolved muscle.
In a June 2000 review, Chang-Zern Hong correlates the MTrP "tender points" to acupunctural "ah shi" ("Oh Yes!") points, and the "local twitch response" to acupuncture's "de qi" ("needle sensation"), based on a 1977 paper by Melzack et al. Peter Dorsher comments on a strong correlation between the locations of trigger points and classical acupuncture
Acupuncture
Acupuncture is a type of alternative medicine that treats patients by insertion and manipulation of solid, generally thin needles in the body....
points, finding that 92% of the 255 trigger points correspond to acupuncture points, including 79.5% with similar pain indications.
Treatment
Myofascial Trigger Point therapists may use myotherapyMyotherapy
Myotherapy is a form of manual medicine focusing on the diagnosis, treatment and management of musculoskeletal pain.- Definition :Myotherapy is a branch of manual medicine which focuses on the treatment and management of musculoskeletal pain...
(deep pressure as in Bonnie Prudden
Bonnie Prudden
Bonnie Prudden was a leading American rock climber in the 1940s and 1950s, with 30 documented first ascents to her credit in New York's Shawangunks mountains. Along with Hans Kraus, she was a pioneering advocate of physical fitness and later developed a form of trigger point therapy called...
's approach, massage
Massage
Massage is the manipulation of superficial and deeper layers of muscle and connective tissue to enhance function, aid in the healing process, and promote relaxation and well-being. The word comes from the French massage "friction of kneading", or from Arabic massa meaning "to touch, feel or handle"...
or tapotement
Tapotement
Tapotement is a specific technique used in Swedish massage. It is a rhythmic percussion, most frequently administered with the edge of the hand, a cupped hand or the tips of the fingers...
as in Dr. Griner's approach), mechanical vibration
Vibration
Vibration refers to mechanical oscillations about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road.Vibration is occasionally "desirable"...
, pulsed ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
, electrostimulation, ischemic compression
Ischemic compression
Ischemic compression is a therapy technique used in physical therapy, where blockage of blood in an area of the body is deliberately made, so that a resurgence of local blood flow will occur upon release....
, injection (see below), dry-needling
Dry needling
Dry needling is the use of solid filiform needles for therapy of muscle pain, sometimes also known as intramuscular stimulation. The needles are similar to acupuncture needles. Dry needling contrasts with the use of a hollow hypodermic needle to inject substances such as saline solution, botox or...
, "spray-and-stretch" using a cooling (vapocoolant) spray, Low Level Laser Therapy
Low level laser therapy
Low-level laser therapy is a medical and veterinary treatment that uses low-level lasers or light-emitting diodes to alter cellular function...
and stretching
Stretching
Stretching is a form of physical exercise in which a specific skeletal muscle is deliberately elongated, often by abduction from the torso, in order to improve the muscle's felt elasticity and reaffirm comfortable muscle tone. The result is a feeling of increased muscle control, flexibility and...
techniques that invoke reciprocal inhibition within the musculoskeletal system. Practitioners use elbows, feet or various tools to direct pressure directly upon the trigger point, to save their hands.
A successful treatment protocol relies on identifying trigger points, resolving them and, if all trigger points have been deactivated, elongating the structures affected along their natural range of motion and length. In the case of muscles, which is where most treatment occurs, this involves stretching the muscle using combinations of passive, active, active isolated (AIS), muscle energy technique
Muscle Energy Technique
Muscle Energy Technique is a type of osteopathic manipulative treatment used in osteopathic medicine and physical therapy . It is a form of osteopathic manipulative diagnosis and treatment in which the patient’s muscles are actively used on request, from a precisely controlled position, in a...
s (MET), and proprioceptive neuromuscular facilitation
PNF stretching
PNF stretching, or proprioceptive neuromuscular facilitation stretching, is an occupational therapy and physical therapy procedure designed in the 1940s and 1950s to rehabilitate patients with paralysis. It is often a combination of passive stretching and isometrics contractions. In the 1980s,...
(PNF) stretching to be effective. Fascia
Fascia
A fascia is a layer of fibrous tissue that permeates the human body. A fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding those structures together in much the same manner as plastic wrap can be used to hold the contents of sandwiches...
surrounding muscles should also be treated, possibly with myofascial release
Myofascial Release
The myofascial release approach is a form of soft tissue therapy used to treat somatic dysfunction and resulting pain and restriction of motion. It is a treatment described by Andrew Taylor Still, founder of osteopathy/osteopathic medicine, and his early students, which uses continual palpatory...
, to elongate and resolve strain patterns, otherwise muscles will simply be returned to positions where trigger points are likely to re-develop.
The results of manual therapy are related to the skill level of the therapist. If trigger points are pressed too short a time, they may activate or remain active; if pressed too long or hard, they may be irritated or the muscle may be bruised, resulting in pain in the area treated. This bruising may last for a 1–3 days after treatment, and may feel like, but is not similar to, delayed onset muscle soreness
Delayed onset muscle soreness
Delayed onset muscle soreness , also called muscle fever, is the pain and stiffness felt in muscles several hours to days after unaccustomed or strenuous exercise. The soreness is felt most strongly 24 to 72 hours after the exercise. It is caused by eccentric exercise...
(DOMS), the pain felt days after overexerting muscles. Pain is also common after a massage if the practitioner uses pressure on unnoticed latent or active trigger points, or is not skilled in myofascial trigger point therapy.
Evidence based medicine researchers concluded as of 2001 that evidence for the usefulness of trigger points in the diagnosis of fibromyalgia
Fibromyalgia
Fibromyalgia is a medical disorder characterized by chronic widespread pain and allodynia, a heightened and painful response to pressure. It is an example of a diagnosis of exclusion...
is thin. More recently, an association has been made between fibromyalgia tender points and active trigger points.
Injection
Injections, including saline, local anestheticLocal anesthetic
A local anesthetic is a drug that causes reversible local anesthesia, generally for the aim of having local analgesic effect, that is, inducing absence of pain sensation, although other local senses are often affected as well...
s such as procaine hydrochloride (Novocain), steroids, and botulinum toxin
Botulinum toxin
Botulinum toxin is a protein produced by the bacterium Clostridium botulinum, and is considered the most powerful neurotoxin ever discovered. Botulinum toxin causes Botulism poisoning, a serious and life-threatening illness in humans and animals...
provide more immediate relief and can be effective when other methods fail. A low concentration, short acting local anesthetic such as procaine 0.5% without steroids or adrenalin is recommended. High concentrations or long acting local anesthetics as well as epinephrine
Epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...
can cause muscle necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
, while use of steroids can cause tissue damage. Dry needling can be just as effective but causes more post-injection soreness. Botulinum toxin
Botulinum toxin
Botulinum toxin is a protein produced by the bacterium Clostridium botulinum, and is considered the most powerful neurotoxin ever discovered. Botulinum toxin causes Botulism poisoning, a serious and life-threatening illness in humans and animals...
is rarely indicated.
Despite the concerns about long acting agents, a mixture of lidocaine and marcaine is often used. A mixture of 1 part 2% lidocaine
Lidocaine
Lidocaine , Xylocaine, or lignocaine is a common local anesthetic and antiarrhythmic drug. Lidocaine is used topically to relieve itching, burning and pain from skin inflammations, injected as a dental anesthetic or as a local anesthetic for minor surgery.- History :Lidocaine, the first amino...
with 3 parts 0.5% bupivacaine
Bupivacaine
Bupivacaine is a local anaesthetic drug belonging to the amino amide group. AstraZeneca commonly markets it under various trade names, including Marcain, Marcaine, Sensorcaine and Vivacaine.-Indications:...
(trade name:Marcaine) provides 0.5% lidocaine and 0.375% bupivacaine. This has the advantages of immediate anesthesia with lidocaine during injection to minimize injection pain while providing a longer duration of action with a lowered concentration of bupivacaine.
Health insurance companies in the US such as Blue Cross, Medica
MEDICA
MEDICA is a French private health group specialized in the exploitation of global care facilities for dependent persons.-Activities:The MEDICA group operates in the sector of nursing homes for elderly dependent persons, in France and Italy, and in the health sector, with medical units of follow-up...
, and HealthPartners
HealthPartners
HealthPartners is an integrated, nonprofit heath care provider located in Bloomington, Minnesota, offering a number of different heath care plans. It is the largest consumer-governed, nonprofit health care organization in the United States. - History :...
began covering trigger point injections in 2005.
Self-treatment
There are a number of ways to self-treat trigger points and these methods are described in numerous texts. Underlying any attempts at self-treatment should be a working knowledge of the area to be treated, especially with regard to the musculature, nerves, glands and vessels.Risks
Treatment, whether by self or by a professional, has some inherent dangers. It may lead to damage of soft tissue and other organs. The trigger points in the upper quadratus lumborum, for instance, are very close to the kidneyKidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s and poorly administered treatment (particularly injections) may lead to kidney damage. Likewise, treating the masseter muscle
Masseter muscle
In human anatomy, the masseter is one of the muscles of mastication.In the animal kingdom, it is particularly powerful in herbivores to facilitate chewing of plant matter.-Origin and insertion of the two heads:...
may damage the salivary glands superficial
Superficial
Superficial may refer to:*Superficial , an album by Heidi Montag*"Superficial" *The Superficial, a website devoted to celebrity gossip...
to this muscle. Furthermore, some experts believe trigger points may develop as a protective measure against unstable joint
Joint
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
s.
Research
Studies to date on the efficacy of dry needling have been inconclusive but weakly supportive, leading to plans for a larger phase III clinical trial with more statistical power.History
Trigger points have been a subject of study by a small number of doctors for several decades although this has not become part of mainstream medicine. The existence of tender areas and zones of induration in muscles has been recognized in medicine for many years and was described as muscular rheumatism or fibrositis in English; German terms included myogelose and myalgie. However, there was little agreement about what they meant. Important work was carried out by J. H. Kellgren at University College HospitalUniversity College Hospital
University College Hospital is a teaching hospital located in London, United Kingdom. It is part of the University College London Hospitals NHS Foundation Trust and is closely associated with University College London ....
, London, in the 1930s and, independently, by Michael Gutstein in Berlin and Michael Kelly in Australia. The latter two workers continued to publish into the 1950s and 1960s. Kellgren conducted experiments in which he injected hypertonic saline into healthy volunteers and showed that this gave rise to zones of referred extremity pain.
Today, much treatment of trigger points and their pain complexes are handled by myofascial trigger point therapists, massage therapists, physical therapists, osteopathic physicians (DOs)
Osteopathy
Osteopathy and osteopathic medicine are often used interchangeably for the philosophy and system of alternative medical practice first proposed by A. T. Still MD, DO in 1874....
, occupational therapist
Occupational therapist
An occupational therapist is trained in the practice of occupational therapy. The role of an occupational therapist is to work with a client to help them achieve a fulfilled and satisfied state in life through the use of "purposeful activity or interventions designed to achieve functional...
s, myotherapists
Myotherapy
Myotherapy is a form of manual medicine focusing on the diagnosis, treatment and management of musculoskeletal pain.- Definition :Myotherapy is a branch of manual medicine which focuses on the treatment and management of musculoskeletal pain...
, Certified Athletic Trainer some naturopaths, chiropractors
Chiropractic
Chiropractic is a health care profession concerned with the diagnosis, treatment and prevention of disorders of the neuromusculoskeletal system and the effects of these disorders on general health. It is generally categorized as complementary and alternative medicine...
, dentists and acupuncturists
Acupuncture
Acupuncture is a type of alternative medicine that treats patients by insertion and manipulation of solid, generally thin needles in the body....
, and other hands-on somatic
Somatic
The term somatic means 'of the body',, relating to the body. In medicine, somatic illness is bodily, not mental, illness. The term is often used in biology to refer to the cells of the body in contrast to the germ line cells which usually give rise to the gametes...
practitioners who have had experience or training in the field of neuromuscular therapy
Neuromuscular therapy
Neuromuscular therapy is a form of massage. It is distinguished from other types of massage in that a quasi-static pressure is applied to the skin with the aim of stimulating specific areas of skeletal muscle...
(NMT).
Janet G. Travell, MD
It was, however, an American physician, Janet G. TravellJanet G. Travell
Dr. Janet Graeme Travell, M.D. was an American physician and medical researcher. She was born in 1901 to Willard and Janet Davidson Travell. Heavily influenced by her father's profession of physician, Travell made the decision to pursue a career in the medical field. In 1929, Janet married John...
, who was responsible for the most detailed and important work. Her work treating US President John F. Kennedy's
John F. Kennedy
John Fitzgerald "Jack" Kennedy , often referred to by his initials JFK, was the 35th President of the United States, serving from 1961 until his assassination in 1963....
back pain was so successful that she was asked to be the first female Personal Physician to the President. She published more than 40 papers between 1942 and 1990 and in 1983 the first volume of The Trigger Point Manual appeared; this was followed by the second volume in 1992. In her later years Travell collaborated extensively with her colleague David Simons. A third edition is has been published by Simons and his wife, both of whom have survived Travell.
The trigger point concept remains unknown to most doctors and is not generally taught in allopathic (MD) medical school curricula. Among MD
Physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...
s, typically only physiatrists (physicians specializing in physical medicine and rehabilitation) are well versed in trigger point diagnosis and therapy. Osteopathic medical schools, however, include trigger points in their Osteopathic manipulative medicine
Osteopathic Manipulative Medicine
Osteopathic Manipulative Medicine is the application of the distinct osteopathic philosophy, structural diagnosis and use of Osteopathic Manipulative Technique in the diagnosis and management of the patient. OMM takes into account the physical and mental health of a patient, and how either aspect...
training, and DO
DO
DO may refer to:* Directorate of Operations, former name of the National Clandestine Service* Doctor of Osteopathic Medicine, a degree held by physicians in the United States* Dominican Republic, ISO country code: do...
s treat trigger points in clinical practice. Other health professionals, such as physiotherapists, chiropractors, acupuncturists, massage therapists and structural integrators are also aware of these ideas and many of them make use of trigger points in their clinical work as well.
Travell and Simons' seminal work on the subject, Myofascial Pain and Dysfunction: The Trigger Point Manual, states the following:
- Around 75% of pain clinic patients have a trigger point as the sole source of their pain.
- ArthritisArthritisArthritis is a form of joint disorder that involves inflammation of one or more joints....
is often cited as the cause for pain even though pain is not always concomitant with arthritis. The real culprit may be a trigger point, normally activated by a certain activity involving the muscles used in the motion, by chronically bad posture, bad mechanics, repetitive motion, structural deficiencies such as a lower limb length inequality or a small hemipelvis, or nutritional deficiencies. - The following conditions are also frequently misdiagnosed as the cause of pain when trigger points are the true cause: carpal tunnel syndromeCarpal tunnel syndromeCarpal Tunnel Syndrome is an entrapment idiopathic median neuropathy, causing paresthesia, pain, and other symptoms in the distribution of the median nerve due to its compression at the wrist in the carpal tunnel. The pathophysiology is not completely understood but can be considered compression...
, bursitisBursitisBursitis is the inflammation of one or more bursae of synovial fluid in the body. The bursae rest at the points where internal functionaries, such as muscles and tendons, slide across bone. Healthy bursae create a smooth, almost frictionless functional gliding surface making normal movement painless...
, tendinitis, angina pectoris, and sciatic symptomsSciaticaSciatica is a set of symptoms including pain that may be caused by general compression or irritation of one of five spinal nerve roots that give rise to each sciatic nerve, or by compression or irritation of the left or right or both sciatic nerves. The pain is felt in the lower back, buttock, or...
, along with many other pain problems.