Understanding Myofascial Pain
It has been estimated that
some 44 million Americans have myofascial pain problems (1). A
study from an internal medicine group practice found that 30% of
patients with pain complaints had active myofascial trigger
points (2). A report from a clinic specializing in head and neck
pain reported a myofascial etiology in 55% of cases (3).
Patients evaluated in one pain management center were found to
have a myofascial component to their pain in 95% of cases (4).
There is increasing awareness that active myofascial trigger
points often play a role in the symptoms of patients with
tension headaches (5), low back pain, neck pain (6),
temporomandibular pain (7), forearm and hand pain (8), postural
pain (9), pelvic/urogenital pain syndromes.
In interpreting the results
of prevalence studies, it is important to distinguish between
active myofascial trigger points and latent myofascial trigger
points. Latent myofascial trigger points are defined as tender
areas in muscle, in association with the other clinical features
of the trigger point (see table 1), in the absence of associated
pain syndrome. Active myofascial trigger points are associated
with a pain syndrome that is reproduced by firm palpation of the
For instance, Sola found
latent trigger points in the shoulder girdle muscles of 54% of
female and 45% of male subjects who were completely asymptomatic
There have been no
prevalence studies of myofascial pain syndromes in the context
of rheumatology practice, but it is the author's experience that
myofascial pain problems are often undiagnosed / untreated
components of pain in osteoarthritis, rheumatoid arthritis,
systemic lupus and other common rheumatic disorders.
The clinical diagnosis of
myofascial pain is critically dependent on your doctor being
aware of this diagnosis as a possible cause for some of your
pain (11). Myofascial pain syndromes may mimic a large number of
other disorders, thus there is a necessity to perform a thorough
physical examination, with appropriate investigations.
Myofascial pain characteristically presents as a dull deep
aching sensation which is aggravated by use of the involved
muscles as well as psychological stressors that cause increased
muscle tension (12). The defining clinical characteristic of
myofascial pain is the finding of a trigger point. This is a
well-defined point of focal tenderness within a muscle.
Sometimes firm palpation of this focus elicits pain in a
referred distribution that reproduces the patient’s symptoms.
Importantly, referred pain from a trigger point does not follow
a nerve root distribution (i.e. it is not dermatomal). Palpation
usually reveals a ropelike induration of the associated muscle
fibers, often referred to as the “taut band”. Sometimes,
snapping this band or needling the trigger point produces a
localized twitch response of the involved muscle. This twitch
response can only be reproducibly elicited in fairly superficial
Myofascial pain often
results from muscle injury or repetitive strain. In the current
medical climate, especially in United States, a whole array of
often expensive investigations have usually been undertaken
before the possibility of a myofascial pain diagnosis is
considered. Some patients, who already have a well-defined
cause for their musculoskeletal pain (e.g. rheumatoid
arthritis), may develop a myofascial pain syndrome that goes
unrecognized, as it is assumed that all their pain emanates from
their primary diagnosis. Myofascial pain has certain clinical
characteristics that aid in considering this diagnosis. The pain
is typically described as a deep aching sensation, often with a
feeling of stiffness in the involved area; this is sometimes
described in terms of joint stiffness. Myofascial pain is
aggravated by use of the involved muscle(s), psychological
stressors, anxiety, cold and postural imbalance. Radiation from
a trigger point may be described in terms of paresthesiae and
thus mimic the symptoms of a cervical or lumbar radiculopathy.
Muscle weakness secondary to disuse may present with symptoms
weakness, poor coordination, reduced work tolerance, fatigue and
sleep disturbance. Patients with myofascial pain involving the
neck and face muscles may experience symptoms of dizziness,
tinnitus and poor balance.
features of a myofascial trigger point:
1. Focal point of tenderness
to palpation of the involved muscle
2. Reproduction of pain
complaint by trigger point palpation (about 3 kg
3. Palpation reveals an
induration of the adjacent muscle (the “taught band”)
4. Restricted range of
movement in the involved muscle
5. Often pseudo-weakness of
the involved muscle (no atrophy)
6. Often referred pain on
continued (~5 secs) pressure over trigger point.
Common Symptoms of
A myofascial pain syndrome
may be due to just one trigger point, but more commonly there
are several trigger points responsible for any given regional
pain problem. It is not uncommon for the problem to be initiated
with a single trigger point with the subsequent development of
satellite trigger points that evolve over time due to the
mechanical imbalance resulting from reduced range of movement
and pseudo-weakness. The persistence of a trigger point may lead
to neuroplastic changes at the level of the dorsal horn which
results in amplification of the pain sensation (i.e. central
sensitization) with a tendency to spread beyond its original
boundaries (i.e. expansion of receptive fields) (13). In some
instances segmental central sensitization leads to the phenomena
of mirror image pain (i.e. pain on the opposite side of the body
in the same segmental distribution) and in other instances a
progressive spread of segmental central sensitization gives rise
to the widespread pain that characterizes fibromyalgia (14).
Low back pain
Acute low back pain has
many causes. Some are potentially serious, such as cancer
metastases, osteomyelitis, massive disk herniations (e.g. cauda
equina syndrome), vertebral fractures, pancreatic cancer and
aortic aneurysms. However the commonest cause of acute back
pain is so-called lumbosacral strain. In 95% of cases this
resolves within three months. In those cases that do not resolve
the development of a chronic low back pain syndrome is usually
accompanied by the finding of active myofascial trigger points.
Simons of describes 15 torso and pelvic muscles which may be
involved in low back pain (10). The most commonly involve muscle
group is the quadratus lumborum; pain emanating from trigger
points in these muscles is felt fin the low back with occasional
radiation in a sciatic distribution or into the testicles.
Trigger points involving the iliopsoas are also a common cause
of chronic low back pain. The typical distribution of iliopsoas
pain is a vertical band in the low back region and the upper
portion of the anterior thigh. Trigger points at the origin of
the gluteus medius from the iliac crest are common cause for low
back pain in the sacral and buttock with a referral pattern to
the outer hip region.
Neck and shoulder pain
Latent trigger points are
universal finding in many of the muscles of the posterior neck
and upper back. Active trigger points commonly involve the upper
portion of the trapezius and levator scapula. Upper trapezius
trigger points referred pain to the back of the neck and not
uncommonly to the angle of jaw. Levator scapula trigger points
cause pain at the angle of the neck and shoulder; this pain is
often described as lancinating, especially on active use of this
muscle. As many of the muscles in this area have an important
postural function they are commonly activated in office workers
and developmental problems causing spinal malalignment (e.g.
short leg syndrome, hemipelvis and scoliosis). As the upper
trapezius and levator scapulae act synergistically with several
other muscles in elevation and fixation of the scapula it is
common for a single trigger point in this region to initiating a
spread of satellite trigger points through adjacent muscles
which are part of the same functional unit.
Pain arising from disorders
of the hip joint is felt in the groin and the lower medial
aspect of the anterior thigh. This distribution is uncommon in
myofascial pain syndromes except for iliopsoas pain. The great
majority of patients complain of hip pain in fact localize their
pain to the outer aspect of the hip. In some patients this is
due to a trochanteric bursitis, but in the majority of cases it
is related to myofascial trigger points in the adjacent
muscles. By far the commonest trigger points giving rise to
outer hip pain are those in the attachments of the gluteus
medius and minimus muscles into the greater trochanter.
The pelvic floor
musculature is a common sight for myofascial trigger points.
There is increasing recognition by gynecologists and urologists
that pain syndromes described in terms of prostatitis, coccydnia,
vulvodynia and endometriosis are often accompanied by active
myofascial trigger points. One of the most commonly involved
intrapelvic muscles is the levator ani; its pain distribution is
central low buttock.
Active myofascial trigger
points in the muscles of the shoulder neck and face are a common
source of headaches (15). In many instances the headache has
the features of so-called tension headache, but there is
increasing acceptance that myofascial trigger points may
initiate classical migraine headaches or be part of a mixed
tension/migraine headache complex. For instance sterno-cleido
mastoid trigger points refer pain to the anterior face and
supraorbital area. Upper trapezius trigger points refer pain to
the vertex forehead and temple. Trigger points in the deep
cervical muscles of the neck may cause post occipital and
There is a complex
interrelationship between temporomandibular joint dysfunction
and myofascial trigger points (3) Common trigger points involved
in jaw pain syndromes are the massetters, pterygoids, upper
trapezius and upper sterno-cleido mastoid.
Upper Limb pain
The muscles attached to the
scapula are common sites for trigger points that can cause upper
limb pain (16). These included the subscapularis, infraspinatus,
teres major and serratus anterior. It is not uncommon for
trigger points in these locations to refer pain two the wrist
hand and fingers. Extension flexion injuries to the neck often
activate a trigger point in the pectoralis minor with a
radiating pain or down the ulnar side of the arm and into the
little finger. Myofascial pain syndromes of the upper limb are
often misdiagnosed as frozen shoulder, cervical radiculopathy or
thoracic outlet syndrome (10).
Lower limb pain
Trigger points in the
tensor fascia lata and ilio tibial band may be responsible for
lateral thigh pain and lateral knee pain respectively. Anterior
knee pain may result from trigger points in various components
of the quadriceps musculature. Posterior knee pain can result
from trigger points in the hamstring muscles and popliteus.
Trigger points in the anterior tibialis and the peroneus longus
muscles may cause pain in the anterior leg and lateral ankle
respectively. Myofascial pain syndromes involving these muscles
are often associated with ankle injuries or an excessively
pronated foot. Sciatica pain may be mimicked by a trigger point
in the posterior portion of the gluteus minimus muscle.
Chest and abdominal pain
intrathoracic and intra-abdominal organs are some of the
commonest problems encountered in internal medicine. For
instance, anterior chest pain is a frequent cause for the
emergency room admissions, but in the majority of patients a
myocardial infarction is not found. In some cases the chest pain
is caused by trigger points in the anterior chest wall muscles
(17). Pectoralis major trigger points cause ipsilateral
anterior chest pain with radiation down the ulnar side of the
arm – thus mimicking cardiac ischemic pain. A trigger point in
the sternalis muscle typically causes a deep substernal aching
sensation. Trigger points at the upper and lower insertions of
the rectus abdominus muscles may mimic the discomfort of gall
bladder and bladder infections respectively. It is important
to note that myofascial trigger points may accompany disorders
of intrathoracic and intra-abdominal viscera, and thus a
diagnosis of an isolated myofascial cause for symptoms should
never be made without an appropriate workup.
The precise basis for the
trigger point phenomena is still not fully understood. There is
a general agreement that electromyographic recordings from
trigger points show low voltage spontaneous activity resembling
endplate spike potentials (18). Simons envisions a myofascial
trigger point to be “a cluster of numerous microscopic loci if
intense abnormality that are scattered throughout the tender
nodule” (10). It is thought that these loci result from a focal
energy crisis (from injury or repetitive use) that results in
contraction of focal sarcomeric units due to calcium release
from the sarcoplasmic reticulum. Factors commonly cited as
predisposing to trigger point formation include deconditioning,
poor posture, repetitive mechanical stress, mechanical imbalance
(e.g. leg length inequality), joint disorders, non-restorative
sleep and vitamin deficiencies.
Here is a cartoon
of a trigger point complex seen in a longitudinal section of
muscle. The top component represents a muscle with a taut band.
The middle component represents a magnified view of the taut
band containing an active trigger point focus. The lower
component represents further magnification of the taut band and
trigger point focus showing contraction knots (contracted
sarcomere units). It is envisaged that these contraction knots
are responsible for the nodularity of the taut band.
pain syndromes usually resolve with appropriate correction of
predisposing factors and myofascial treatment (12). If the
symptoms are persistent, due to ineffective management, the
development of segmental central sensitization may lead to a
stubbornly recalcitrant pain disorder. In some such cases, the
spread of central sensitization leads to the widespread pain
syndrome of fibromyalgia.
For effective management of
myofascial pain syndromes requires attention to the following
The most critical element
in the effective management of myofascial pain syndromes is the
correction of predisposing factors (see above). These interfere
with the ability of the muscle to fully recover and are the
commonest reason for treatment failures.
The muscles involved in
myofascial pain syndromes are shortened due to the
aforementioned focal contractions of sarcomeric units. It is
thought to these focal contractions result in on prolonged ATP
consumption and that the restoration of a muscle to its full
stretch length breaks the link between the energy crisis and
contraction of sarcomeric units. Effective stretching is most
commonly achieved through the technique of spray and stretch
(20). This involves the cutaneous application, along the axis
of the muscle, of ethyl chloride spray while at the same time
passively stretching the involved muscle. Other techniques to
enhance effective stretching include trigger point to pressure
release, post isometric relaxation, reciprocal inhibition and
deep stroking massage (10)
Muscles harboring trigger
points usually become weak due to the inhibitory effects of
pain. A program of slowly progressive strengthening is essential
to restore full function and minimize the risk of recurrence and
the perpetuation of satellite trigger points.
Trigger point injections
Injection of trigger points
it generally considered to be the most effective means of direct
inactivation. A peppering technique using a fine needle to
inactivate all the foci within a trigger point locus is the
critical element of successful trigger point therapy (21).
Accurate localization of the trigger point is confirmed if a
local twitch response is obtained; however this may not be
obvious when needling deeply lying muscles. Successful
elimination of the trigger point usually results in a relaxation
of the taut band. Although dry needling is effective, the use
of a local anesthetic (1% lidocaine or 1% procaine) helps
confirm the accuracy of the injection and provides instant
gratification for patients (22). There is no evidence that the
injection of corticosteroids provides any enhanced effect. A
beneficial role for botulinum toxin in trigger point injections
has not so far been conclusively demonstrated.
Currently there is no
evidence that any form of drug treatment of men eighths
myofascial trigger points (20). NSAIDs and other analgesics
usually provide moderate symptomatic relief. Tricyclic
antidepressant drugs, which modulate pain at the central level,
are often of benefit especially in those patients with an
associated sleep disturbance. In the author’s experience,
tizanidine (a muscle relaxant which also ameliorates pain by
activating alpha 2 adrenergic receptors) is often a useful
adjunct in difficult to treat myofascial pain syndromes.
In severe myofascial pain
syndromes, that are not responding to treatment, patients often
become anxious and depressed. These mood disorders need to be
recognized and appropriately treated. Persistent muscle tension
exacerbates the pain of myofascial trigger points and can often
one be effectively managed with EMG biofeedback, cognitive
behavioral therapy and hypnotic/meditation relaxation
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