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fibromyalgia: A form of myofascial trigger points?
FibrositidFibromyalgia: A Form of Myofascial Trigger Points?
The diagnostic criteria for fibrositis and primary fibromyaigia are similar to those for myofasciai pain syndromes due to trigger points. Tender points in muscles are likely to be myofasciai trigger points; nonmuscular tender points clearly are not myofasciai trigger points, but may be areas of tenderness referred from such trigger points. Myofasciai trigger points refer pain to a distance and restrict range of motion of the muscle. They are associated with a palpable taut band that exhibits a local twitch response of the muscle, and they are responsive to treatment. Persistence of myofasciai trigger points is due to perpetuating factors that can usually be corrected. Although their number is unknown, it is likely that some patients who are diagnosed as having fibrositis/fibromyaigia have multiple myofasciai trigger points aggravated by a powerful perpetuating factor and also have a systemic disease process independent of the myofasciai trigger points. Since myofasciai pain syndromes are treatable, these patients would benefit greatly by identification and relief of the myofasciai component of their pain.
DAVID G. SIMONS, M.D. Huntington
Beach,
California
In the past, many authors have used the same term, fibrositis, to describe quite different patient populations [l]. Recently, Smythe [2], Wolfe and Cathey [3], Bennett [4], and others have adopted a definition of fibrositis that describes essentially the same patient population. Yunus et al [5] have introduced a new term, primary fibromyalgia, using less restrictive criteria to describe a similar, but larger, patient population. Travel1 and Simons [6] have used some overlapping, but additional, specific criteria to identify a much larger patient population with myofascial pain syndromes. The question arises as to whether a patient diagnosed as having fibrositis or primary fibromyalgia has only extensive multiple myofascial trigger points aggravated by severe perpetuating factors; or a separate systemic disorder that is responsible for the symptoms; or some combination of fibrositis or fibromyalgia and myofascial trigger points. To address that issue, this article reviews and compares the diagnostic criteria established for each of the three syndromes. It then considers in detail the distinction between tender points and trigger points. Finally, it illustrates how the myofascial origin of a tender point may be determined. From the Myofascial Pain Clinic, Rehabilitation Medicine Service, Veterans Administration Medical Center, Long Beach, California, and the Department of Physical Medicine and Rehabilitation, University of California, Irvine; Irvine, California. Aequests for reprints should be addressed to Dr. David G. Simons, 324 12th Street, Huntington Beach, California 92848.
September
DEFINITION OF SYNDROMES Smythe [2] in 1981 listed the diagnostic criteria for fibrositis as follows: (1) widespread aching of more than three months’ duration; (2) local tenderness at 12 of 14 specific sites; (3) skin-roll tenderness over the upper scapular region; and (4) disturbed sleep with morning fatigue and stiffness. These criteria were modified by others [3,4] as to the number of tender points and the associated clinical symptoms.
29,1988
The
American
Journal
of Yedlcine
Volume
81 (suppl3A)
93
SYMPOSIUM
TABLE
I
ON FIBROSITIS/FIBROMYALGIA-SIMONS
Diagnostic Features of Fibrositis [2,3] and Primary of Myofascial Pain Syndromes [61 Feature
Prevalence
Pain
sensitive
Skin-roll tenderness Muscle weakness Restricted range of motion Local twitch response of muscle Treatment
FibrositislFibmmyalgia
By definition, Often
or 80%
By definition, ? ? ? Nonspecific
or usually
September 29, 1986
The American
Journal
of Medlclne
[5] Compared
with Those
Myofascial Pain Syndrome Common-50%
male and female
Equal numbers of males Myofascial trigger points
recruits
and females (any number)
Muscle-specific pain patterns; if untreated becomes chronic Common Common especially with low serum folic acid levels and thyroid function inadequacy Occasionally Whenever testable Always some; depends on muscle Frequently observed: diagnostic when present Specific myofascial therapy
or more
Yunus et al [5] in 1982 described the most common symptoms in patients with primary fibromyalgia as generalized aches and pains, tiredness or fatigue, stiffness, anxiety and/or depression, and disturbed sleeping patterns. These symptoms were aggravated by cold or humid weather, fatigue (physical or mental), and physical inactivity. Characteristic physical findings included normal joints and normal muscle strength, multiple tender points (three or more), muscle spasm, tender “fibrositic nodules,” and erythema over the palpated tender points. In the Dictionary of Rheumatic Diseases [7], myofascial pain is defined as follows: “Musculoskeletal pain or aching, diffuse or local, felt anywhere in the body. It is typically deep in character with boundaries that have no apparent anatomical basis, and is often aggravated by movement.” I would further limit this definition to include only pain referred from myofascial trigger points. Travel1 and Simons [6] listed diagnostic criteria for identifying active myofascial trigger points. Patients with a myofascial pain syndrome characteristically present with a history of acute or chronic muscle strain. Their pain is localized in a pattern OFcombination of patterns characteristic of those referred by myofascial trigger points. Each muscle has its own characteristic referred pain pattern. Pain is likely to be aggravated, by prolonged immobilization and by stressful activity of involved muscles. Examination consistently reveals at least some restriction, at times severe, of the stretch range of motion in affected muscles. Careful testing reveals a degree of ratchety, “break-away” muscle weakness. A reproducible spot of exquisite tenderness (trigger point) is located within a taut, palpable band of muscle fibers. Pressure on this spot reproduces a “jump sign” response of the patient. Snapping palpation of the trigger point often produces a local twitch response of the band of muscle fibers. This response is pathognomonic of a trigger point. Likewise, reproduction of the distribution
64
Syndromes
Uncommon-4% with primary and 11% with concomitant fibrositis Predominantly female Multiple (more than seven or more than 12) tender points Widespread and chronic (more than three months)
Sex Tenderness
Sleep disorder Cold and weather
Fibromyalgia
and quality of the patients pain by pressure on, or by needling of, a tender point identifies it as a trigger point. Not all tender spots on the body are trigger points. All trigger points are tender to palpation. The distinction between active and latent trigger points is critical. Only active trigger points are responsible for a clinical report of pain by the patient [6]. On examination, latent trigger points may have all of the other characteristics of active trigger points except that latent trigger points produce no pain at rest or with muscular activity. They are tender and rarely refer pain when palpated. An understanding of the role of perpetuating factors is essential to effective management of chronic myofascial pain syndromes. In the absence of perpetuating factors, a single-muscle myofascial pain syndrome is often permanently relieved by a single treatment. In the presence of perpetuating factors, initially successful inactivation of myofascial trigger points consistently provides only temporary relief. When these factors are sufficiently severe, specific myofascial treatment may aggravate the patient’s condition. COMPARISON
OF SYNDROMES
I compares the features of fibrositis/fibromyalgia with those of myofascial pain syndromes. Myofascial pain syndromes are more common. Essentially 50 percent of both male and female Air Force recruits were found to have identifiable trigger points, most of which were latent [8]. Few persons reach the age of 50 years without having experienced at least one episode of myofascial pain referred from trigger points, The predominance of women with fibrositis/fibromyalgia (Table I) may relate to chronicity. Acute myofascial pain syndromes occur about equally in both sexes. Recently, Haber and Roos [9] reported a remarkably high incidence of spousal abuse and/or sexual abuse in the development
Table
Volume
81 (suppl
3A)
SYMPOSIUM
and maintenance of chronic pain in women. In their study, more than half of the 151 women they saw in their pain clinic gave this history. Women with fibrositis/fibromyalgia may also have experienced a comparably high incidence of abuse. Initially, myofascial trigger points most commonly occur as a single-muscle syndrome unless trigger points in several muscles were activated together in a single traumatic episode [lo]. Otherwise, multiple-muscle involvement with trigger points usually develops over weeks or months due to perpetuating factors or repeated episodes of muscular stress. Fibrositis/fibromyalgia by definition occurs with multiple tender points. A critical distinction is the specific distribution of pain referred from myofascial trigger points [l 11. Each muscle has its own characteristic location to which it refers pain. The distribution of pain is of paramount importance in the diagnosis of myofascial trigger points and apparently has been disregarded when diagnosing fibrositis/fibromyalgia. Nonrestorative sleep is considered characteristic of fibrositis/fibromyalgia. Sleep disturbance is also common in myofascial pain syndromes, but frequently clears when the trigger points are inactivated. When patients learn which muscle or muscles harbor active trigger points and how to deal with those trigger points, they often find that their difficulty in sleeping was due largely to pain produced by trigger points. The referred pain occurred either when the patients allowed an involved muscle to remain in a shortened position for a prolonged period at night, when the sleeping position produced pressure on a trigger point, or when the muscle was stretched beyond its pain-free range of motion. Patients with myofascial trigger points also frequently report that cold and inclement weather aggravate their symptoms, When these symptoms are due to low serum folic acid levels or inadequate thyroid function, correction of these perpetuating factors relieves their weather sensitivity and improves the responsiveness of their myofascial trigger points to specific local therapy [S]. Skin-roll tenderness is also seen over myofascial trigger points, especially in muscles of the upper thoracic and lumbar spine. Myofascial pain patients with this finding may also have fibrositis/fibromyalgia, if it is a separate entity. Mild, ratchety, “break-away” muscle weakness is characteristic of muscles that permit testing of strength. Some degree of restricted range of motion is characteristic of all muscles with active myofascial trigger points. The range of some muscles is much more restricted by trigger points than the range of others. Trigger points in long slack muscles, such as the latissimus dorsi and the sternocleidomastoid, cause minimal restriction. No abnormality of muscle function is recognized in patients with fibrositis/ fibromyalgia. The local twitch response elicited by snapping palpation
September 29,1986
TABLE
II
ON FlBROSlTlS/FlSROMYALGlA-SIMONS
Comparison Points
of Tender
Points
and Trigger
Myofascial
Fibrositis/Fibromyalgia TenderPoints
TriggerPoints
Manytissues
Musclebellyonly
Prescribed locations Target of referred tenderness’
Any muscle, wherever found Source of referred pain and tenderness Palpable taut band Local twitch response
‘From
(21.
or needle penetration of the tender spot in a palpable band is frequently observed. Whenever present, it is diagnostic of a trigger point. The more active the trigger point, the more vigorous is the local twitch response. Usually, a latent trigger point also exhibits a local twitch response. This phenomenon has not been identified in patients with fibrositis/fibromyalgia. Treatment recommended for fibrositis/fibromyalgia is supportive and nonspecific. Treatment of patients with a myofascial pain syndrome is best directed specifically to the muscles involved with the application of physical modalities, such as stretch and spray, post-isometric relaxation, and trigger point injection [12]. Correction of perpetuating factors is directed to specific mechanical and systemic problems that increase the irritability of muscles [S]. TENDER
POINTS AND TRIGGER
POINTS
A trigger point is always a tender spot. Tender points may, or may not, be trigger points [13]. The definition of tender points in the Dictionary of the Rheumatic Diseases [7] explicitly includes trigger points as one kind of tender point. Since tender points are rarely examined for triggerpoint criteria, it would be no surprise if some, if not most, of the tender points identified in patients diagnosed with fibrositis/fibromyalgia were either trigger points or areas of tenderness referred from trigger points. If so, they should be responsive to specific treatment. Table II compares the characteristics of tender points and trigger points. As indicated in Table II, myofascial trigger points are found only in muscles. Other kinds of trigger points are found in joint capsules, ligaments, scar tissue, and periosteum, among others. These other trigger points are not included under the definition of myofascial trigger points. Tender points are counted only when found in prescribed locations. Smythe [2] identifies a tender point as the target area of referred tenderness; however, he does not discuss the source. In myofascial pain syndromes, trigger points are identified as the source of referred pain and tenderness. Any skeletal muscle can develop myofascial trigger points. Although trigger points have likely locations in each muscle, it is no less a trigger point if it has an unusual location in the muscle.
The American
Journal
of Medicine
Volume
81
(ruppl 3A)
95
SYMPOSIUM
TABLE
ON FlBROSlTlS/FlBROMYALGIA-SIMONS
III
Possible
Myofascial
Origins
Tender Point
of Designated
Tender
Tenderness of a Trigger Point in:
Reference
Upper trapezius muscle
[z51
Upper
Costochondral
[z51
Connective Intercostal 3rd finger
Lateral
junctions
epicondyles
Supraspinatus
(l-2
cm distal
Gluteus
medius
Medial Medial
fat pad epicondyles
PI
muscle
Medial
borders
paraspinal
muscle
of scapulae
muscle
Temporomandibular
insertion
area
joint
Sacroiliac
joint
*Numbers
in parentheses
September 29,
are figure
1986
numbers
(6.1)’
tissue muscle extensor
Supraspinatus
k51 [z51
Scalenus
k51
Gluteus
(35.1 A)
anterior medius
(20.1A)
[16]
-
151
Sternocleidomastoid
(7.1)
M PI
Longissimus thoracis (48.1 D) lliocostalis thoracis (48.1 B) lliocostalis lumborum (48.1C) Lower trapezius (TPs) (6.2) Middle trapezius (TP,) (6.3) Rhomboidei (27.1) lliocostalis thoracis (48.1 D)
[51
Semispinalis Suboccipital
M
Anterior
[51
Masseter (8.1 D) Lateral pterygoid (11 .l)
151
Multifidi
cervicis muscles
deltoid
(16.1 C) (17.1)
(28.1 A)
(48.28)
in [S].
The American Journal of Medicine
Pain and Tenderness Referred from a Trigger Polnt in: Levator scapulae (19.1)’ Lower trapezius (6.2) Supraspinatus (21 .lA) Sternalis (44.1)
(21 .lA)
PI
and lumbar
tendon
trapezius
k51
Dorsal
98
space
muscle
Sternocleidomastoid
Bicipital
~51
muscle
Low cervical, anterior interspinous Low lumbar interspinous ligament
Suboccipital
to)
Points
Volume 81 (suppl3A)
Extensor carpi radialis longus (34.1C) Supinator (36.1) Levator scapulae (19.1) Scalenes (20.1 A) Subscapularis (26.1) MultifidiIrotatores (48.28) Rectus abdominis (49.2A) lliocostalis lumborum (48.1C) Gluteus medius (16) Vastus medialis Triceps brachii (TPB) (32.1 C) Pectoralis major (42.1 B) Pectoralis minor (43.1) Digastric (12.1) Medial pterygoid (10.1) Longissimus thoracis (48.1 D) lliocostalis thoracis (48.1 B) Rectus abdominis (49.2A) Scaleni (20.1 A) Levator scapulae (19.1) Rhomboidei (27.1) lliocostalis thoracis (48.1 D) Serratus posterior sup. (45.1A) Lower trapezius (TP.+) (6.3) Serratus anterior (46.1) Multifidi (16.18) Lower trapezius (TP3) (6.2) lnfraspinatus (22.lA) Anterior deltoid (28.1A) lnfraspinatus (22.lA) Scaleni (20.1 A) Supraspinatus (21 .lA) Pectoralis major (42.1 A) Coracobrachialis (29.1) Biceps brachii (30.1) Lateral pterygoid (11 .l) Medial pterygoid (lO.lA, lO.lC) Masseter (8.1 D) Sternocleidomastoid (7.1 A) Quadratus lumborum (16) Longissimus thoracis (Ll) (48.1D) Gluteus maximus (16) Gluteus medius (16) Piriformis (16) Soleus (16)
SYMPOSIUM
Figure 1. Possible myofascial origins of the trapezius tender point. The tenderness of a fibrositic tender point may be spot tenderness of a trigger point at the arrows in A. However, it also may be tenderness referred from trigger points in other muscles, 6, C, and D. A, trigger point locations in the upper trapezius muscle and their pattern of referred pain and tenderness. 8, pattern of pain and tenderness referred from a lower trapezius trigger point to the region of the trapezius tender point. C, the major pattern of the pain and tenderness referred from trigger points in the levator scapulae muscle includes this tender point area. 0 occasionally, the pattern of referred pain and tenderness from the supraspinatus muscle extends to the trapezius tender point. Reproduced from [15].
C
LEVATOR
SCAPULAE
A reliable characteristic of myofascial trigger points is the palpable taut band of muscle fibers within which the tender trigger point is found. This band is readily palpated in superficial muscles and should clearly distinguish a trigger point from a tender point, which has no such taut band of muscle fibers associated with it. A valuable diagnostic feature, when present, is the local twitch response elicited by snapping palpation of the trigger point [6], as validated by Fricton et al [14]. This transient contraction of the muscle fibers of the palpable band is uniquely characteristic of myofascial trigger points, and is absent in fibrositic tender points that are not trigger points. The local twitch response is easily demonstrated in superficial muscles. Until a careful study is done in which a group of fibrositic patients are also thoroughly examined and treated for trigger points, one can only conjecture as to how fully their symptoms would be explained as being due to myofascial trigger points. ORIGIN OF TENDER
Figure 1 illustrates how, for the trapezius fibrositic tender point, the information in Table III may be applied to locate likely myofascial origins of a designated tender point. Figure 1A illustrates the upper trapezius trigger points (solid arrows) that are located at the fibrositic tender point designated for the trapetius muscle. In addition, Figure 1A shows the referred pain pattern that patients are likely to describe when they have active trigger points in this location. The illustration also includes the stretch position and spray pattern for inactivating this trigger point. Figures 16, C, and D illustrate trigger points in the lower trapezius, levator scapulae, and supraspinatus muscles. The trigger points in these muscles refer pain to the region of the’trapezius fibrositic tender point. One of these trigger points may be the origin of referred tenderness that is observed as the trapezius tender point. When using Table Ill, it is essential to start with a precise drawing of the complete and exact localization of pain experienced by the patient. This drawing greatly helps to identify trigger-point sources of pain. In each case, the pattern of pain referred from a trigger point located at the tender spot is d/stinctively different from the patterns of pain and tenderness referred to this location from trigger points in other muscles. Final confirmation as to whether the suspected muscle harbors trigger points that contribute to the tenderness is obtained by examining all suspected muscles. The muscles are tested for restricted range of motion and weakness. Then they are palpated for tender spots that are located in a palpable band; for a local twitch response; and for reproduction of the pain reported by the patient.
POINT TENDERNESS
The tenderness of a tender point may be produced by fibrositis/fibromyalgia or may have one of two myofascial origins. In one case, the tender spot may be a myofascial trigger point. If this trigger point is active, the patient complains of pain and exhibits tenderness, both of which are referred elsewhere in a characteristic pattern from that muscle. In the other case, the tenderness of the fibrositic tender point may be referred from a myofascial trigger point located elsewhere. Table III is presented for those who are interested in exploring possible myofascial origins of some common tender points.
September
29,1988
ON FIBROSITIS/FIBROMYALGIA-SIMONS
The
American
Journal
of Medlcirw
Volume
81
(suppl3A)
87
SYMPOSIUM
ON FlBROSlTlSiFlBROMYALGIA-SIMONS
Until a group of patients with fibrositis/fibromyalgia is critically examined for possible myofascial sources of the tenderness in their tender points, the question remains as to how often the symptoms are of myofascial origin and how often they are due to another cause. For research purposes, measurement of the degree of tenderness of tender points and trigger points is of paramount importance. Figure 2 illustrates a convenient, reliable pressure-threshold meter that is commercially available. The reliability of this instrument has been carefully validated as an effective way to quantify the extensiveness and relative degree of tenderness of trigger or tender points [17]. It can be used to compare the sensitivity of trigger or tender points with the sensitivity of a reference area. It is especially useful for demonstrating to patients and for documenting to others immediate and sustained improvement following treatment. If fibrositis/fibromyalgia and myofascial pain syndromes are separate entities, which they almost certainly are, a considerable number of patients would be expected to have both conditions at once; therefore, they should benefit from specific treatment of each condition. It would be a mistake to focus only on the patients with severe involvement to the exclusion of the much greater number of patients with treatable myofascial pain due to trigger points in a few muscles and no fibrositis/fibromyalgia. Figure 2. Pressure-threshold meter (model PTH-AF2, Pain Diagnostics and Thermography, Great Neck, New York) measuring the threshold of pain in response to the application of pressure to a tender point or trigger point. This device permits the mapping of pressure sensitivity in the region of tenderness.
ACKNOWLEDGMENT
I gratefully acknowledge the thoughtful review and editing of the manuscript by Janet G. Travell, M.D., and Lois Statham, R.P.T., MS.
REFERENCES 1. 2.
3. 4. 5. 6. 7.
8.
9.
98
Reynolds MD: The development of the concept of fibrositis. J Hist Med Allied Sci 1983; 38: 5-35. Smythe HA: Fibrositis and other diffuse musculoskeletal syndromes. In: Kelley WN, Harris ED, Ruddy S, Sledge CB, eds. Textbook of rheumatology. Philadelphia: W.B. Saunders Company, 1981; 485-493. Wolfe F, Cathey MA: Prevalence of primary and secondary fibrositis. J Rheumatol 1983; 10: 965-968. Bennett RM: Fibrositis: misnomer for a common rheumatic disorder. West J Med 1981; 134: 405-413. Yunus M, Masi AT, Calabro JJ, Shah IK: Primary fibromyalgia. Am Fam Physician 1982; 25: 115-121. Travel1 JG, Simons DG: Myofascial pain and dysfunction: the trigger point manual. Baltimore: Williams & Wilkins, 1983. ARA Glossary Committee: Dictionary of the rheumatic diseases. Volume I: Signs and symptoms. New York: Contact Associates International Ltd, 1983; 44-62. Sola AE, Rodenberger ML, Gettys BB: Incidence of hypersensitive areas in posterior shoulder muscles. Am J Phys Med 1955; 34: 585-590. Haber JD, Roos C: Effects of spouse abuse and/or sexual abuse in the development and maintenance of chronic pain in
September
29, 1988
The Americen
Journal
of Medicine
10. 11. 12. 13. 14.
15.
16. 17.
Volume
women. In: Fields HL, et al, eds. Advances in pain research and therapy, volume 9. New York: Raven Press, 1985. Baker BA: The muscle trigger: evidence of overload injury. J Neurol Orthop Med Surg 1986; 7: 36-44. Travel1 J, Rinzler, SH: The myofascial genesis of pain. Postgrad Med 1952; 11: 425-434. Lewit K, Simons DG: Myofascial pain: relief by post-isometric relaxation. Arch Phys Med Rehabil 1984; 65: 452-456. Wolfe F: Tender points, trigger points, and the fibrositis syndrome. Clin Rheumatol Prac 1984; 2: 36-38. Fricton JR, Auvinen MD, Dykstra D, Schiffman E: Myofascial pain syndrome: electromyographic changes associated with local twitch response. Arch Phys Med Rehabil1985; 66: 314317. Simons DG: Myofascial pain syndromes. In: Basmajian JV, Kirby RL, eds. Medical rehabilitation. Baltimore: Williams & Williams, 1984; 209-215, 313-320. Simons DG, Travel1 JG: Myofascial origins of low back pain. Postgrad Med 1983; 73: 66-77, 81-92, 99-108. Reeves JL, Jaeger B, Graff-Radford SB: Reliability of the pressure algometer as a measure of myofascial trigger point sensitivity. Pain 1986; 24: 313-321.
81 (suppl
3A)
The diagnostic criteria for fibrositis and primary fibromyaigia are similar to those for myofasciai pain syndromes due to trigger points. Tender points in muscles are likely to be myofasciai trigger points; nonmuscular tender points clearly are not myofasciai trigger points, but may be areas of tenderness referred from such trigger points. Myofasciai trigger points refer pain to a distance and restrict range of motion of the muscle. They are associated with a palpable taut band that exhibits a local twitch response of the muscle, and they are responsive to treatment. Persistence of myofasciai trigger points is due to perpetuating factors that can usually be corrected. Although their number is unknown, it is likely that some patients who are diagnosed as having fibrositis/fibromyaigia have multiple myofasciai trigger points aggravated by a powerful perpetuating factor and also have a systemic disease process independent of the myofasciai trigger points. Since myofasciai pain syndromes are treatable, these patients would benefit greatly by identification and relief of the myofasciai component of their pain.
DAVID G. SIMONS, M.D. Huntington
Beach,
California
In the past, many authors have used the same term, fibrositis, to describe quite different patient populations [l]. Recently, Smythe [2], Wolfe and Cathey [3], Bennett [4], and others have adopted a definition of fibrositis that describes essentially the same patient population. Yunus et al [5] have introduced a new term, primary fibromyalgia, using less restrictive criteria to describe a similar, but larger, patient population. Travel1 and Simons [6] have used some overlapping, but additional, specific criteria to identify a much larger patient population with myofascial pain syndromes. The question arises as to whether a patient diagnosed as having fibrositis or primary fibromyalgia has only extensive multiple myofascial trigger points aggravated by severe perpetuating factors; or a separate systemic disorder that is responsible for the symptoms; or some combination of fibrositis or fibromyalgia and myofascial trigger points. To address that issue, this article reviews and compares the diagnostic criteria established for each of the three syndromes. It then considers in detail the distinction between tender points and trigger points. Finally, it illustrates how the myofascial origin of a tender point may be determined. From the Myofascial Pain Clinic, Rehabilitation Medicine Service, Veterans Administration Medical Center, Long Beach, California, and the Department of Physical Medicine and Rehabilitation, University of California, Irvine; Irvine, California. Aequests for reprints should be addressed to Dr. David G. Simons, 324 12th Street, Huntington Beach, California 92848.
September
DEFINITION OF SYNDROMES Smythe [2] in 1981 listed the diagnostic criteria for fibrositis as follows: (1) widespread aching of more than three months’ duration; (2) local tenderness at 12 of 14 specific sites; (3) skin-roll tenderness over the upper scapular region; and (4) disturbed sleep with morning fatigue and stiffness. These criteria were modified by others [3,4] as to the number of tender points and the associated clinical symptoms.
29,1988
The
American
Journal
of Yedlcine
Volume
81 (suppl3A)
93
SYMPOSIUM
TABLE
I
ON FIBROSITIS/FIBROMYALGIA-SIMONS
Diagnostic Features of Fibrositis [2,3] and Primary of Myofascial Pain Syndromes [61 Feature
Prevalence
Pain
sensitive
Skin-roll tenderness Muscle weakness Restricted range of motion Local twitch response of muscle Treatment
FibrositislFibmmyalgia
By definition, Often
or 80%
By definition, ? ? ? Nonspecific
or usually
September 29, 1986
The American
Journal
of Medlclne
[5] Compared
with Those
Myofascial Pain Syndrome Common-50%
male and female
Equal numbers of males Myofascial trigger points
recruits
and females (any number)
Muscle-specific pain patterns; if untreated becomes chronic Common Common especially with low serum folic acid levels and thyroid function inadequacy Occasionally Whenever testable Always some; depends on muscle Frequently observed: diagnostic when present Specific myofascial therapy
or more
Yunus et al [5] in 1982 described the most common symptoms in patients with primary fibromyalgia as generalized aches and pains, tiredness or fatigue, stiffness, anxiety and/or depression, and disturbed sleeping patterns. These symptoms were aggravated by cold or humid weather, fatigue (physical or mental), and physical inactivity. Characteristic physical findings included normal joints and normal muscle strength, multiple tender points (three or more), muscle spasm, tender “fibrositic nodules,” and erythema over the palpated tender points. In the Dictionary of Rheumatic Diseases [7], myofascial pain is defined as follows: “Musculoskeletal pain or aching, diffuse or local, felt anywhere in the body. It is typically deep in character with boundaries that have no apparent anatomical basis, and is often aggravated by movement.” I would further limit this definition to include only pain referred from myofascial trigger points. Travel1 and Simons [6] listed diagnostic criteria for identifying active myofascial trigger points. Patients with a myofascial pain syndrome characteristically present with a history of acute or chronic muscle strain. Their pain is localized in a pattern OFcombination of patterns characteristic of those referred by myofascial trigger points. Each muscle has its own characteristic referred pain pattern. Pain is likely to be aggravated, by prolonged immobilization and by stressful activity of involved muscles. Examination consistently reveals at least some restriction, at times severe, of the stretch range of motion in affected muscles. Careful testing reveals a degree of ratchety, “break-away” muscle weakness. A reproducible spot of exquisite tenderness (trigger point) is located within a taut, palpable band of muscle fibers. Pressure on this spot reproduces a “jump sign” response of the patient. Snapping palpation of the trigger point often produces a local twitch response of the band of muscle fibers. This response is pathognomonic of a trigger point. Likewise, reproduction of the distribution
64
Syndromes
Uncommon-4% with primary and 11% with concomitant fibrositis Predominantly female Multiple (more than seven or more than 12) tender points Widespread and chronic (more than three months)
Sex Tenderness
Sleep disorder Cold and weather
Fibromyalgia
and quality of the patients pain by pressure on, or by needling of, a tender point identifies it as a trigger point. Not all tender spots on the body are trigger points. All trigger points are tender to palpation. The distinction between active and latent trigger points is critical. Only active trigger points are responsible for a clinical report of pain by the patient [6]. On examination, latent trigger points may have all of the other characteristics of active trigger points except that latent trigger points produce no pain at rest or with muscular activity. They are tender and rarely refer pain when palpated. An understanding of the role of perpetuating factors is essential to effective management of chronic myofascial pain syndromes. In the absence of perpetuating factors, a single-muscle myofascial pain syndrome is often permanently relieved by a single treatment. In the presence of perpetuating factors, initially successful inactivation of myofascial trigger points consistently provides only temporary relief. When these factors are sufficiently severe, specific myofascial treatment may aggravate the patient’s condition. COMPARISON
OF SYNDROMES
I compares the features of fibrositis/fibromyalgia with those of myofascial pain syndromes. Myofascial pain syndromes are more common. Essentially 50 percent of both male and female Air Force recruits were found to have identifiable trigger points, most of which were latent [8]. Few persons reach the age of 50 years without having experienced at least one episode of myofascial pain referred from trigger points, The predominance of women with fibrositis/fibromyalgia (Table I) may relate to chronicity. Acute myofascial pain syndromes occur about equally in both sexes. Recently, Haber and Roos [9] reported a remarkably high incidence of spousal abuse and/or sexual abuse in the development
Table
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and maintenance of chronic pain in women. In their study, more than half of the 151 women they saw in their pain clinic gave this history. Women with fibrositis/fibromyalgia may also have experienced a comparably high incidence of abuse. Initially, myofascial trigger points most commonly occur as a single-muscle syndrome unless trigger points in several muscles were activated together in a single traumatic episode [lo]. Otherwise, multiple-muscle involvement with trigger points usually develops over weeks or months due to perpetuating factors or repeated episodes of muscular stress. Fibrositis/fibromyalgia by definition occurs with multiple tender points. A critical distinction is the specific distribution of pain referred from myofascial trigger points [l 11. Each muscle has its own characteristic location to which it refers pain. The distribution of pain is of paramount importance in the diagnosis of myofascial trigger points and apparently has been disregarded when diagnosing fibrositis/fibromyalgia. Nonrestorative sleep is considered characteristic of fibrositis/fibromyalgia. Sleep disturbance is also common in myofascial pain syndromes, but frequently clears when the trigger points are inactivated. When patients learn which muscle or muscles harbor active trigger points and how to deal with those trigger points, they often find that their difficulty in sleeping was due largely to pain produced by trigger points. The referred pain occurred either when the patients allowed an involved muscle to remain in a shortened position for a prolonged period at night, when the sleeping position produced pressure on a trigger point, or when the muscle was stretched beyond its pain-free range of motion. Patients with myofascial trigger points also frequently report that cold and inclement weather aggravate their symptoms, When these symptoms are due to low serum folic acid levels or inadequate thyroid function, correction of these perpetuating factors relieves their weather sensitivity and improves the responsiveness of their myofascial trigger points to specific local therapy [S]. Skin-roll tenderness is also seen over myofascial trigger points, especially in muscles of the upper thoracic and lumbar spine. Myofascial pain patients with this finding may also have fibrositis/fibromyalgia, if it is a separate entity. Mild, ratchety, “break-away” muscle weakness is characteristic of muscles that permit testing of strength. Some degree of restricted range of motion is characteristic of all muscles with active myofascial trigger points. The range of some muscles is much more restricted by trigger points than the range of others. Trigger points in long slack muscles, such as the latissimus dorsi and the sternocleidomastoid, cause minimal restriction. No abnormality of muscle function is recognized in patients with fibrositis/ fibromyalgia. The local twitch response elicited by snapping palpation
September 29,1986
TABLE
II
ON FlBROSlTlS/FlSROMYALGlA-SIMONS
Comparison Points
of Tender
Points
and Trigger
Myofascial
Fibrositis/Fibromyalgia TenderPoints
TriggerPoints
Manytissues
Musclebellyonly
Prescribed locations Target of referred tenderness’
Any muscle, wherever found Source of referred pain and tenderness Palpable taut band Local twitch response
‘From
(21.
or needle penetration of the tender spot in a palpable band is frequently observed. Whenever present, it is diagnostic of a trigger point. The more active the trigger point, the more vigorous is the local twitch response. Usually, a latent trigger point also exhibits a local twitch response. This phenomenon has not been identified in patients with fibrositis/fibromyalgia. Treatment recommended for fibrositis/fibromyalgia is supportive and nonspecific. Treatment of patients with a myofascial pain syndrome is best directed specifically to the muscles involved with the application of physical modalities, such as stretch and spray, post-isometric relaxation, and trigger point injection [12]. Correction of perpetuating factors is directed to specific mechanical and systemic problems that increase the irritability of muscles [S]. TENDER
POINTS AND TRIGGER
POINTS
A trigger point is always a tender spot. Tender points may, or may not, be trigger points [13]. The definition of tender points in the Dictionary of the Rheumatic Diseases [7] explicitly includes trigger points as one kind of tender point. Since tender points are rarely examined for triggerpoint criteria, it would be no surprise if some, if not most, of the tender points identified in patients diagnosed with fibrositis/fibromyalgia were either trigger points or areas of tenderness referred from trigger points. If so, they should be responsive to specific treatment. Table II compares the characteristics of tender points and trigger points. As indicated in Table II, myofascial trigger points are found only in muscles. Other kinds of trigger points are found in joint capsules, ligaments, scar tissue, and periosteum, among others. These other trigger points are not included under the definition of myofascial trigger points. Tender points are counted only when found in prescribed locations. Smythe [2] identifies a tender point as the target area of referred tenderness; however, he does not discuss the source. In myofascial pain syndromes, trigger points are identified as the source of referred pain and tenderness. Any skeletal muscle can develop myofascial trigger points. Although trigger points have likely locations in each muscle, it is no less a trigger point if it has an unusual location in the muscle.
The American
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SYMPOSIUM
TABLE
ON FlBROSlTlS/FlBROMYALGIA-SIMONS
III
Possible
Myofascial
Origins
Tender Point
of Designated
Tender
Tenderness of a Trigger Point in:
Reference
Upper trapezius muscle
[z51
Upper
Costochondral
[z51
Connective Intercostal 3rd finger
Lateral
junctions
epicondyles
Supraspinatus
(l-2
cm distal
Gluteus
medius
Medial Medial
fat pad epicondyles
PI
muscle
Medial
borders
paraspinal
muscle
of scapulae
muscle
Temporomandibular
insertion
area
joint
Sacroiliac
joint
*Numbers
in parentheses
September 29,
are figure
1986
numbers
(6.1)’
tissue muscle extensor
Supraspinatus
k51 [z51
Scalenus
k51
Gluteus
(35.1 A)
anterior medius
(20.1A)
[16]
-
151
Sternocleidomastoid
(7.1)
M PI
Longissimus thoracis (48.1 D) lliocostalis thoracis (48.1 B) lliocostalis lumborum (48.1C) Lower trapezius (TPs) (6.2) Middle trapezius (TP,) (6.3) Rhomboidei (27.1) lliocostalis thoracis (48.1 D)
[51
Semispinalis Suboccipital
M
Anterior
[51
Masseter (8.1 D) Lateral pterygoid (11 .l)
151
Multifidi
cervicis muscles
deltoid
(16.1 C) (17.1)
(28.1 A)
(48.28)
in [S].
The American Journal of Medicine
Pain and Tenderness Referred from a Trigger Polnt in: Levator scapulae (19.1)’ Lower trapezius (6.2) Supraspinatus (21 .lA) Sternalis (44.1)
(21 .lA)
PI
and lumbar
tendon
trapezius
k51
Dorsal
98
space
muscle
Sternocleidomastoid
Bicipital
~51
muscle
Low cervical, anterior interspinous Low lumbar interspinous ligament
Suboccipital
to)
Points
Volume 81 (suppl3A)
Extensor carpi radialis longus (34.1C) Supinator (36.1) Levator scapulae (19.1) Scalenes (20.1 A) Subscapularis (26.1) MultifidiIrotatores (48.28) Rectus abdominis (49.2A) lliocostalis lumborum (48.1C) Gluteus medius (16) Vastus medialis Triceps brachii (TPB) (32.1 C) Pectoralis major (42.1 B) Pectoralis minor (43.1) Digastric (12.1) Medial pterygoid (10.1) Longissimus thoracis (48.1 D) lliocostalis thoracis (48.1 B) Rectus abdominis (49.2A) Scaleni (20.1 A) Levator scapulae (19.1) Rhomboidei (27.1) lliocostalis thoracis (48.1 D) Serratus posterior sup. (45.1A) Lower trapezius (TP.+) (6.3) Serratus anterior (46.1) Multifidi (16.18) Lower trapezius (TP3) (6.2) lnfraspinatus (22.lA) Anterior deltoid (28.1A) lnfraspinatus (22.lA) Scaleni (20.1 A) Supraspinatus (21 .lA) Pectoralis major (42.1 A) Coracobrachialis (29.1) Biceps brachii (30.1) Lateral pterygoid (11 .l) Medial pterygoid (lO.lA, lO.lC) Masseter (8.1 D) Sternocleidomastoid (7.1 A) Quadratus lumborum (16) Longissimus thoracis (Ll) (48.1D) Gluteus maximus (16) Gluteus medius (16) Piriformis (16) Soleus (16)
SYMPOSIUM
Figure 1. Possible myofascial origins of the trapezius tender point. The tenderness of a fibrositic tender point may be spot tenderness of a trigger point at the arrows in A. However, it also may be tenderness referred from trigger points in other muscles, 6, C, and D. A, trigger point locations in the upper trapezius muscle and their pattern of referred pain and tenderness. 8, pattern of pain and tenderness referred from a lower trapezius trigger point to the region of the trapezius tender point. C, the major pattern of the pain and tenderness referred from trigger points in the levator scapulae muscle includes this tender point area. 0 occasionally, the pattern of referred pain and tenderness from the supraspinatus muscle extends to the trapezius tender point. Reproduced from [15].
C
LEVATOR
SCAPULAE
A reliable characteristic of myofascial trigger points is the palpable taut band of muscle fibers within which the tender trigger point is found. This band is readily palpated in superficial muscles and should clearly distinguish a trigger point from a tender point, which has no such taut band of muscle fibers associated with it. A valuable diagnostic feature, when present, is the local twitch response elicited by snapping palpation of the trigger point [6], as validated by Fricton et al [14]. This transient contraction of the muscle fibers of the palpable band is uniquely characteristic of myofascial trigger points, and is absent in fibrositic tender points that are not trigger points. The local twitch response is easily demonstrated in superficial muscles. Until a careful study is done in which a group of fibrositic patients are also thoroughly examined and treated for trigger points, one can only conjecture as to how fully their symptoms would be explained as being due to myofascial trigger points. ORIGIN OF TENDER
Figure 1 illustrates how, for the trapezius fibrositic tender point, the information in Table III may be applied to locate likely myofascial origins of a designated tender point. Figure 1A illustrates the upper trapezius trigger points (solid arrows) that are located at the fibrositic tender point designated for the trapetius muscle. In addition, Figure 1A shows the referred pain pattern that patients are likely to describe when they have active trigger points in this location. The illustration also includes the stretch position and spray pattern for inactivating this trigger point. Figures 16, C, and D illustrate trigger points in the lower trapezius, levator scapulae, and supraspinatus muscles. The trigger points in these muscles refer pain to the region of the’trapezius fibrositic tender point. One of these trigger points may be the origin of referred tenderness that is observed as the trapezius tender point. When using Table Ill, it is essential to start with a precise drawing of the complete and exact localization of pain experienced by the patient. This drawing greatly helps to identify trigger-point sources of pain. In each case, the pattern of pain referred from a trigger point located at the tender spot is d/stinctively different from the patterns of pain and tenderness referred to this location from trigger points in other muscles. Final confirmation as to whether the suspected muscle harbors trigger points that contribute to the tenderness is obtained by examining all suspected muscles. The muscles are tested for restricted range of motion and weakness. Then they are palpated for tender spots that are located in a palpable band; for a local twitch response; and for reproduction of the pain reported by the patient.
POINT TENDERNESS
The tenderness of a tender point may be produced by fibrositis/fibromyalgia or may have one of two myofascial origins. In one case, the tender spot may be a myofascial trigger point. If this trigger point is active, the patient complains of pain and exhibits tenderness, both of which are referred elsewhere in a characteristic pattern from that muscle. In the other case, the tenderness of the fibrositic tender point may be referred from a myofascial trigger point located elsewhere. Table III is presented for those who are interested in exploring possible myofascial origins of some common tender points.
September
29,1988
ON FIBROSITIS/FIBROMYALGIA-SIMONS
The
American
Journal
of Medlcirw
Volume
81
(suppl3A)
87
SYMPOSIUM
ON FlBROSlTlSiFlBROMYALGIA-SIMONS
Until a group of patients with fibrositis/fibromyalgia is critically examined for possible myofascial sources of the tenderness in their tender points, the question remains as to how often the symptoms are of myofascial origin and how often they are due to another cause. For research purposes, measurement of the degree of tenderness of tender points and trigger points is of paramount importance. Figure 2 illustrates a convenient, reliable pressure-threshold meter that is commercially available. The reliability of this instrument has been carefully validated as an effective way to quantify the extensiveness and relative degree of tenderness of trigger or tender points [17]. It can be used to compare the sensitivity of trigger or tender points with the sensitivity of a reference area. It is especially useful for demonstrating to patients and for documenting to others immediate and sustained improvement following treatment. If fibrositis/fibromyalgia and myofascial pain syndromes are separate entities, which they almost certainly are, a considerable number of patients would be expected to have both conditions at once; therefore, they should benefit from specific treatment of each condition. It would be a mistake to focus only on the patients with severe involvement to the exclusion of the much greater number of patients with treatable myofascial pain due to trigger points in a few muscles and no fibrositis/fibromyalgia. Figure 2. Pressure-threshold meter (model PTH-AF2, Pain Diagnostics and Thermography, Great Neck, New York) measuring the threshold of pain in response to the application of pressure to a tender point or trigger point. This device permits the mapping of pressure sensitivity in the region of tenderness.
ACKNOWLEDGMENT
I gratefully acknowledge the thoughtful review and editing of the manuscript by Janet G. Travell, M.D., and Lois Statham, R.P.T., MS.
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3. 4. 5. 6. 7.
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Reynolds MD: The development of the concept of fibrositis. J Hist Med Allied Sci 1983; 38: 5-35. Smythe HA: Fibrositis and other diffuse musculoskeletal syndromes. In: Kelley WN, Harris ED, Ruddy S, Sledge CB, eds. Textbook of rheumatology. Philadelphia: W.B. Saunders Company, 1981; 485-493. Wolfe F, Cathey MA: Prevalence of primary and secondary fibrositis. J Rheumatol 1983; 10: 965-968. Bennett RM: Fibrositis: misnomer for a common rheumatic disorder. West J Med 1981; 134: 405-413. Yunus M, Masi AT, Calabro JJ, Shah IK: Primary fibromyalgia. Am Fam Physician 1982; 25: 115-121. Travel1 JG, Simons DG: Myofascial pain and dysfunction: the trigger point manual. Baltimore: Williams & Wilkins, 1983. ARA Glossary Committee: Dictionary of the rheumatic diseases. Volume I: Signs and symptoms. New York: Contact Associates International Ltd, 1983; 44-62. Sola AE, Rodenberger ML, Gettys BB: Incidence of hypersensitive areas in posterior shoulder muscles. Am J Phys Med 1955; 34: 585-590. Haber JD, Roos C: Effects of spouse abuse and/or sexual abuse in the development and maintenance of chronic pain in
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