Trapezius Myalgia

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Search Strategy

We searched on different databases such as PubMed and PEDro using the following words in our search terms: myalgia, trapezius myalgia, neck-shoulder disorders, definition, epidemiology, clinical presentation, outcome, physical therapy, surgery, medical intervention, treatment, diagnosis... We only used articles of which the full text was available.

Definition/Description

Myalgia in generally is known as a muscle ache or muscle pain. In case of trapezius myalgia (TM) the pain is localized in the superior fibres, or otherwise the superior part, of the trapezius muscle¹ [LoE: 2B]. Mostly the neck and shoulder area is painful and uncomfortable² [LoE: 2B]. TM is not a medical disorder or disease but rather a symptom of an existing underlying condition. The pain in the muscle can last a few days or longer. It can be continuous and can range from mild to excruciating³ [LoE: 5].

Clinically Relevant Anatomy

The trapezius muscle is a large trapezoid shaped muscle that makes up the majority of the superficial posterior cervical and thoracic musculature and consists of three parts^{4 5}:

‐ Trapezius pars descendens (superior part)
‐ Trapezius pars transversa (middle part)
‐ Trapezius pars ascendens (inferior part)

The visualisation of the course, functions and innervation of all three parts is shown in the following video:
https://www.youtube.com/watch?v=P5sOhwBZon8 
In TM it is the superior part that is painful¹.This part originates from the linea nuchalis superior, the protuberantia externa and through the nuchal ligament from all cervical spinous processes. The insertion is on the lateral third of the clavicula and the acromion⁴.

All parts work together to stabilize the scapula⁵ . The superior fibers are responsible for upward rotation and elevation of the scapula, homolateral lateroflexion and heterolateral rotation of the head. When activated bilaterally, the superior part ensures neck extension⁴. 

Etiology/Epidemiology 

Etiology
There has been a lot of research on the aetiology of work related neck and shoulder disorders and hence of TM. Researchers agree that the disorders arise from both biomechanical and psychosocial factors. Within the biomechanical dimension the m. Trapezius plays an important role. TM may be associated with a lot of peripheral and/or central changes which can interact resulting in muscle pain and fatigue⁶.

The review of Larsson et al.⁶ confirmed that highly repetitive work (industrial jobs like fish processing workers, employees of a car assemblage plant⁴⁷ or from the metal industry ⁴⁸ forceful exertions, high level of static contractions, prolonged static loads, extreme postures or a combination of these factors are possible causes of neck and shoulder disorders (which include TM) in the working population. Several studies reported altered metabolisms and increased intramuscular levels of algesic substances. These local peripheral muscular processes could explain the chronic pain in neck-shoulder disorders. The review of Gerdle et al.⁷  confirms these hypothesises by finding elevated levels of 5-HT, glutamate, lactate and pyruvate in localized chronic myalgias. Other changes that occur at the muscular level are mitochondrial disturbances in the type I fibres^{6 8}  and reduced capillary density and circulation^{6 8}. These changes can possibly cause interferences in the oxidative metabolism of the muscles.

In chronic TM Larsson et al.⁹  found an impaired regulation of local blood flow in the upper trapezius muscle that is not due to intramuscular pressure, to be an important cause of nociceptive pain.

Centrally a reorganization of the neuromotor control strategies takes place. The superficial cervical extensor muscles show a higher muscle activation and deplete faster. So the superficial upper trapezius shows a higher activation then the erector spinae. Szeto et al.¹⁰  demonstrate in their study that the greater recruitment of type II fibres in symptomatic patients could possibly explain the muscle fatigue.

Not only the biomechanical factors play an important role in het onset of TM. Larsson et al.⁶ has described a causal relationship between psychosocial factors and the occurrence of neck and shoulder disorders. There is some evidence that there is a link between disorders and high quantitative and qualitative demands, lack of support of colleagues, low job control and low influence. They also demonstrated a relationship between mental stress at work and disorders. However, the limited amount of literature focusing on causal relationships between psychosocial factors and disorders makes it difficult to estimate the influence of these factors and how they may interact with the biomechanical and individual factors.

Epidemiology
Most epidemiological studies are about neck-shoulder disorders in general. Trapezius myalgia belongs to these kind of disorders and therefore belongs to 20-30% of the estimated prevalence of upper-extremity symptoms in the working population.
Gender seems to play an important role in the development of neck disorders, since the prevalence is much higher among women. Women more often experience neck pain and develop persistent pain than men do. This difference might be explained by the content of their jobs. Women’s work tasks involve more static load on the neck muscles, high repetitiveness, low control and high mental demands, which are all risk factors for develloping neck disorders ( see ‘aetiology’).⁶

The systematic review of Waersted et al.¹¹ states that computer work does not increase the risk of developing musculoskeletal disorders.

Chronic TM concerns 10-20% of the 20% of the adult population with severe chronic pain in the neck and shoulder region.⁷ The chronic form of TM also shows a higher prevalence in women, but also in low income groups⁷. Likewise, in one-third of the office workers with chronic neck pain, TM present¹².

Characteristics/Clinical Presentation

Typical symptoms of “myalgia” are¹³:
- sudden onset of (severe) pain that lingers for a few days to weeks. The pain is associated with stiffness and spasms
- heaviness of the head and occipital headache
- tenderness of the affected area

Other symptoms¹³:
- nausea and vomiting
- onset of fever
- anxiety and depression
- stiffness of the affected muscle
- vertigo
- numbness and tingling sensations

In case of acute myalgia, the patient can be severely incapacitated because of the pain. Chronic myalgia typically causes pain and stiffness after periods of inactivity. The pain usually eases after reasonable exercise.¹³

Valachy¹⁴  describes the clinical presentation of TM to be pain, spasms and tenderness in the upper trapezius. Trigger points in the muscle can cause painful headaches behind the eye, into the temple and in the back of the neck. The review of Larsson et al.⁶ confirms this.

Differential Diagnosis

According to the review of Larsson et al.⁶ TM can only be diagnosed when neck pain, muscle tightness and trigger points are present, but tension neck syndrome or cervical syndrome is not present.

Tension neck syndrome shows the same symptoms, with the pain radiating from the neck to the back of the head and an additional sense of fatigue or stiffness in the neck. In cervical syndrome the pain radiates from the neck to the upper extremity, there is also decreased sensibility in hands and fingers and muscle weakness in the upper limb.

Other pathologies that can cause similar symptoms are:
- Cervicalgia: neck pain and limited mobility in at least four directions⁶
- Thoracic Outlet Syndrome: pain in the neck, trapezius region, supraclavicular region, chest and occipital region and paresthesia in the upper extremity ⁶

Diagnostic Procedures

The review of Larsson et al.⁶ confirms that the basis for diagnostic criteria of neck and shoulder myalgia is not very clear and that the diagnostic terminology and methods for assessment are variable. If the progressing neck and shoulder pain isn’t accompanied by other symptoms or signs (cfr. red flags), specific investigations such as radiography, magnetic resonance imaging, electromyography or nerve conductance testing aren’t required.

When there’s dubiety between several conditions, certain medical tests¹⁵  are helpful to eliminate certain diagnoses. Radiography and MRI eliminate bone or joint disorders, a blood test can detect inflammation and therefore eliminate underlying conditions that may cause muscle disorders. Electromyography can differentiate between a muscle or nerve disorder if one is present. For the diagnosis of inherited metabolic disorders, connective tissue disease, eosinophilia-myalgia, sarcoidosis and trichinosis, muscle biopsy is indicated.

In general, no objective diagnostic methods are available. The diagnosis is mostly based on symptom presentation and history of illness.^{2 15}

Outcome measures

Visual analogue scale¹
This scale measures general pain, worst pain and present pain on a 100 mm line. The endpoints of the line are no pain and worst possible pain.

Pain thresholds
In the study of Waling et al.¹ the pain of the patient is measured in six trigger points (labelled tp 2 right, tp 2 left, tp 4 right, tp 4 left, tp 5 right and tp 5 left). These points were selected by Simons and Travell (1893)¹⁶ . The pain is measured with a pressure algometer, showing the applied pressure in kPa and indicating the rate of pressure increase. The patient has to indicate when the given sensation starts to hurt. This is the pain threshold. If the therapy is successful, the pain threshold should be higher, so it takes longer for the patient to experience a sensation as pain.

Pain drawing¹
The pain distribution and the characteristics of the pain are marked on a drawing of a body. The total body area marked as painful is interpreted as a percentage of the body area.
Ransford et al.¹⁷  developed such a pain drawing. Margolis et al.¹⁸ created a method to calculate the percentage of painful body area.

McGill pain questionnaire¹⁹
The MPQ is a subjective questionnaire used to asses the quality and intensity of pain in patients with a number of diagnoses.

Neck disability index ^{20 21}
The NDI is a questionnaire that inquires the functional status of a patient concern the following 10 items: pain, personal care, lifting, reading, headaches, concentration, work, driving, sleeping and recreation.

Neck Bournemouth Questionnaire ^{22 23}
The NBQ is administered to patients with non specific neck pain. It assesses pain, disability, affective aspects and cognitive aspects of the neck pain. The questionnaire contains seven items: pain intensity, function in activities of daily living, function in social activities, anxiety, depression levels, fear avoidance behavior and locus of control behavior.

Northwick Park Questionnaire
The NPQ is used to measure neck pain and the disabilities associated with it.

Nordic musculoskeletal Questionnaire (NMQ) for neck and shoulder trouble ^{25 26 27}
This questionnaire focuses on the diagnosis of musculoskeletal problems and is specifically used in chronic work-related cases of TM. The questionnaire is composed of two sections. The first one is a general questionnaire of 40 forced-choice items to identify the areas of the body causing musculoskeletal problems. A body map is added to indicate nine symptom sites. The patient is asked if they had any musculoskeletal problems in the last year and the last week that prevented normal activity. In the second section additional questions about the neck and shoulders are asked to get more details about the issue. This section consists of 25 forced-choice questions about accidents affecting the areas and the functional impact at home and at work in the last week.
The study of Kuorinka et al.²⁸ shows the reliability of the questionnaire to be acceptable for a screening tool. Dickinson et al.²⁹  have made some improvements to the questionnaire. Ohlsson et al.³⁰ found that the sensitivity ranges from 66% to 92% and the specificity from 71% to 88%. The NMQ is thus repeatable, sensitive and can be used as a screening and as a surveillance tool.

Examination

A standard clinical examination on the neck and upper extremities can be useful for diagnosing TM. The examination consists of questions about pain, tiredness and stiffness, physical tests including range of motion (ROM) and muscle tightness, pain provocation, sensibility, strength and palpation of trigger points.^{6 31}

Patients suffering from TM usually have neck pain, tightness of the trapezius muscle and palpable trigger points in the trapezius muscle.^{31 32}

A surface electromyography can be done to evaluate muscle function. Parameters that can be studied are amplitude, timing, conduction velocity, fatigability and characteristic frequencies/patterns.³³

In cases where a typical anamnesis with progressing neck and shoulder pain and no other symptoms or signs is mentioned and where a clinical examination can confirm the diagnosis, there is no need for supplementary objective investigations such as a surface electromyography.⁶ But the study of Juul-Kristensen et al. [LoE: 3B] found that for 60% of those with self-reported neck symptoms of a certain duration and intensity, a clinical examination can confirm one or more diagnoses, with trapezius myalgia (38%), tension neck syndrome (17%), and cervicalgia (17%) being the most frequent. But in the other 40% a supplementary objective investigation is needed to make a correct diagnosis.⁴⁹

Medical Management

The most common medical management for TM is medication for pain relief.

According to the review of Jensen et al most of the pharmacological treatments lack effects or haven’t enough evidence. An intra-muscular injection with lidocaine only has short term effect on pain in chronic neck pain. Intravenous methylprednisolone and lidocaine works in short term on pain. There is not enough evidence on the long term effects of surgical interventions. ^34 24

Recent Related Research (from Pubmed)

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References

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2. Falla D. Et al., An electromyographic analysis of the deep cervical flexor muscles in performance of craniocervical flexion., 2003, Physical Therapy, 83(10), 899-906. (1B)

3. Falla D. et al., Feedforward activity of the cercvical flexor muscles during voluntary arm movements is delayed in chronic neck pain., 2004, Experimental Brain Research, 157(1), 43-48. (2B)

4. Hägg G.M. et al., Human muscle fibre abnormalities related to occupational load., European Journal of Applied Physiology, 2000, 83(2-3), 159-165. (1A)

5. Kadi F. et al., Pathological mechanisms implicated in localized female trapeziusmyalgia ., Pain, 1998, 78, 191-196. (2B)

6. Larsson B. et al., Blood supply and oxidative metabolism in muscle biopsies of female cleaners with and without myalgie., Clinical Journal of Pain, 2004, 20(6), 440-446. (2B)

7. Larsson et al., Work related neck-shoulder pain: a review on magnitude, risk factors, biochemical characteristics, clinical picture and preventive interventions, Best practice and research clinical rheumatology, 2007, 21(3), 447-463. (1A)

8. Nederhand M.J. et al., Cervical muscle dysfunction in the chronic whiplash associated disorder grade II (WAD-II)., 2000, Spine, 25(15), 1938-43.9. (2B)

9. Silverman J.L. et al., Quantitative cervical flexor strength in healthy subjects and in subjects with mechanical neck pain., 1991, Archives of Physical and Medical Rehabilitation, 72(9), 679-681. (2B)

10. Szeto G. Et al., A comparison of symptomatic and asymptomatic office workers performing monotonous keyboard work- 1: neck and shoulder muscle recruitment patterns., 2005, Manual Therapy, 10, 270-280.

11. Uhlig Y. et al., Fiber composition and fiber transformations in neck muscles of patients with dysfunction of the cervical spine. Journal of Orthopedic Research, 1995, 13(2), 240-249. (2B)

12. Anna Sjörs, Physiological responses to low-force work and psychosocial stress in women with chronic trapezius myalgia, BioMed Central, 2009 (1A)

13. Ghafouri N., High levels of N-palmitoylethanolamide and N-stearoylethanolamide in microdialysate samples from myalgic trapezius muscle in women, PLOS-one 2011;6(11):e27257 (2B)

14. Vernon H, Schneider M., Chiropractic management of myofascial trigger points and myofascial pain syndrome: a systematic review of the literature., J Manipulative Physiol Ther. 2009 Jan;32(1):14-24. Level of evidence (1A)

15. De las penas, C.F., Campo, M.S., Carnero, J.F., Page, J.C., Manual therapies in myofascial triggerpoint treatment: a systematic review., journal of Body work and Movement Therapies (2005) 9,27–34. Level of evidence (1A)

16. Holtermann A, Søgaard K, Christensen H, Dahl B, Blangsted AK., The influence of biofeedback training on trapezius activity and rest during occupational computer work: a randomized controlled trial., Eur J Appl Physiol. 2008 Dec;104(6):983-9. Level of evidence (1B)

17. Andersen LL, Kjaer M, Søgaard K, Hansen L, Kryger AI, Sjøgaard G., Effect of two contrasting types of physical exercise on chronic neck muscle pain., Arthritis Rheum. 2008 Jan 15;59(1):84-91. Level of evidence (1B)

18. Waling K, Järvholm B, Sundelin G., Effects of training on female trapezius Myalgia: An intervention study with a 3-year follow-up period., Spine (Phila Pa 1976). 2002 Apr 15;27(8):789-96. Level of evidence (1B)