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 basis for diagnostic criteria of neck and shoulder myalgia is not very clear, and the diagnostic terminology and methods for assessment are variable. This indicates that several more or less specific and partly overlapping diagnoses exist. Progressing neck and shoulder pain accompanied with no other symptoms or signs (red flags) does not require specific investigations like radiography, magnetic resonance imaging, electromyography or nerve conductance testing. A standardized clinical examination for the clinical diagnosis of neck and shoulder myalgia contains questions on pain, tiredness and stiffness on the day of examination and physical tests. These test measure range of motion and tightness of muscles, pain threshold and sensitivity, muscle strength and palpation tender points⁸.

Possible risk factors

In the review of Larsson et al. an overview is given of the possible risk factors for work-related upper-extremity disorders. The conclusion stated that strong evidence was found for a causal relationship between;

• Neck disorders and highly repetitive work
• Forceful exertions
• High level of static contractions
• Prolonged static loads and extreme postures
• Combinations of these previously named factors

But there was insufficient evidence for vibration as a risk factor. Also gender seems to play an important role in the development of neck disorders, since the prevalence is much higher among women. This difference can possibly explained with the fact that women’s jobs involve more work tasks with static load on the neck muscles, high repetitiveness, low control and high mental demands which are all risk factors for developing neck-shoulder pain.

After the biomechanical and individual factors there are also psychosocial factors that have a causal relationship with the occurrence of neck and shoulder disorders⁸. There is some evidence for 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 disorders¹.

It seems logical, as we see all of the risk factors, that there is evidence for an increased risk for development of upper-extremity disorders among computer users. It was suggested that this could be due to constrained postures, constant force and highly repetitive movements as well as psychosocial factors such as time constraints and high quantitative demands⁸.

Physical Therapy Management

• Biofeedback
• Specific Strength training: 1-arm row, shoulder abduction, shoulder elevation, reverse flies and upward row.
• General endurance training
• Manual techniques: ischemic compression, transverse friction massage, stretching
•Tens
• Laser therapy

Prevention:
Prolonged stress in the upper trapezius muscle can activate latent trigger points or maintain pain in active trigger points. Biofeedback in the form of EMG of the upper trapezius muscle during work leeds to significant less activity and more rest pauses of the specific muscle. Therefore biofeedback might be useful in the treatment of trapezius myalgia. (Holtermann et al, 2008; level 1B)

Physical exercise:
Exercise seems to have beneficial effects on patients suffering from work related trapezius myalgia. Both general fitness training and specific strength training generate significant effects on diminishing pain. However strength training has proven to be even more effective compared to general fitness training. Prolonged effects 10 weeks after intervention were found (Andersen et al., 2008; level 1B). Other studies noted that long-term effects after 3 years disappeared. (Waling et al., 2002; level 1B)

Manual therapies:
Ischemic compression, stretch of the upper trapezius muscle, transverse friction massage are manual techniques to help patients with trapezius myalgia. These techniques appear to have instant improvement on pain. Long-term effects have not yet been well investigated. (De Las Penas et al., 2005; Level 1A)

Physical applications:
Transcutaneous Electro Nerve Stimulation (TENS) and laser therapy seemed to have positive short-term effects. However, more investigation on the long-term effect of these applications are needed. Also the most efficient type, frequency and duration of laser therapy require additional research. (Vernon & Schneider, 2009; level 1A)

Recent Related Research (from Pubmed)

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References

1. Ariëns A.M. et al., High Quantitative Job Demands and Low Coworker Support As Risk Factors for Neck Pain., 2001, Spine, 26, 1896–1903. (2B)

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)