Trapezius Pain Research Articles

Rapid muscle activation and force capacity in conditions of chronic musculoskeletal pain

Background The association between musculoskeletal pain and decreased maximal muscle strength capacity has been extensively studied, but knowledge about functional rapid force capacity in conditions of chronic musculoskeletal pain is lacking. The objective of this study is to investigate rapid muscle activation and force capacity of chronically painful muscles. Methods Cross-sectional study with 42 women with chronic trapezius myalgia, and 20 healthy matched controls. Maximal capacity was determined as peak torque and peak EMG amplitude of the painful trapezius and painfree deltoid muscles during the stable high-force phase of maximal voluntary shoulder abduction, whereas rapid capacity was determined as the steepest slope of the torque–time and EMG–time curves, defined as rate of torque development and rate of EMG rise. Intensity of pain was registered prior to the test on a visual-analogue-scale. Findings Peak torque was 18% lower at 115° shoulder joint angle in women with myalgia compared with healthy controls ( P < 0.001), with a corresponding 29% lower level of peak EMG specifically of the painful trapezius muscle ( P < 0.001). Rate of torque development was 33–54% lower ( P < 0.001), with a corresponding 21–35% lower level of rate of EMG rise of both the painful trapezius and painfree deltoid ( P < 0.0001). Intensity of pain showed higher association with parameters of rapid capacity ( R = −0.33 to −0.53, P < 0.001–0.05) than with maximal capacity ( R = −0.15 to −0.41, P < 0.01-ns). Interpretation In conditions of chronic musculoskeletal pain, the ability to rapidly activate painful and painfree synergistic muscles is more severely impaired than maximal muscle activation. These findings have clinical relevance for rehabilitation of chronically painful muscles.

Torque–EMG–velocity relationship in female workers with chronic neck muscle pain

The present study investigated the effect of chronic neck muscle pain (defined as trapezius myalgia) on neck/shoulder muscle function during concentric, eccentric and static contraction. Forty-two female office workers with trapezius myalgia (MYA) and 20 healthy matched controls (CON) participated. Isokinetic (−60, 60 and 180° s −1) and static maximal voluntary shoulder abductions were performed in a Biodex dynamometer, and electromyography (EMG) obtained in the trapezius and deltoideus muscles. Muscle thickness in the trapezius was measured with ultrasound. Pain and perceived exertion were registered before and after the dynamometer test. The main findings were that shoulder abduction torque (at −60 and 60° s −1) and trapezius EMG amplitude (at −60, 0 and 60° s −1) were significantly lower in MYA compared with CON ( p<0.001–0.05). Deltoideus EMG and trapezius muscle thickness were not significantly different between the groups. While perceived exertion increased in both groups in response to the test ( p<0.0001), pain increased in MYA only ( p<0.0001). In conclusion, having trapezius myalgia was associated with decreased strength capacity and lowered activity of the painful trapezius muscle. The most consistent differences—in terms of both torque and EMG—were found during slow concentric and eccentric contractions. Activity of the synergistic pain free deltoideus muscle was not significantly lower, indicating specific inhibitory feedback of the painful trapezius muscle only. Parallel increase in pain and perceived exertion among MYA were observed in response to the maximal contractions, emphasizing that heavy physical exertion provokes pain increase only in conditions of myalgia.

Factors affecting the timing of recovery from whiplash neck injuries: study of a cohort of 134 patients pursuing litigation

A cohort of 134 patients presenting in medico-legal practice with whiplash neck injury following a motor vehicle accident was studied prospectively by personal interviewing. Injury- and patient-related factors with possible influence to the timing of recovery were analysed with univariate and multivariate statistical methods. Logistic regression showed significant association between high physical demand patient occupation and recovery within 6 months from injury (P = 0.036, coefficient 1.5, odds ratio 4.47) while initiation of physiotherapy treatment was associated with prolongation of symptoms for more than 6 months following injury (P < 0.001, coefficient -2.6, odds ratio 0.08). An association between development of arm pain (P = 0.01), upper limb numbness or paraesthesia (P = 0.03) and bilateral trapezius pain (P = 0.04) and persistence of whiplash-related symptoms was also observed. These findings must be taken into account in evaluation and treatment of patients with acute whiplash injuries pursuing litigation.

A reply

We would like to thank Dr Crocker and colleagues for their interest in our study. We are happy to respond to the queries that they raised. Firstly, in the Modified Observer's Assessment of Alertness/Sedation (OAAS) scale, level 1 describes a patient who responds to painful trapezius squeeze, and level 2 corresponds to a patient who responds to mild prodding or shaking. We did not want to apply painful stimuli to assess the alertness or sedation status of our patients. Therefore, level 2 was defined by us as a patient who does not respond to mild prodding or shaking, and this level was then regarded as a surrogate for loss of consciousness. We agree with Crocker et al. that we actually used a modified OAAS scale. Second, we are aware that one limitation of our study was the lack of measurements of propofol plasma concentrations; this was pointed out by us in the discussion of our paper. It remains unclear, however, whether plasma concentrations would have improved the validity of our findings. Finally, alcohol and nicotine consumption may indeed be linked in some individuals. Thus, we cannot rule out that in our study cohort, alcohol consumption was a confounding factor. In the absence of valid data on the impact of alcohol consumption on the hypnotic efficacy of propofol, this assumption, however, remains speculative.

Experimental muscle pain results in reorganization of coordination among trapezius muscle subdivisions during repetitive shoulder flexion

The aim of the study was to examine the effect of experimental unilateral upper trapezius muscle pain on the relative activation of trapezius muscle subdivisions bilaterally during repetitive movement of the upper limb. Surface EMG signals were detected from nine healthy subjects from the upper, middle and lower divisions of trapezius during a repetitive bilateral shoulder flexion task. Measurements were performed before and after injection of 0.5 ml hypertonic (pain condition) and isotonic (control) saline into the upper division of the right trapezius muscle in two experimental sessions. On the painful side, upper trapezius showed decreased EMG amplitude (average rectified value, ARV) and lower trapezius increased ARV throughout the entire task following the injection of hypertonic saline (40.0 +/- 22.2 vs. 26.0 +/- 17.4 microV, and 12.5 +/- 7.6 vs. 25.6 +/- 14.8 microV, respectively, at the beginning of the contraction). On the side contralateral to pain, greater estimates of ARV were identified for the upper division of trapezius as the task progressed (37.4 +/- 20.2 vs. 52.7 +/- 28.4 microV, at the end of the contraction). Muscle fiber conduction velocity did not change with pain in all three divisions of the right trapezius muscle. The results suggest that local elicitation of nociceptive afferents in the upper division of the trapezius induces reorganization in the coordinated activity of the three subdivisions of the trapezius in repetitive dynamic tasks.

Using myoelectric signal parameters to distinguish between computer workers with and without trapezius myalgia

Complaints of chronic trapezius muscle pain among computer workers have increased in prevalence during the last decade. Currently there is no clear understanding of the pathophysiological mechanisms involved in affected muscles. The major objective of this work was to determine if measurable electrophysiological differences exist between the trapezius muscles in individuals suffering from trapezius myalgia (TM) and occupation-matched pain-free control subjects. Myoelectric signal (MES) data were recorded from the upper trapezius muscle while subjects with and without myalgia performed a standardized series of postural and arm-holding tasks. MES variables reflecting muscle fatigue, muscle tension and motor control strategies were analyzed to determine their potential ability to distinguish between the two groups. One variable, RestTime, was found to be significantly different between the groups but it was not specific enough to predict group association. A multivariate logistic regression analysis yielded a model that separated the two groups with better than 70% sensitivity and 70% specificity. The variables included in the model reflect differences in trapezius muscle activity between the groups, particularly related to motor control and/or active muscle tension, but not fatigue. The model was tested using a small sample of new data, which again produced a good sensitivity (85.7%) but not specificity (42.9%). To the authors' knowledge, this is the first objective MES-based model that has successfully classified subjects with or without TM based on a simple clinical test. Further work with this model might result in understanding the pathophysiology of TM, assisting with clinical diagnosis, and testing the effect of various treatment interventions.

Increased levels of interstitial potassium but normal levels of muscle IL-6 and LDH in patients with trapezius myalgia

The mechanisms behind the development of work-related trapezius pain are suggested to involve both peripheral and central components, but the specific contribution of alterations in muscle nociceptive and other substances is not clear. Female patients with chronic trapezius myalgia ( N=19; TM) and female controls ( N=20; CON) were studied at rest, during 20 min repetitive low-force exercise and recovery, and had their interstitial concentrations of potassium (K +), lactate dehydrogenase (LDH), interleukin-6 (IL-6) and collagen turnover determined in the trapezius muscle by the microdialysis technique. K + levels were at all time points higher in TM than in CON ( P<0.0001). Baseline levels of LDH and IL-6 were similar in both groups. In response to exercise pain intensity, rated perceived exertion, and the concentrations of K +, LDH and IL-6 increased significantly in both groups. [K +] immediately decreased to baseline levels in CON but remained elevated during the first 20 min of recovery in TM ( P<0.01) whereafter it returned to baseline level. In all subjects taken together mean [K +] correlated negatively with pressure pain threshold of trapezius ( P<0.001), positively with mean pain intensity VAS ( P<0.001) and mean perceived exertion ( P<0.001). Rises in muscle LDH and IL-6 as well as the anabolic ratio for collagen type I was not significantly different between groups. In conclusion, patients with chronic pain in the trapezius muscle had increased levels of interstitial potassium. This finding could be causally related to myalgia or secondary to pain due to deconditioned muscle or altered muscle activity pattern.

Musculoskeletal Injury- Football

HISTORY A college football quarterback sustained a chest wall injury during a hit that occurred while he scrambled with the ball. During the second quarter of an early season game, he was hit on his right shoulder/neck region with his head laterally bent to the left. He did not present to the trainers with an injury or pain during the game. The next morning he presented at the training room with a chief complaint of right anterosuperior chest wall pain. Pain was worse with inspiration, right arm cocking, anterosuperior chest wall pressure, and left lateral bending. He denied any numbness, tingling, loss of sensation, radiation of pain, weakness, or change in upper extremity temperature or color. There was no neck pain but he did have some mild right trapezius pain. PHYSICAL EXAMINATION He appeared comfortable and in no acute distress. Upper extremity appeared symmetric bilaterally with no evidence of swelling or discoloration. On palpation, he had right-sided chest wall tenderness just inferior to the clavicle. Pain was exacerbated with AP compression of the chest. There was no tenderness over the clavicle or AC joint. Shoulder and arm had full range of motion. He had mild pain with the right arm abducted at 90 degrees and fully externally rotated. His strength was 5/5 and symmetric bilaterally with testing of upper extremity. His light touch sensation was intact in all dermatomes and his radial pulses were 2+ and symmetric. Neck exam revealed no tenderness and full range of motion. Pain increased with left lateral bending and left rotation of the neck. Auscultation of the lungs revealed clear breath sounds which were equal and normal sounding bilaterally. DIFFERENTIAL DIAGNOSIS Chest wall contusion Rib fracture Rib synchondrosis injury Pulmonary contusion Clavicle fracture Sternoclavicular dislocation TESTS AND RESULTS Right rib series radiographs: non-displaced right first rib fracture no clavicle fracture or other bony abnormality Posterior to anterior and lateral chest radiographs: non-displaced right first rib fracture clear lung fields normal cardiac silhouette midline trachea Chest CT scan with three dimensional reformatted images from helical CT scanner unicortical first rib fracture FINAL/WORKING DIAGNOSIS Traumatic isolated unicortical right first rib fracture TREATMENT AND OUTCOMES No contact in practice. Protective equipment modified to increase protection of first rib. Shoulder and neck range of motion and strength exercises. Discussed risks regarding close proximity of important structures. Returned to full contact and was able to start game one week after the initial injury almost completely symptom free.

Musculoskeletal Injury- Football

HISTORY A college football quarterback sustained a chest wall injury during a hit that occurred while he scrambled with the ball. During the second quarter of an early season game, he was hit on his right shoulder/neck region with his head laterally bent to the left. He did not present to the trainers with an injury or pain during the game. The next morning he presented at the training room with a chief complaint of right anterosuperior chest wall pain. Pain was worse with inspiration, right arm cocking, anterosuperior chest wall pressure, and left lateral bending. He denied any numbness, tingling, loss of sensation, radiation of pain, weakness, or change in upper extremity temperature or color. There was no neck pain but he did have some mild right trapezius pain. PHYSICAL EXAMINATION He appeared comfortable and in no acute distress. Upper extremity appeared symmetric bilaterally with no evidence of swelling or discoloration. On palpation, he had right-sided chest wall tenderness just inferior to the clavicle. Pain was exacerbated with AP compression of the chest. There was no tenderness over the clavicle or AC joint. Shoulder and arm had full range of motion. He had mild pain with the right arm abducted at 90 degrees and fully externally rotated. His strength was 5/5 and symmetric bilaterally with testing of upper extremity. His light touch sensation was intact in all dermatomes and his radial pulses were 2+ and symmetric. Neck exam revealed no tenderness and full range of motion. Pain increased with left lateral bending and left rotation of the neck. Auscultation of the lungs revealed clear breath sounds which were equal and normal sounding bilaterally. DIFFERENTIAL DIAGNOSIS Chest wall contusion Rib fracture Rib synchondrosis injury Pulmonary contusion Clavicle fracture Sternoclavicular dislocation TESTS AND RESULTS Right rib series radiographs: non-displaced right first rib fracture no clavicle fracture or other bony abnormality Posterior to anterior and lateral chest radiographs: non-displaced right first rib fracture clear lung fields normal cardiac silhouette midline trachea Chest CT scan with three dimensional reformatted images from helical CT scanner unicortical first rib fracture FINAL/WORKING DIAGNOSIS Traumatic isolated unicortical right first rib fracture TREATMENT AND OUTCOMES No contact in practice. Protective equipment modified to increase protection of first rib. Shoulder and neck range of motion and strength exercises. Discussed risks regarding close proximity of important structures. Returned to full contact and was able to start game one week after the initial injury almost completely symptom free.

Differential Diagnosis and Treatment of Chronic Neck and Upper Trapezius Pain and Upper Extremity Paresthesia: A Case Study Involving the Management of an Elevated First Rib and Uncovertebral Joint Dysfunction

Diagnosis and effective treatment of patients presenting with cervicobrachial symptoms are often challenging due to the large number of potential pain sources and the high degree of convergence of sensory afference in the cervical region. A 42-year-old female presented in the clinic with a six-month history of neck pain, upper trapezius pain, and upper extremity paresthesia. A careful history, specific functional examination, and selected special tests led to diagnosis-specific orthopedic manual therapy management of this patient. The patient fully recovered within 6 physical therapy treatment sessions, which included management of an elevated first rib, double-crush phenomenon, uncovertebral joint dysfunction, and careful ergonomic intervention with home instructions. Although controlled trials are needed to evaluate the effectiveness of these techniques and allow generalizability of such interventions, the recovery of this patient suggests the efficacy of manual techniques and ergonomic intervention in the management of uncovertebral joint dysfunction and thoracic outlet syndrome associated with a double-crush phenomenon.

No release of interstitial glutamate in experimental human model of muscle pain

Glutamate may be released from muscle nociceptors and thereby contribute to mechanisms underlying acute and chronic muscle pain. In vivo concentration of glutamate during muscle pain has not previously been studied in either animals or humans. In the present study, we aimed to study the in vivo concentration of glutamate before, during and after acute pain of trapezius muscle in humans using the microdialysis technique. In addition, we examined the nutritive skeletal muscle blood flow and the interstitial concentrations of lactate, glucose, glycerol, pyruvate and urea. Experimental pain and tenderness were induced by intramuscular infusion of a chemical mixture consisting of bradykinin, prostaglandin E 2, histamine and serotonin. One EMG-needle and one microdialysis catheter were inserted into non-dominant and dominant trapezius muscles on a standard anatomical point in 19 healthy subjects. Dialysates were collected at rest, during infusion and 60 and 120 min after stop of infusion. Local tenderness was recorded at baseline and at the end of experiment. Local pain was recorded during infusion. The infusion of chemical mixture was more painful than infusion of placebo ( p < 0.05) and resulted in significantly higher local tenderness score than placebo ( p = 0.007). There was no difference in change in interstitial concentrations of glutamate, lactate, glucose, glycerol, pyruvate and urea from baseline to infusion and post-infusion periods between chemical mixture and placebo ( p > 0.05). Muscle blood flow increased significantly over time in response to infusion of chemical mixture and placebo ( p = 0.001). However, we found no difference in changes in muscle blood flow between chemical mixture and placebo ( p > 0.05). In conclusion, the present study demonstrates no signs of increased release of glutamate from myofascial nociceptors during and after acute experimentally induced muscle pain and tenderness.

Simultaneous modulation of the exteroceptive suppression periods in the trapezius and temporalis muscles by experimental muscle pain

Objective To investigate whether the exteroceptive suppression (ES) periods in the trapezius and temporalis muscles could be simultaneously modulated by either experimental trapezius muscle pain or temporalis muscle pain. Methods Fourteen healthy volunteers participated in two sessions with randomised injections of either hypertonic or isotonic saline into the right trapezius muscle or right temporalis muscle. The pain intensity was continuously scored on a 10 cm electronic visual analogue scale. During muscle contraction, the early (ES1) and late (ES2) reflex in the temporalis and late (ES2) reflex in the trapezius elicited by electrical stimulation of the right infraorbital nerve were recorded pre-, during-, and post-injection. Results Hypertonic saline injection induced local muscle pain and referred pain with the maximal pain intensity of 6.3±0.5 cm in the right trapezius and 6.7±0.6 cm in the right temporalis muscles. Injection of either hypertonic or isotonic saline into the right trapezius muscle was associated with significantly shortened ES2 duration and offset time in the injected right trapezius muscle. Only injection of hypertonic saline into the right trapezius muscle could significantly reduce the ES2 offset time and decrease the degree of suppression of ES2 in the right temporalis and left trapezius muscles. Injection of either hypertonic or isotonic saline into the right trapezius muscle evoked no changes in ES2 parameters in the left temporalis muscle. Injection of hypertonic saline, but not isotonic saline, into the right temporalis muscle caused a significantly shorter ES2 offset time and shorter ES2 duration bilaterally in the temporalis and trapezius muscles. Conclusions The findings of the present study provide evidence for a bi-directional effects reflecting convergence of muscle afferents from the trigeminal and upper cervical neural systems in humans, which may partly underlie the manifestations of pain referral between these two areas.

Pain and muscular responses to a neural tissue provocation test in the upper limb

Pain and muscular responses to a Neural Tissue Provocation Test with bias to median nerve were examined in 20 asymptomatic subjects. The test was performed on both arms with the cervical spine in a neutral position and in contralateral sideflexion as a sensitizing manoeuvre. The angle of elbow extension at the time of onset of pain and muscle activity in trapezius, biceps and triceps muscles was measured using an electrogoniometer. Muscle activity was recorded by surface electromyography. Results indicate that pain responses and muscle activity of trapezius are present in the majority of normal subjects. The onset of pain was highly reliable and compared favourably with detection of muscle activity onset. There was no significant difference of the angle of the elbow with the onset of pain between arms. Hence in patients with unilateral neck or upper limb pain a difference between sides might be indicative of a possible neural tissue involvement.Pain and muscular responses were influenced by the position of the cervical spine. This finding suggests that cervical contralateral sideflexion has a sensitizing effect on neural tissues. There was an association between the onset of pain and onset of trapezius muscle activity in all painful trials. However, muscle activity was also present in subjects with no pain.

SHOULDER WEAKNESS - GERIATRIC GOLFER

247 HISTORY - An active 73 year old male recreational golfer presented with a chief complaint of right sided neck pain and shoulder weakness of one week duration. The pain started insidiously, was exacerbated by neck movement, and was maximally relieved by rest. He denied antecedent trauma or previous shoulder injury though related a prior history of left cervical radiculopathy twenty years ago. The right shoulder weakness significantly affected his back-swing and was most obvious when he attempted any overhead motions. Furthermore, he reported a vague numbness in the right hand and on rare occasion experienced pain radiating to the right elbow. Additional past medical history included chronic obstructive pulmonary disease, hypothyroidism, hypertension, and an elevated prostate specific antigen(PSA). PHYSICAL EXAMINATION - Neck range of motion (ROM) was full in all planes but precipitated right posterior neck and trapezius muscle pain. On palpation there was minimal cervical paraspinal and shoulder girdle muscle tenderness. Passive right shoulder ROM was normal however, active ROM was limited to 80 degrees of forward flexion and abduction. Shoulder impingement tests were mildly to moderately provocative. Reflexes were normal except for an equivocally reduced right biceps reflex. Manual muscle testing revealed moderate weakness in the right deltoid, biceps and supraspinatus. Sensory examination was normal. Foraminal compression maneuvers were negative. DIFFERENTIAL DIAGNOSIS: Cervical radiculopathy Rotator cuff tendonitis or tear Brachial plexopathy (traumatic, neoplastic, idiopathic) TESTS AND RESULTS: Serology - CBC and sTSH were normal, PSA was highly elevated at 50.9 X-rays cervical spine (with flexion/extension) - Mild degenerative changes with no evidence of instability. MRI cervical spine - No disk herniations or neuroforaminal stenosis. EMG - Consistent with right upper trunk brachial plexopathy. MRI brachial plexus - No evidence of mass lesion or traumatic plexopathy. FINAL/WORKING DIAGNOSIS: Neuralgic Amyotrophy (Idiopathic Brachial Plexopathy) Probable prostate cancer. TREATMENT: Modalities (heat and ice) for pain control as needed. Non-steroidal anti-inflammatory drugs or acetaminophen as needed. Shoulder ROM exercises. Review proper shoulder biomechanics to normalize glenohumeral and scapulothoracic rhythm. Sub-maximal rotator cuff strengthening. Sub-maximal biceps and deltoid strengthening. Recommend Urologic Consultation for prostate evaluation.