Shoulder posture and median nerve sliding

Prevalence of Lower Back Pain and its Relationship with Driving Postures among Drivers in Taif, Saudi Arabia

Background

Lower back pain (LBP) is well-known as the most common musculoskeletal condition with 80% of lifetime prevalence. The effects of LBP on cultural, social, and public health continue to increase. It brings in billions of dollars of medical costs. This study assessed the prevalence of LBP among car drivers with the wrong driving position in Taif.

Methodology

A cross-sectional study using an electronic questionnaire in English translated to Arabic, which included questions about driving with wrong postures, lower back pain, and its correlation.

Results

91.1% of participants satisfied our inclusion criteria for the data analysis. The prevalence of lower back pain in this study was about 44.1% (n = 659). It was more among those aged >40 years (50.9%) compared to other age groups, which showed a statistically significant association (P < 0.001). It was found that 54.4% (n = 813) had been driving in a wrong posture, and there was a strong association observed between this wrong posture and LBP (51.8%) (P < 0.001).

Conclusion

The prevalence of LBP was high among drivers. This study calls for implanting health education and awareness programs about LBP and its risk factors.

Mechanical Hyperalgesia but Not Forward Shoulder Posture Is Associated with Shoulder Pain in Volleyball Players: A Cross-Sectional Study

Shoulder antepulsion, altered scapular kinematics and imbalance of muscle activity are commonly associated with shoulder pain. This study aimed to observe if there is an association between the forward shoulder angle (FSA) and the pectoralis minor length index (PMI) in volleyball players with and without shoulder pain. Furthermore, this study observed if there is an association between shoulder posture and upper limb mechanical hyperalgesia in volleyball players with and without shoulder pain. Methods: a cross-sectional study was conducted in the Physiotherapy and Pain Research Center in Alcalá de Henares (Spain). A total of 56 volleyball players met the inclusion criteria and agreed to enter the study. Subjects were divided into two groups: shoulder pain group (SPG) and control group (without pain). The following measurements of the dominant sides of the players were collected: FSA, PMI, and pressure pain threshold (PPT) in serratus anterior, lower trapezius, infraspinatus, teres minor, upper trapezius, levator scapulae, pectoralis major, radial nerve, cubital nerve, and median nerve. Results: The Spearman’s Rho revealed no significant correlations were found between FSA and PMI. Moreover, Spearman’s Rho test revealed in the SPG a negative moderate correlation between FSA and Infraspinatus-PPT (Rho = −0.43; p = 0.02); FSA and levator scapulae-PPT (Rho = −0.55; p < 0.01); FSA and pectoralis major-PPT (Rho = −0.41; p = 0.02); PMI and cubital nerve-PPT (Rho = −0.44; p = 0.01). Conclusions: No association was found between the forward shoulder angle and the pectoralis minor index in volleyball players with and without shoulder pain. There is a moderate negative association between shoulder forward angle and muscle mechanical hyperalgesia in volleyball players with shoulder pain, but no such associations were found in volleyball players without shoulder pain. Treatment of the infraspinatus, levator scapulae, pectoralis major, and pectoralis minor muscles could improve shoulder pain and ulnar nerve mechanosensitivity.

Assessing Sciatic Nerve Excursion and Strain with Ultrasound Imaging during Forward Bending

Entrapment neuropathies affecting the sciatic nerve tract may adversely affect neural biomechanical features such as excursion and strain. There is a paucity of in vivo evidence examining the effects of forward bending upon sciatic nerve excursion and strain. The purpose of this study was to assess the reliability of ultrasound imaging in measuring sciatic nerve excursion and strain during forward bending movements. Secondary aims were to quantify sciatic nerve excursion and strain during forward bending movements and to assess the relationship between sciatic nerve excursion and movements of the hip and lumbar spine. The reliability of measuring sciatic nerve excursion was high to excellent whilst measurement of sciatic nerve strain was moderate. The amount of hip flexion, during forward bending, was a strong predictor of sciatic nerve excursion. These findings will support clinicians in the assessment and treatment of entrapment neuropathies, in addition to providing a foundation for future research.

High-resolution ultrasound demonstrates in vivo effects of wrist movement on the median nerve along the forearm

INTRODUCTION/AIMS

High-resolution ultrasound (HRUS) is the imaging method of choice to visualize peripheral nerve size, structure, and biomechanical performance. The purpose of this study was to show and quantify the effects of active and passive wrist alignment on median nerve (MN) cross-sectional area (CSA) along the forearm in a healthy population.

METHODS

Sixteen healthy volunteers underwent HRUS of their dominant forearm (n = 16, 10 males, 6 females, 18-55 y of age). Median nerve's CSA was assessed at four defined areas on the forearm in relation to active and passive wrist alignment.

RESULTS

Changes in wrist alignment were significantly associated with MN CSA (P < .001), regardless if the wrist was moved actively or passively. MN CSA was lowest during passive extension of the wrist joint and highest during passive flexion of the wrist joint (range: 4.5-23.2 mm² ).

DISCUSSION

The elasticity of nerve tissue, the loose connective tissue between the fascicles, and the paraneurium allow peripheral nerves to adapt to longitudinal strain. HRUS enables the demonstration of significant median nerve CSA changes along the forearm during active and passive wrist movement in healthy volunteers.

An exploratory study on the impact of static and dynamic sitting postures on lumbar and pelvic mobility during visual display terminal work

[Purpose] Limited studies exist on the impact of sustained work at a visual display terminal (VDT) on the position and motion of the pelvis and lumbar spine. We evaluated the changes in movement of the lumbar column and pelvis during VDT work. [Participants and Methods] We evaluated the sitting posture of 20 healthy adults while they performed VDT work. The effects of the sitting posture on lumbo-pelvic position and motion were captured using a three-dimensional accelerometer. Between-posture effects of VDT work were evaluated using an analysis of variance (ANOVA). A two-way ANOVA was used to assess the root mean square (RMS) values of the 80-min VDT work period for each posture. A one-way ANOVA was used to evaluate pre- and post-work changes in RMS values during the finger floor distance test (FFD). [Results] People in the dynamic sitting balance chair (DSBC)-based posture demonstrated significantly higher pelvic RMS values than those in reclining and upright sitting postures. The DSBC-based posture was also associated with significantly higher pre- and post-work lumbar and pelvic RMS values during the FFD than in the reclining and upright sitting postures. [Conclusion] The dynamic balance chair may be an effective method of establishing a pattern of spinal exercise during prolonged sitting.

Excursion of the median nerve during a contra-lateral cervical lateral glide movement in people with and without cervical radiculopathy

BACKGROUND

A segmental, contra-lateral cervical lateral glide (CCLG) mobilization technique is effective for patients with cervical radiculopathy (CR). The CCLG technique induces median nerve sliding in healthy individuals, but this has not been assessed in patients with CR.

OBJECTIVE

This study aimed to 1) assess longitudinal excursion of the median nerve in patients with CR and asymptomatic participants during a CCLG movement, 2) reassess nerve excursions following an intervention at a 3-month follow-up in patients with CR and 3) correlate changes in nerve excursions with changes in clinical signs and symptoms.

DESIGN

Case-control study.

METHODS

During a computer-controlled mechanically induced CCLG, executed by the Occiflex™, longitudinal median nerve excursion was assessed at the wrist and elbow with ultrasound imaging (T0) in 20 patients with CR and 20 matched controls. Patients were re-assessed at a 3-month follow-up (T1), following conservative treatment including neurodynamic mobilization.

RESULTS

There was a significant difference between patients and controls in the excursion of the median nerve at both the wrist (Mdn = 0.50 mm; IQR = 0.13-1.30; 2.10 mm (IQR = 1.42-2.80, p < 0.05)) and elbow (Mdn = 1.21 mm (IQR = 0.85-1.94); 3.49 mm (IQR = 2.45-4.24, p < 0.05)) respectively at T0. There was also a significant increase in median nerve excursion at both sites between T0 and T1 in those with CR (Mdn = 1.96, 2.63 respectively). Wilcoxon Signed-Ranks Test indicated median pre-test ranks (Mdn = 0.5, 1.21; Z = - 3.82, p < 0.01; Z = -3.78, p < 0.01 respectively) and median post-test ranks. There was a strong correlation between improvement in median nerve excursion at the elbow at T1 and improvement in pain intensity (r = 0.7, p < 0.001) and functional limitations (r = 0.6, p < 0.01).

CONCLUSION

Longitudinal median nerve excursion differs significantly between patients with CR and asymptomatic volunteers at baseline, but this difference is no longer present after 3 months of conservative physiotherapy management. Improvement in nerve excursion correlates with improvement in clinical signs and symptoms.

Interaction between Pain, Disability, Mechanosensitivity and Cranio-Cervical Angle in Subjects with Cervicogenic Headache: A Cross-Sectional Study

The relationship between the forward head posture and mechanosensitivity in subjects with a cervicogenic headache (CGH) remains uncertain. The aim of the study was to evaluate if there was a relationship between the tissue mechanosensitivity and cranio-cervical angle (CCA) that was moderated by pain intensity and/or disability in subjects with CGH. A convenience sample of 102 subjects was recruited. The CCA was measured with photographs, using a postural assessment software. The pain intensity was measured with a visual analogue scale (VAS), and the disability was measured with the Northwick Park Questionnaire. The pressure pain threshold (PPT) was measured at the spinous process of C2, the upper trapezius and splenius capitis muscles, and the median nerve. Simple moderation multiple regression analyses were constructed. There was a positive relationship between PPT at C2 and CCA, but a nonsignificant relationship for the PPT measured at the muscles and median nerve. The effect of PPT at C2 over CCA was moderated by pain intensity (R² = 0.17; R² change = 0.06; p < 0.05) but not disability. The Johnson–Neyman analysis revealed a cut-off point for the statistical significance of 4.66 cm in VAS. There seems to be a positive relationship between PPT at C2 and CCA, which is positively moderated by pain intensity in subjects with CGH.

In vivo effects of limb movement on nerve stretch, strain, and tension: A systematic review

BACKROUND

The mechanical behavior of the peripheral nervous system under elongation and tension has not been adequately established in vivo.

OBJECTIVE

The purpose of this review is to investigate the mechanical behavior of the peripheral nervous system in vivo.

METHODS

In vivo studies which evaluated the effects of limb movement and neurodynamic tests on peripheral nerve biomechanics were systematically searched in PubMed (Medline), the Cochrane Database, CINAHL, PEDro, Embase and Web of Science. Studies fulfilling the search criteria were assessed for methodological quality with a modified version of the Down & Blacks scale by two reviewers.

RESULTS

This review includes the results of 22 studies, of which 15 examined limb movement influencing the median nerve, four the sciatic nerve, two the tibial nerve; and one each the ulnar and peroneal nerves respectively. Substantial nerve longitudinal and transverse excursion and changes in diameter were reported. Despite this, increased nerve strain was not a major finding.

CONCLUSION

The heterogeneity of included studies, including wide variety of nerves tested, measurement location and joint position prevented comparisons between studies and also amalgamation of data. Limb movement induces complex biomechanical effects of which nerve elongation plays only a minor role.

Association Between Forward Head, Rounded Shoulders, and Increased Thoracic Kyphosis: A Review of the Literature

Objective

The purpose of this review was to explore the association between forward head posture, rounded shoulders, and increased thoracic kyphosis.

Methods

The PubMed, ERIC, and Cochrane databases were searched using the key words posture, head, shoulder, forward scapular posture, and thoracic kyphosis through December 2016.

Results

Our initial search yielded 6840 research studies, 6769 of which were excluded because they either were duplicates or did not satisfy the inclusion criteria. After the abstracts of the remaining studies were read, 15 were assessed for eligibility, and only 4 papers were included in the present review. Cervical lordosis values were found to be significantly associated with thoracic kyphosis values. Also, there were significant correlations between rounded shoulders and increased thoracic kyphosis.

Conclusion

Forward head posture, rounded shoulders, and increased thoracic kyphosis can exist alone or in any combination.

Acute effects of foam rolling on passive tissue stiffness and fascial sliding: study protocol for a randomized controlled trial

Background

Self-myofascial release (SMR) aims to mimic the effects of manual therapy and tackle dysfunctions of the skeletal muscle and connective tissue. It has been shown to induce improvements in flexibility, but the underlying mechanisms are still poorly understood. In addition to neuronal mechanisms, improved flexibility may be driven by acute morphological adaptations, such as a reduction in passive tissue stiffness or improved movement between fascial layers. The aim of the intended study is to evaluate the acute effects of SMR on the passive tissue stiffness of the anterior thigh muscles and the sliding properties of the associated fasciae.

Methods

In a crossover study design, 16 participants will receive all of the following interventions in a permutated random order: (1) one session of 2 × 60 s of SMR at the anterior thigh, (2) one session of 2 × 60 s of passive static stretching of the anterior thigh and (3) no intervention. Passive tissue stiffness, connective tissue sliding, angle of first stretch sensation, as well as maximal active and passive knee flexion angle, will be evaluated before and directly after each intervention.

Discussion

The results of the intended study will allow a better understanding of, and provide further evidence on, the local effects of SMR techniques and the underlying mechanisms for flexibility improvements.

Trial registration

ClinicalTrials.gov, identifier: NCT02919527. Registered on 27 September 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-1866-y) contains supplementary material, which is available to authorized users.

Outcomes following the conservative management of patients with non-radicular peripheral neuropathic pain

STUDY DESIGN

Prospective cohort.

INTRODUCTION

There is limited evidence for conservative management of patients with non-radicular peripheral neuropathic pain (PNP).

PURPOSE

To investigate the effectiveness of a comprehensive treatment approach on pain and disability in patients with non-radicular PNP and to determine if improvements are maintained following the discontinuation of therapy.

METHODS

Patients received a multi-modal therapeutic intervention. Outcome measures were the shortened version of the Disabilities of the Arm, Shoulder and Hand questionnaire (QDASH), Numeric Pain Rating Scale (NPRS), and grip strength. Follow-up data were collected 5 ± 2 months post-discharge.

RESULTS

There was a significant improvement in the QDASH and mean pain (p < .001). There was no significant change in grip strength (p > .13). Follow-up data suggest that pain and disability scores are maintained (p < .001).

CONCLUSION

A comprehensive, conservative treatment program has a positive and lasting effect on pain and disability scores in patients with non-radicular PNP.

LEVEL OF EVIDENCE

IIIa.

Quantitative in vivo longitudinal nerve excursion and strain in response to joint movement: A systematic literature review

BACKGROUND

Neural system mobilization is widely used in the treatment of several painful conditions. Data on nerve biomechanics is crucial to inform the design of mobilization exercises. Therefore, the aim of this review is to characterize normal nervous system biomechanics in terms of excursion and strain.

METHODS

Studies were sought from Pubmed, Physiotherapy Evidence Database, Cochrane Library, Web of Science and Scielo. Two reviewers' screened titles and abstracts, assessed full reports for potentially eligible studies, extracted information on studies' characteristics and assessed its methodological quality.

FINDINGS

Twelve studies were included in this review that assessed the median nerve (n=8), the ulnar nerve (n=1), the tibial nerve (n=1), the sciatic nerve (n=1) and both the tibial and the sciatic nerves (n=1). All included studies assessed longitudinal nerve excursion and one assessed nerve strain. Absolute values varied between 0.1mm and 12.5mm for median nerve excursion, between 0.1mm and 4.0mm for ulnar nerve excursion, between 0.7 mm and 5.2mm for tibial nerve excursion and between 0.1mm and 3.5mm for sciatic nerve excursion. Maximum reported median nerve strain was 2.0%.

INTERPRETATION

Range of motion for the moving joint, distance from the moving joint to the site of the lesion, position of adjacent joints, number of moving joints and whether joint movement stretches or shortens the nerve bed need to be considered when designing neural mobilization exercises as all of these factors seem to have an impact on nerve excursion.

The pattern of tibial nerve excursion with active ankle dorsiflexion is different in older people with diabetes mellitus

BACKGROUND

The peripheral nervous system has an inherent capability to tolerate the gliding (excursion), stretching (increased strain), and compression associated with limb motions necessary for functional activities. The biomechanical properties during joint movements are well studied but the influence of other factors such as limb pre-positioning, age and the effects of diabetes mellitus are not well established for the lower extremity. The purposes of this pilot study were to compare the impact of two different hip positions on lower extremity nerve biomechanics during an active ankle dorsiflexion motion in healthy individuals and to determine whether nerve biomechanics are altered in older individuals with diabetes mellitus.

METHODS

Ultrasound imaging was used to quantify longitudinal motion of the tibial nerve and transverse plane motion of the tibial and common fibular nerves in the popliteal fossa during active ankle movements.

FINDINGS

In healthy individuals, ankle dorsiflexion created mean tibial nerve movement of 2.18 mm distally, 1.36 mm medially and 3.98 mm superficially. When the hip was in a flexed position there was a mean three-fold reduction in distal movement. In people with diabetes mellitus there was significantly less distal movement of the tibial nerve in the neutral hip position and less superficial movement of the nerve in both hip positions compared to healthy individuals.

INTERPRETATION

We have documented reductions in tibial nerve excursion due to limb pre-positioning thought to pre-load the nervous system using a non-invasive methodology. Thus, lower limb pre-positioning impacts nerve biomechanics during ankle motions common in functional activities. Additionally, our findings indicate that nerve biomechanics have the potential to be altered in older individuals with diabetes mellitus compared to younger healthy individuals.

The validity of upper-limb neurodynamic tests for detecting peripheral neuropathic pain

The validity of upper-limb neurodynamic tests (ULNTs) for detecting peripheral neuropathic pain (PNP) was assessed by reviewing the evidence on plausibility, the definition of a positive test, reliability, and concurrent validity. Evidence was identified by a structured search for peer-reviewed articles published in English before May 2011. The quality of concurrent validity studies was assessed with the Quality Assessment of Diagnostic Accuracy Studies tool, where appropriate. Biomechanical and experimental pain data support the plausibility of ULNTs. Evidence suggests that a positive ULNT should at least partially reproduce the patient's symptoms and that structural differentiation should change these symptoms. Data indicate that this definition of a positive ULNT is reliable when used clinically. Limited evidence suggests that the median nerve test, but not the radial nerve test, helps determine whether a patient has cervical radiculopathy. The median nerve test does not help diagnose carpal tunnel syndrome. These findings should be interpreted cautiously, because diagnostic accuracy might have been distorted by the investigators' definitions of a positive ULNT. Furthermore, patients with PNP who presented with increased nerve mechanosensitivity rather than conduction loss might have been incorrectly classified by electrophysiological reference standards as not having PNP. The only evidence for concurrent validity of the ulnar nerve test was a case study on cubital tunnel syndrome. We recommend that researchers develop more comprehensive reference standards for PNP to accurately assess the concurrent validity of ULNTs and continue investigating the predictive validity of ULNTs for prognosis or treatment response.

Measurement of tibial nerve excursion during ankle joint dorsiflexion in a weight-bearing position with ultrasound imaging

BACKGROUND

The ability of peripheral nerves to stretch and slide is thought to be of paramount importance to maintain ideal neural function. Excursion in peripheral nerves such as the tibial can be measured by analysis of ultrasound images. The aim of this study was to assess the degree of longitudinal tibial nerve excursion as the ankle moved from plantar flexion to dorsiflexion in a standardised weight-bearing position. The reliability of ultrasound imaging to measure tibial nerve excursion was also quantified.

METHODS

The tibial nerve was imaged over two separate sessions in sixteen asymptomatic participants in a weight-bearing position. Longitudinal nerve excursion was calculated from a three-second video loop captured by ultrasound imaging using frame-by-frame cross-correlation analysis. Intraclass correlation coefficients (ICC) with 95% confidence intervals (CI) were used to assess the intra-rater reliability. Standard error of the measurement (SEM) and smallest real difference (SRD) were calculated to assess measurement error.

RESULTS

Mean nerve excursion was 2.99 mm SEM ± 0.22 mm. The SRD was 0.84 mm for session 1 and 0.66 mm for session 2. Intra-rater reliability was excellent with an ICC = 0.93.

CONCLUSIONS

Assessment of real-time ultrasound images of the tibial nerve via frame-by-frame cross-correlation analysis is a reliable non-invasive technique to assess longitudinal nerve excursion. The relationship between foot posture and nerve excursion can be further investigated.

Fast template tracking in video sequences

Tracking of poorly defined, rotating and/or distorted objects in a video sequence poses significant problems especially in medical diagnostics including ultrasound (sonographic) video used for examination and diagnosis of internal movement of tissue or muscle and nerve action. Cross-correlation techniques have been successful in retrieving dynamic information directly from ultrasound video data. We outline a fast implementation of tracking based on normalized cross-correlation using an adaptive template and present results from our application, developed in MATLAB™, which successfully tracks arbitrarily selected objects in deformed or severely compromised images. Common ultrasound image evaluation is qualitative but there is need to retrieve quantitative dynamic information such as the trajectory or velocity of selected areas. Our approach uses normalized two-dimensional cross-correlation to find the position of an initially selected template enclosing the feature of interest and map its trajectory frame-by-frame to produce displacement and velocity plots. We illustrate operation of the application using routine ultrasound data and demonstrate its performance using test video of objects rotating full circle and rolling down a ramp. We analyse errors associated with sampling to compare performance of our implementation with a more rigorous but tedious and computationally expensive correlation of a resampled, rotated, and shifted template.

Altered Alignment of the Shoulder Girdle and Cervical Spine in Patients With Insidious Onset Neck Pain and Whiplash-Associated Disorder

Clinical theory suggests that altered alignment of the shoulder girdle has the potential to create or sustain symptomatic mechanical dysfunction in the cervical and thoracic spine. The alignment of the shoulder girdle is described by two clavicle rotations, i.e, elevation and retraction, and by three scapular rotations, i.e., upward rotation, internal rotation, and anterior tilt. Elevation and retraction have until now been assessed only in patients with neck pain. The aim of the study was to determine whether there is a pattern of altered alignment of the shoulder girdle and the cervical and thoracic spine in patients with neck pain. A three-dimensional device measured clavicle and scapular orientation, and cervical and thoracic alignment in patients with insidious onset neck pain (IONP) and whiplash-associated disorder (WAD). An asymptomatic control group was selected for baseline measurements. The symptomatic groups revealed a significantly reduced clavicle retraction and scapular upward rotation as well as decreased cranial angle. A difference was found between the symptomatic groups on the left side, whereas the WAD group revealed an increased scapular anterior tilt and the IONP group a decreased clavicle elevation. These changes may be an important mechanism for maintenance and recurrence or exacerbation of symptoms in patients with neck pain.

Effects of a Visual Feedback Device for Hip Adduction on Trunk Muscles and Sitting Posture in Visual Display Terminal Workers

This study was designed to identify the effects of a visual feedback device for hip adduction on trunk muscles and sitting posture when working at a visual display terminal. The forward head and trunk flexion angles of 20 workers were analyzed using a motion analysis system, and the activities of the lower trapezius, external abdominal oblique, internal abdominal oblique, and L5 paraspinal muscles were analyzed using a electromyography system. The statistical significance of differences between using and not using a visual feedback device was assessed by paired t tests. Using the visual feedback device during Visual Display Terminal work significantly decreased the forward head and trunk flexion angles, and significantly increased the activities of the external abdominal oblique, internal abdominal oblique, and L5 paraspinal muscles. The authors suggest that the visual feedback device for hip adduction promotes the adoption of standard spine and pelvic postures, which might be effective in preventing poor sitting postures.

Significant correlation between autonomic nervous activity and cerebral hemodynamics during thermotherapy on the neck

Although local thermotherapy reduces mental stress and neck stiffness, its physiological mechanisms are still not fully understood. We speculated that local thermotherapy exerts its effect, in addition to its direct peripheral effects, through the central nervous system that is involved in controlling stress responses. In the present study, we investigated the effects of a heat- and steam-generating (HSG) sheet on cerebral hemodynamics and autonomic nervous activity using near-infrared spectroscopy (NIRS) and the electrocardiograms (ECGs). Thirteen healthy young female subjects participated in this study. HSG or simple (control) sheets were repeatedly applied to the neck for 120 s with 180 s intervals of rest between applications. During the experiment, brain hemodynamic responses (changes in Oxy-Hb, Deoxy-Hb, and Total-Hb) and autonomic nervous activity based on heart rate variability (HRV) were monitored. Subjective perception of neck stiffness and fatigue was significantly improved after application of the HSG sheet. NIRS findings indicated that the application of HSG sheets decreased Oxy-Hb concentration in the anterior-dorsal region of the medial prefrontal cortex (adMPFC), while increasing parasympathetic nervous activity and decreasing sympathetic nervous activity. Furthermore, changes in Oxy-Hb in the adMPFC were significantly and negatively correlated with those in parasympathetic nervous activity during application of the HSG sheet. These findings suggest that application of the HSG sheet to the neck region induced mental relaxation and ameliorated neck stiffness by modifying activity of the adMPFC.

Longitudinal sliding of the median nerve in patients with non-specific arm pain

In patients with non-specific arm pain (NSAP; also known as repetitive strain injury), there are clinical signs of altered median nerve sliding. It is possible that a restriction along the nerve course will lead to abnormal increases in local strain during limb movements, possibly contributing to symptoms. The present study uses ultrasound imaging to examine median nerve sliding through the proximal and distal nerve segments in 18 NSAP patients. Longitudinal nerve sliding was measured during metacarpophalangeal, wrist and elbow movements. During elbow movements, the angle of elbow extension at which the nerve begins to move was determined, since this was expected to decrease with a restriction through the shoulder. The results from this study were compared with previously reported data. Nerve movements ranged from 1.26 to 4.73 mm in patients compared with 1.43-5.57 mm in controls. There was no significant difference in nerve sliding (p>0.05) or in the angle of elbow extension at which the nerve began to move (mean=53.4 degrees in patients, 52.0 degrees in controls; p>0.05). In summary, restriction of median nerve sliding is unlikely to play a major role in NSAP. Therefore, painful responses during limb movements which tension the nerve are unlikely to result from abnormal increases in nerve strain.

Effects of the height of ball-backrest on head and shoulder posture and trunk muscle activity in VDT workers

This study was designed to elucidate the effects of a ball-backrest at different heights on the head and shoulder posture and neck and trunk muscles of visual display terminal (VDT) workers who adopted a forward head posture when working at a VDT. Twenty-three VDT workers with forward head posture performed the keyboard typing work at a VDT without and with a ball-backrest at the L3, T10, and T4 levels. Surface electromyograms were recorded from the neck, shoulder, and trunk muscles, and the forward head angle and forward shoulder angle were analyzed using a 3-D motion analysis system. The significance of differences for the ball-backrest at different heights was tested by repeated one-way ANOVA, with the significance cutoff set at p=0.05. The mean forward head angle and forward shoulder angle decreased in the order of no backrest, T10-level ball-backrest, T4-level ball-backrest. Compared with not using a backrest, the activity of midcervical muscles was significantly lower and that of the lower trapezius was significantly higher when using a T4-level ball-backrest, and the activity of the internal oblique abdominal muscle was significantly higher when using a T10-level ball-backrest. We suggested that using T4 and T10-level ball-backrests would produce similar effects to active exercise, such as ball exercise for trunk stabilization, and that a ball-backrest would prevent kinematics changes. Therefore, the height of the backrest must be determined on the basis of the characteristics of work-related musculoskeletal disorders when applying a ball-backrest to VDT workers with such disorders.

The double crush syndrome: a common occurrence in cyclists with ulnar nerve neuropathy-a case-control study

OBJECTIVE

To evaluate the incidence of double crush syndrome in the upper limbs of cyclists with clinical diagnosis of ulnar nerve neuropathy.

DESIGN

Case-control study.

SETTING

Outpatient clinics and university setting.

PARTICIPANTS

Consecutive sampling of 70 cyclists (140 upper limbs) with a mean age of 36 years (+/-11.3). Seventy-two upper limbs were excluded, leaving 40 upper limbs with a clinical diagnosis of ulnar nerve neuropathy [ULNN (+)] and 28 without symptoms of ulnar nerve neuropathy [ULNN (-)].

ASSESSMENT

Cyclists were examined clinically for the presence of proximal dysfunction using the following testing (independent variables): (1) thoracic outlet syndrome provocation testing: elevated arm stress test and modified Cyriax release test; (2) presence of an elevated first rib: cervical rotation lateral flexion test; and (3) presence of proximal symptoms: reports of neck pain and shoulder pain.

MAIN OUTCOME MEASUREMENTS

The upper limbs of cyclists were categorized into 2 groups (dependent variable)-ULNN (+) and ULNN (-)-based on history, symptoms, motor, sensory, and provocative clinical testing.

RESULTS

A significantly greater number of upper limbs of cyclists with ULNN (+) presented with positive provocative testing for thoracic outlet syndrome (elevated arm stress test P = 0.005; modified Cyriax release test P = 0.002) than did the upper limbs of cyclists with ULNN (-). The likelihood for the presence of neck pain, shoulder pain, and an elevated first rib was 3, 5, and 12 times greater, respectively, in the ULNN (+) than the ULNN (-) group.

CONCLUSION

A statistically significant greater number of the upper limbs of cyclists with clinical diagnosis of ulnar nerve neuropathy presented with proximal dysfunctions suggestive of double crush syndrome.

Effects of a proximity-sensing feedback chair on head, shoulder, and trunk postures when working at a visual display terminal

INTRODUCTION

This study was designed to identify the effects of feedback from a proximity-sensing chair on head, shoulder, and trunk postures when working at a visual display terminal (VDT).

METHODS

Twenty healthy adults were asked to perform VDT work, and their forward head, forward shoulder, and trunk flexion angles were analyzed using a 3-D motion analysis system. The statistical significance of differences between without and with an auditory feedback device was tested by paired t-tests, with the significance cutoff set at alpha=0.05.

RESULTS

The forward head, forward shoulder, and trunk flexion angles significantly decreased during VDT work when using the proximity sensor with auditory feedback.

CONCLUSION

We suggest that a feedback device promotes the adoption of beneficial postures, which may be effective in preventing VDT-work-related neck and upper-limb disorders.