scholarly journals Effects of grip force on median nerve deformation at different wrist angles

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2510 ◽  
Author(s):  
Ping Yeap Loh ◽  
Hiroki Nakashima ◽  
Satoshi Muraki

The present study investigated the effects of grip on changes in the median nerve cross-sectional area (MNCSA) and median nerve diameter in the radial-ulnar direction (D1) and dorsal-palmar direction (D2) at three wrist angles. Twenty-nine healthy participants (19 men [mean age, 24.2 ± 1.6 years]; 10 women [mean age, 24.0 ± 1.6 years]) were recruited. The median nerve was examined at the proximal carpal tunnel region in three grip conditions, namely finger relaxation, unclenched fist, and clenched fist. Ultrasound examinations were performed in the neutral wrist position (0°), at 30°wrist flexion, and at 30°wrist extension for both wrists. The grip condition and wrist angle showed significant main effects (p< 0.01) on the changes in the MNCSA, D1, and D2. Furthermore, significant interactions (p< 0.01) were found between the grip condition and wrist angle for the MNCSA, D1, and D2. In the neutral wrist position (0°), significant reductions in the MNCSA, D1, and D2 were observed when finger relaxation changed to unclenched fist and clenched fist conditions. Clenched fist condition caused the highest deformations in the median nerve measurements (MNCSA, approximately −25%; D1, −13%; D2, −12%). The MNCSA was significantly lower at 30°wrist flexion and 30°wrist extension than in the neutral wrist position (0°) at unclenched fist and clenched fist conditions. Notably, clenched fist condition at 30°wrist flexion showed the highest reduction of the MNCSA (−29%). In addition, 30°wrist flexion resulted in a lower D1 at clenched fist condition. In contrast, 30°wrist extension resulted in a lower D2 at both unclenched fist and clenched fist conditions. Our results suggest that unclenched fist and clenched fist conditions cause reductions in the MNCSA, D1, and D2. More importantly, unclenched fist and clenched fist conditions at 30°wrist flexion and 30°wrist extension can lead to further deformation of the median nerve.

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11038
Author(s):  
Kaylyn E. Turcotte ◽  
Aaron M. Kociolek

Background We assessed median nerve travel and deformation concurrently to better understand the influence of occupational risk factors on carpal tunnel dynamics, including forceful chuck gripping and deviated wrist positions. Methods Fourteen healthy right-hand dominant participants performed a chuck grip in 6 experimental conditions: two relative force levels (10% and 40% of maximum voluntary effort); three wrist positions (15° radial deviation, 0° neutral, 30° ulnar deviation). Chuck grip forces were measured with a load cell while the transverse cross-section of the carpal tunnel was imaged via ultrasound at the distal wrist crease. Images of the median nerve were analyzed in ImageJ to assess cross-sectional area, circularity, width, and height as well as travel in the anterior-posterior and medial-lateral axes. Results We found a main effect of deviated wrist position on both anterior-posterior and medial-lateral travel, with the greatest nerve travel occurring in 30° ulnar deviation. There was also a significant interaction between chuck grip force and deviated wrist position on cross-sectional area. Specifically, the area decreased with 40% vs. 10% chuck grip force when the wrist was in 30° ulnar deviation; however, there were no changes in 0° neutral and 15° radial deviation. Discussion Overall, we demonstrated that forceful chuck gripping in deviated wrist positions influenced carpal tunnel dynamics, resulting in both migratory and morphological changes to the median nerve. These changes may, in turn, increase local strain and stress with adjacent structures in the carpal tunnel. Future studies mapping contact stress between structures may further elucidate injury development of work-related carpal tunnel syndrome.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5406 ◽  
Author(s):  
Ping Yeap Loh ◽  
Wen Liang Yeoh ◽  
Hiroki Nakashima ◽  
Satoshi Muraki

Background The objective of this study was to evaluate the changes of the median nerve cross-sectional area (MNCSA) and diameters of the median nerve at different finger postures and wrist angles. Methods Twenty-five healthy male participants were recruited in this study. The median nerve at wrist crease was examined at six finger postures, and repeated with the wrist in 30° flexion, neutral (0°), and 30° extension. The six finger postures are relaxed, straight finger, hook, full fist, tabletop, and straight fist. Results The main effects of both finger postures and wrist angles are significant (p < 0.05) on changes of the MNCSA. Different finger tendon gliding postures cause a change in the MNCSA. Furthermore, wrist flexion and extension cause higher deformation of the MNCSA at different finger postures. Discussion The median nerve parameters such as MNCSA and diameter were altered by a change in wrist angle and finger posture. The results may help to understand the direct biomechanical stresses on the median nerve by different wrist-finger activities.


1993 ◽  
Vol 18 (5) ◽  
pp. 620-623 ◽  
Author(s):  
S. YOSHIOKA ◽  
Y. OKUDA ◽  
K. TAMAI ◽  
Y. HIRASAWA ◽  
Y. KODA

This study evaluated dynamically the morphology of the carpal tunnel during the wrist motion. The object was to determine the transverse dimension (TD), anteroposterior(AP) dimension and cross-sectional area (CA) of the carpal tunnel in the neutral, flexed and extended positions. The wrists of eight male and eight female volunteers aged 20 to 38 years were studied. With wrist extension, AP and CA decreased while the TD increased at the pisiform level, and CA increased at the hamate level. With flexion, TD and CA decreased at the pisiform level and CA decreased at the hamate level. The results showed that the median nerve may be subjected to significant pressure at the pisiform level when the wrist is extended. During wrist flexion, the cross-sectional area decreased at both the level of the pisiform and the hook of the hamate.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 525.1-525
Author(s):  
S. Tsiami ◽  
E. Ntasiou ◽  
C. Krogias ◽  
R. Gold ◽  
J. Braun ◽  
...  

Background:Carpal tunnel syndrome (CTS) is the most common nerve compression syndrome and a common extra-articular manifestation of rheumatoid arthritis (RA). Different causes of CTS are known, among them inflammatory and non-inflammatory pathologies. Electroneurography (ENG) of the median nerve, the method of choice to diagnose CTS, measures impairment of nerve conduction velocity without explaining its underlying cause. However, because the electrical stimulation is often not well tolerated, ENG results may come out inconclusive. Using greyscale ultrasonography (GS-US) provides anatomic information including a structural representation of the carpal tunnel.Objectives:To investigate the performance of nerve GS-US in the diagnosis of CTS in patients with RA.Methods:Consecutive patients with active RA under suspicion of CTS presenting to a large rheumatologic center were included. Both hands were examined by an experienced neurologist including ENG and a GS-US (ML linear probe with 6-15 Hz) of the median nerve. An established grading system for ENG (1), and an established system for GS-US based on cut-offs for the nerve cross sectional area (CSA) [mild: 0,11-0,13cm2, moderate: 0,14-0,15 cm2, severe: > 0,15 cm2 CTS (2)] were used. In addition, the Boston Carpal Tunnel Syndrome Questionnaire (BCTSQ) was used to assess CTS symptoms (3).Results:Both hands of 58 patients with active RA (n=116) and clinical suspicion of CTS (in 38 cases bilaterally) were included. After clinical examination, CTS was suspicious in 96 hands (82.8%), and 59 of all hands had a final diagnosis of CTS (50.9%). Of the latter, 43 hands (72.9%) had a positive ENG and 16 (27.1%) a positive GS-US finding only, while 30 hands (50.8%) were positive in both examinations.There was a good correlation of the cross-sectional area (CSA) as well as the CSA-ratio to the ENG findings: the larger the CSA, the more severe was the CTS as assessed by ENG (Spearman’s rho=0.554; p<0.001). The more severe the GS-US findings of CTS were, the more definite were the distal motor latency (Spearman’s rho=0.554; p<0.001) and sensible nerve conduction velocity of the median nerve (Spearman’s rho=-0.5411; p<0.001).In the 46 hands positive in GS-US, tenosynovial hypertrophy of the flexor tendons was detected in 19 hands (41.3%), 7 of which (36.8%) also showed an additional cystic mass. In these 19 patients, clinical complains were more severely present than in patients with non-inflammatory CTS, as assessed by the BCTSQ with a total score of 68.8±13.4 vs. 59.3±13.7, respectively (p=0.007).Conclusion:In patients with active RA and clinical complains of CTS, ultrasound examinations provide additional information about inflammation which is helpful for a diagnosis of CTS. Thus, ENG and nerve GS-US should be used complementary for a diagnostic workup of CTS in RA patients with a suspicion of CTS. Power-Doppler may further improve the diagnostic performance of GS-US.References:[1]Padua L et al. Acta Neurol Scand 1997; 96:211–217[2]El Miedany et al., Rheumatology (Oxford). 2004 Jul; 43(7):887-895[3]Levine DW et al. J Bone Joint Surg Am 1993; 75: 1585-1592Figure 1.BCTSQ scores in patients with diagnosis of CTS and absence or presence of RA-related tenosynovial hypertrophyDisclosure of Interests:None declared


Diabetology ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 226-231
Author(s):  
Carlos Antonio Guillen-Astete ◽  
Monica Luque-Alarcon ◽  
Nuria Garcia-Montes

Background: Carpal tunnel syndrome is the most prevalent peripheral nerve entrapment condition of the upper limb. Among metabolic risk factors, diabetes is considered the most relevant. Although wrist ultrasound assessment of the median nerve has demonstrated a good correlation with the gold standard for the diagnosis of this syndrome, neurophysiological study, its usefulness in patients with diabetes is questionable because the compressive phenomenon is not the predominant one. Method: We conducted a retrospective study to compare the clinical and median nerve ultrasound features of patients with carpal tunnel syndrome previously diagnosed or not diagnosed with diabetes. Additionally, a linear multivariate regression analysis was performed to determine to what extent the cross-sectional area of the median nerve was dependent on the condition of diabetes by fixing other variables such as sex, age, or time of evolution. Results: We included 303 records of patients (mean age 44.3 ± 11.7 years old, 57.89% female, mean of time of evolution 13.6 ± 8.3 months) from 2012 to 2020. The cross-sectional area of the median nerve was 10.46 ± 1.44 mm2 in non-diabetic patients and 8.92 ± 0.9 mm2 in diabetic patients (p < 0.001). Additionally, diabetic patients had a shorter time of evolution (7.91 ± 8.28 months vs. 14.36 ± 0.526 months, p < 0.001). In the multivariate analysis, the resultant model (fixed R-square = 0.659, p = 0.003) included a constant of the following four variables: the evolution time (Beta coeff. = 0.108, p < 0.001 95% CI 0.091 to 0.126, standardized coeff. = 0.611), the condition of diabetes (Beta coeff. = −0.623, p < 0.001 95% CI −0.907 to −0.339, standardized coeff. = −0.152), the severity (Beta coeff. = 0.359, p = 0.001 95% CI 0.147 to 0.571, standardized coeff. = 0.169), and the masculine sex (Beta coeff. = 0.309, p = 0.003, 95% CI 0.109 to 0.509, standardized coeff. = 0.103). Conclusions: Ultrasound assessment of the median nerve in patients with diabetes is not a useful tool to confirm whether carpal tunnel syndrome should be diagnosed or not diagnosed.


Radiology ◽  
2011 ◽  
Vol 259 (3) ◽  
pp. 808-815 ◽  
Author(s):  
Andrea S. Klauser ◽  
Ethan J. Halpern ◽  
Ralph Faschingbauer ◽  
Florian Guerra ◽  
Carlo Martinoli ◽  
...  

2020 ◽  
Vol 43 (6) ◽  
pp. 654-659
Author(s):  
Jin Sung Park ◽  
Hee-Chan Won ◽  
Jin-Young Oh ◽  
Dong-Hee Kim ◽  
Sun-Chul Hwang ◽  
...  

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