• Archives of Plastic Surgery
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• v.49 no.6
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• pp.750-754
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• 2022

Trigger wrist, characterized by a clicking or snapping sensation around the wrist joint during finger or wrist motion, and bifid or trifid median nerve, which occurs in carpal tunnel syndrome along with anatomical variation of median nerve, are rare conditions. We report the case of a patient with a thickened tendon caused by severe tenosynovitis and flexor tendon subluxation to the hamate hook due to bowing of the flexor retinaculum, thereby resulting in trigger wrist as well as an anatomical median nerve variation (bifid median nerve in the right wrist and trifid median nerve in the left wrist). A 59-year-old housewife visited our hospital with bilateral fingertip numbness, tingling sensation, and aggravated severe night cramping that began 2 months ago. She also complained about trigger wrist during small finger flexion. Based on magnetic resonance imaging, ultrasonography, and nerve conduction study, trifid median nerve and bilateral severe median nerve neuropathy of the wrist were diagnosed; therefore, transverse carpal tunnel release and exploration under wide-awake anesthesia were planned. Intraoperative findings showed trifid and bifid median nerves in left and right wrists, respectively. Additionally, bowing of flexor retinaculum and severe flexor tendon tenosynovitis were observed. Tenosynovitis with thickened flexor sheath resulted in subluxation of the small finger flexor tendon above the hamate hook. After transverse carpal ligament release with antebrachial fascia release and tenosynovectomy, subluxation of the flexor tendon was resolved. At 6 months postoperatively, the tingling and dullness in fingertips also resolved, and no trigger wrist or any other complications were noted.

• Physical Therapy Korea
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• v.15 no.4
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• pp.43-49
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• 2008

The objective of this study was to compare the differences on the activity and power of the wrist flexors and extensors in subjects before the use of a wrist extension splint, after nighttime wearing of the splint, and after daytime wearing of the splint. Ten healthy male and ten healthy female students (mean: $22.4{\pm}1.2$ years old) volunteered to wear custom-made wrist splints either during the night or during the day, The hand force of the wrist flexor and extensor, and grip force were measured by PowerTrack II and Dynatron, respectively. At the same time, the activities of the wrist flexor and extensor were recorded by' surface electromyography. The maximal hand force and motor unit recruitment of the flexor carpi ulnatis (FCU) increased significantly (p<.05) when tile subjects wore the wrist splints during the daytime, but the maximal hand power of the FCU decreased with nighttime use of the splints. The maximal hand power and motor unit recruitment of the extensor carpi radialis (ECR) and the ECR/FCU ratio decreased both during nighttime and daytime use. The decrement of the ECR/FCU ratio was significant (p<.05). Wearing a wrist extension splint during nighttime led to the maintenance of a lengthened position of the wrist flexor, resulting in the wrist flexor becoming weak. Wearing a wrist extension splint during the day induced the wrist flexors to be greater. In healthy people, the imbalance between the wrist flexors and extensors may be caused by the use of a wrist extension splint. This study indicates that therapists have to consider whether a splint will be effective, as well as the wearing time, when prescribing splints to people with problems of the musculoskeletal system.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.1
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• pp.75-81
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• 2018

Purpose : The aim of this study was to compare the muscle activities of thumb and wrist during unimanual, bimanual symmetric and bimanual reciprocal movements using surface electromyography. Method : Thirty-six participants were involved in this study. Two blocks were used to perform unimanual, bimanual symmetric and bimanual reciprocal movements of thumb and wrist. Muscle activities in the flexor pollicis brevis, abductor pollicis brevis, extensor carpi radialis and flexor carpi radialis were measured using an surface EMG system. Result : For the flexor pollicis brevis and abductor pollicis brevis, significant difference in the muscle activity were found among the unimanual, bimanual symmetric and bimanual reciprocal movement. For the extensor carpi radialis and flexor carpi radialis, the unimanual movement significantly different from the bimanual symmetric and reciprocal movements. Conclusion : Both the thumb and wrist, bimanual symmetric and reciprocal movements were more efficient than the unimanual movement. Moreover, with regard to the thumb, the bimanual reciprocal movement was more efficient than the bimanual symmetric movement.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.3
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• pp.477-485
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• 2010

Purpose : The clinical scale to assess spasticity of muscle was wildly used the modified Ashworth scale (MAS). But reliability of the MAS has been controverted for ambiguity among the grades. The purpose of this study was to establish the inter-rater reliability of the modified MAS (MMAS) translated into Korean in stroke patients. Methods : Twenty-five patients (sixteen men and nine women) with hemiplegia (ten right and fifteen left) were measured by two raters who were physical therapist in the rehabilitation hospital. The raters assessed spasticity of shoulder adductor, elbow flexor, wrist flexor, hip adductor, knee extensor, and ankle plantar flexor in the same patients according to ratings criteria of the MAS and the MMAS. Results : For the inter-rater reliability of the MAS, two raters agreed on 57.3% and the Kappa values were moderate ($\kappa$=0.41) between two rater. The inter-rater reliability of the MAS was fair for the wrist flexor and the hip adductor and moderate for the other muscles. The intra-rater reliability was good for the shoulder adductor and the knee extensor and moderate for the other muscles. For the inter-rater reliability of the MMAS, two raters agreed on 84.7% and the Kappa values were good ($\kappa$=0.78) between two rater. The inter-rater reliability of the MMAS was moderate for the hip adductor, and good for the shoulder adductor and the wrist flexor, and very good for the other muscles. The intra-rater reliability was good for the wrist flexor and the hip adductor and very good for the other muscles. Conclusion : This study suggests that the MMAS translated into Korean is reliable test scale for the spasticity with stroke patients in the clinical field.

• Journal of the Ergonomics Society of Korea
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• v.26 no.3
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• pp.27-33
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• 2007

The purpose of this study was to investigate influence of wrist position on the electromyographic(EMG) activities of the flexor digitorum superficialis (FDS) and extensor digitorum (ED) during drilling and pinch grip. Eighteen healthy subjects had been recruited and each subject performed two tasks (drilling and pinch grip) at three different wrist positions ($30^{\circ}$ flexion, neutral, $30^{\circ}$ extension). The EMG amplitude of each muscle was normalized to the amplitude in the maximal voluntary contraction (MVC). Repeated one-way ANOVA was used to compare the differences of EMG across wrist positions. The FDS EMG activity in both drilling and pinch grip was lowest at $30^{\circ}$ wrist extension and the highest at $30^{\circ}$ wrist flexion. The ED EMG activity was lowest when the wrist was neutral in both tasks. From the results of this study, we can conclude that the desirable wrist positions for drilling and pinch grip tasks are slightly extended or neutral position. Therefore, flexed wrist position should be avoided to reduce the excessive work load on the finger muscles during the tasks.

• The Korean Journal of Physiology
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• v.17 no.1
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• pp.37-43
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• 1983

Electromyographic analysis was made in the forearm to clarify the prime mover of the wrist joint in flexion and extension. Loads of 5 and 10 pounds were given to the hand during isometric and isotonic contraction. The results of this study were summarized as follows: 1) M. flexor carpi ulnaris and m. extensor carpi radialis acted as the prime mover during flexion and extension, respectively, of the wrist joint. 2) The flexor and the extensor of the forearm showed synergistic activities under isotonic contraction, but under isometric contraction the flexor only acted. 3) Muscular activity during the isotonic contraction slightly increased compared with the isometric contraction. 4) EMGs and integrated EMGs were somewhat enhanced as the load increased, but there was no significant difference between 5 and 10 pounds load.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.111-119
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• 2016

This study aimed to analyze postures that were frequently conducted in manufacturing industry. To find grip strength and muscle activities of each posture, Maximum Voluntary Contraction (MVC) and ElectroMyoGraphy (EMG) were measured. Based on the results of this study, the most appropriate posture could be suggested and used as a basic information for preventing musculoskeletal disorders. Most work-related musculoskeletal disorders have been occurred in the fields of manufacturing industry. According to previous studies, it was reported that the rate of musculoskeletal diseases of upper extremity was higher than that of other body parts. Accordingly, there were many studies about discomfort and grip strength of upper extremity. However, these studies dealt with single selection of wrist, elbow and shoulder. So, it was insufficient for comprehensive studies about upper extremity. And in order to improve the work posture, the physiological changes being generated by the combination of wrist, elbow and shoulder postures should be observed and analyzed. In order to conduct this study, thirty university students who had no records of MSDs involved were recruited. Independent variables were postures of wrist(pronation, neutral, supination), postures of elbow(flexion $45^{\circ}$, $90^{\circ}$) and postures of shoulder(flexion $0^{\circ}$, $90^{\circ}$). And dependent variables were MVC values and EMG values. Jamar dynamometer and TeleMyo 2400T G2 was used to measure MVC and EMG. MVC and EMG for 12 postures were measured for three second and for three times. Experiment was performed randomly. A 10 minutes rest period was provided after each t. To measure muscle load, the EMG signals of eight muscles (Biceps, Medial triceps, Lateral triceps, Brachioradialis, Extensor carpi ulnaris, Extensor carpi radialis, Flexor carpi ulnaris and Flexor carpi radialis) were evaluated. MVC values and EMG values were analyzed using Minitab ver. 14. The results showed that MVC value was the highest at shoulder $0^{\circ}$, elbow $45^{\circ}$ and wrist supination. In case of wrist postures, MVC of supination is the highest. In case of elbow and shoulder postures, MVC of flexion $45^{\circ}$ and $0^{\circ}$ was the highest. It was found that there were interaction between wrist and elbow posture under shoulder flexion and between shoulder and wrist under elbow flexion $45^{\circ}$. In case of the angle of shoulder $0^{\circ}$, elbow $45^{\circ}$ and wrist supination, the EMG values of four muscles(Medial Triceps, Extensor carpi ulnaris, Extensor carpi radialis, Flexor carpi ulnaris) were the highest. Based on this study, it is worth to note that the combination postures of upper extremity have a large impact on the MVC and EMG. The optimal condition upper extremity was shoulder flexion $0^{\circ}$, elbow flexion $45^{\circ}$ and wrist supination for preventing work-related musculoskeletal disease.

• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.4
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• pp.739-748
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• 2020

In this study, a wrist protector was manufactured and designed using 3D printing technology to prevent wrist pain when riding a bicycle with a high forward-tilted saddle. The efficiency of the design was analyzed in objective and subjective evaluations. First, seven women in their twenties selected their most preferred design by subjective evaluation from among three 3D wrist protectors. Then electromyography (EMG) was measured and subjective sensations were evaluated while wearing and not wearing the preferred 3D wrist protector as selected by cyclists. Experimental results showed that a wrist-bending angle of 30 degrees was most favored. When the 3D wrist protector was worn, muscle activity was smaller at the flexor carpus radialis position than when the 3D wrist protector was not worn; muscle fatigue was also lower. In the subjective evaluation, the 3D wrist protector was more comfortable than no protector, and wrist fatigue was also lower. In addition, the wrist protector was rated positively for its design suitability, size adequacy, ease of operation, and fit; however, cyclists felt that a little more cushioning was needed.

• Archives of Plastic Surgery
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• v.47 no.3
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• pp.250-255
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• 2020

Background Rosenthal et al. classified female, habitual, non-suicidal wrist cutters as a group and introduced the concept of wrist-cutting syndrome. We investigated the characteristics of wrist-cutting patients at our institution in comparison with results reported previously. Methods We conducted a retrospective study involving 115 patients who had cut their wrists and been examined at the emergency department of a single hospital in Seoul, Korea, between March 2014 and August 2018. Results There were more women (73 patients; 63.5%) than men (42 patients; 36.5%), and the women (mean age, 34.42 years) were significantly younger than the men (mean age, 50.07 years). The patients who had cut their wrists repeatedly were mainly women (22 of 26 patients; 84.6%); however, men caused more severe damage than women. Substance use before a suicide attempt did not significantly increase the severity of wrist cutting. Our institution planned and implemented a suicide prevention intervention program to improve the continuity of outpatient care. The number of patients who continued psychiatric treatment increased significantly after program completion. Conclusions We confirmed that most patients were young women who were not suicidal in the true sense because their wounds were not severe. Our study showed a protective role of the barrier tendons (flexor carpi radialis, palmaris longus, flexor carpi ulnaris), and we suggest careful repair of the barrier tendons to protect neurovascular structures against subsequent cutting events. We found that it was possible to improve the continuity of patient counseling by managing patients through a psychiatric treatment program.

• PNF and Movement
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• v.19 no.3
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• pp.391-399
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• 2021

Purpose: As laptop use increases throughout the COVID-19 pandemic and its use outside of traditional workstations proliferates, it is imperative to expand the limited research available regarding ergonomic exposure. This study aimed to identify the effects of a laptop supporter on biomechanical characteristics in the wrist joint muscles of healthy young adults. Methods: This was a cross-sectional observational study design with thirty-four healthy young adults as participants. They conducted a typing exercise performed under two different conditions, which were with and without a notebook computer supporter. This study measured the biomechanical characteristics of the muscles of the wrist joints including the flexor carpi ulnaris (FCU), the flexor carpi radialis (FCR), the extensor carpi radialis longus (ECRL), and the extensor carpi ulnaris (ECU). Measurements were taken three times: before typing, immediately after typing for 30 minutes with a supporter, and immediately after typing for 30 minutes without a supporter. The statistical method to compare the three different measurement conditions was the repeated measures ANOVA. Results: The participants showed significantly different levels of dynamic stiffness in both the FCU before typing and immediately after 30 minutes of typing with a supporter, and showed significantly different levels of dynamic stiffness in the FCR before typing and immediately after 30 minutes of typing with a supporter. The dynamic stiffness level immediately after 30 minutes of typing without a supporter was significantly different than that immediately after 30 minutes of typing with a supporter. However, the muscle tone was not significantly different among the three different conditions. Conclusion: The results of this study revealed that a laptop supporter used to correct the eye level of the electronic screen increases the dynamic stiffness of the wrist joint flexors, so it is necessary to consider the neutral position of the wrist joint during typing.