Posture Of Upper Extremity Research Articles

Postures of upper extremity correlated with carpal tunnel syndrome (CTS).

Non-medical hospital staff members are in frequent contact with patients and therefore are required to perform a wide variety of repetitive and high-frequency activities. The objective of this study was to assess the relationships between upper extremity activity and carpal tunnel syndrome (CTS) among non-medical hospital staff members. Carpal tunnel syndrome in 144 non-medical hospital staff members was diagnosed using the Nordic Musculoskeletal Questionnaire (NMQ), a physician's diagnosis, physical examination (Tinel's signs and Phalen test) and a nerve conduction velocity (NCV) test. In addition, an ergonomic assessment was performed and a video camera was used to record the physical activities at work. The prevalence rate of CTS was highest for the NMQ (51.9%), followed by physician's diagnosis (49.5% for the right hand, 29.9% for the left hand), physical examination (54.7%), and nerve conduction test (motor nerve 27.5% and 25%, sensory nerve 21.7% and 15%, for right and left hands, respectively). Based on logistic regression models for the NMQ and physician's diagnoses, there was a dose-dependently higher risk of CTS with the upper extremity index among participants, but this was non-significant based on the physical examination and nerve conduction tests. Nerve conduction velocity is the gold standard in diagnosis of CTS, but use of NMQ and physician's diagnosis may overestimate the incidence of CTS in workers who have been engaging in repetitive stress activities for a relatively short time. Int J Occup Med Environ Health 2017;30(2):281-290.

어깨, 팔꿈치, 손목의 자세에 따른 최대악력과 근육활동에 관한 연구

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 <TEX>$45^{\circ}$</TEX>, <TEX>$90^{\circ}$</TEX>) and postures of shoulder(flexion <TEX>$0^{\circ}$</TEX>, <TEX>$90^{\circ}$</TEX>). 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 <TEX>$0^{\circ}$</TEX>, elbow <TEX>$45^{\circ}$</TEX> and wrist supination. In case of wrist postures, MVC of supination is the highest. In case of elbow and shoulder postures, MVC of flexion <TEX>$45^{\circ}$</TEX> and <TEX>$0^{\circ}$</TEX> 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 <TEX>$45^{\circ}$</TEX>. In case of the angle of shoulder <TEX>$0^{\circ}$</TEX>, elbow <TEX>$45^{\circ}$</TEX> 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 <TEX>$0^{\circ}$</TEX>, elbow flexion <TEX>$45^{\circ}$</TEX> and wrist supination for preventing work-related musculoskeletal disease.