• The Journal of Korean Physical Therapy
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• 제26권3호
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• pp.156-162
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• 2014

Purpose: The purpose of this study was to investigate muscle activation related to postural stability depending on different head positions with whole body vibration (WBV) in standing. Methods: Eighteen healthy subjects voluntarily participated in this single-group, repeated-measures study in which the surface electromyography (EMG) data from upper trapezius, rectus abdominis, external oblique abdominis, erector spinae, gluteus maximus, rectus femoris, semitendinosus, medial gastrocnemius were collected over 3 different frequencies (0-10-20Hz) and 4 different head positions (neutral, flexion, extension, chin tuck) for each subject on WBV while standing. Results: The results of this study demonstrated that the EMG activity of all recorded muscles shows significant difference between three different frequencies and four head positions of WBV while standing (p<0.05). In the multiple comparison, significant differences could be observed for most of different frequency conditions except 0-10Hz of RA, 10-20Hz of ST. In contrast, no significant difference showed the comparison of the EMG activity depending on different head positions (p<0.05). Conclusion: These findings suggest that different head positions on WBV do not activate muscles related to postural stability. However, higher frequency on WBV is highly effective to activate whole body muscles included postural muscles regardless of different head positions.

• 한국전문물리치료학회지
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• 제22권1호
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• pp.103-109
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• 2015

Although the relationship between temporomandibular disorder and forward head posture (FHP) is controversial, it is generally accepted that altered head posture can affect mandible position and masticatory muscles activity. Because suprahyoid (SH) and infrahyoid (IH) muscles are stretched by increased passive tension in FHP, this study investigated their activity during mouth opening in FHP compared to neutral head posture (NHP). Twenty healthy subjects (10 males and 10 females) participated in this study. Head postures were evaluated with a cervical range of motion instrument. Electromyography (EMG) activity of bilateral SH and IH muscles was measured while an open mouth was maintained at each head posture. Paired t-test was used to identify significant differences in normalized EMG activity between head postures. Statistical significance was set at .01. Results showed the normalized EMG activity of SH and IH muscles were significantly lower in FHP compared to NHP. This finding indicates that FHP affects the EMG activity of hyoid muscles when they are stretched.

• 대한전자공학회논문지TC
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• 제37권11호
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• pp.32-41
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• 2000

두부 형상이 국내 표준에 근접하는 한 자원자 두부의 MR 및 CT 영상에 바탕하여 새로운 해부학적 두부 모델을 구현하였다. 서로 다른 형상을 갖는 두부의 전자파 비흡수율(SAR)을 비교하기 위해 두 가지의 해부학적 두부 모델의 SAR을 계산하였다. 하나는 구현된 모델이고 다른 하나는 미국 National Library Medicine에서 제작된 흑인 모델이다. 계산 공간 내의 두부와 이동통신단말기는 CENELEC과 FCC 지침의 접촉위치가 되도록 배치하였다. 얻어진 결과로부터 두부의 크기가 작을수록 두부 전체 평균 SAR은 높아짐을 볼 수 있었으나 1g 또는 10g 평균의 국부 SAR은 두부의 크기보다는 외이의 형상에 더 의존하는 것으로 보인다.

• The Journal of Korean Physical Therapy
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• 제30권2호
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• pp.54-57
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• 2018

Purpose: Most studies have reported pain in the head-neck and upper-limbs according to smartphone usage, which is related to the proprioception sense in the head and neck, but there have been few studies. Therefore, the aim of this study was identify the adverse effects of the proprioceptive sense in the head-neck according to smartphone usage. Methods: Twenty-seven young adults (male: 9, female: 18) were enrolled in this study. The proprioceptive sense was measured through the joint reposition sense error and neural positon error in the head-neck during smartphone usage for 0, 5, and 20 minutes. The Noraxon MyoMotion system was used to record the joint position angle and neutral positon in the head-neck. One-way repeated ANOVA was used to identify the differences between the three smartphone use durations and the least-squares difference was used as a post hoc test. The data were analyzed using SPSS 18.0 software. Results: The joint reposition sense error and neural positon error in the head-neck were significantly different among the 0, 5, and 20 minutes of smartphone usage (p<0.05). In the post hoc test, the joint reposition sense error and neural positon error showed a significant difference between smartphone use for 0 minute and 5 minute, and between smartphone use for 0 minute and 20 minutes. Conclusion: This study suggests that smartphone use within 5 minutes can have adverse effects on the proprioceptive sense. Therefore, it is necessary to consider the appropriate use time and break time when using smart phones.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.69-74
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• 2006

Residual stresses are introduced in aluminum cylinder head during quenching at the end of the T6 heat treatment process. Tensile residual stress resulted from quenching is detrimental to fatigue behavior of a cylinder head when it is overlapped with stresses of engine operation load. Quenching simulation has been performed to assess the distribution of residual stress in the cylinder head. Analysis revealed that in-homogeneous temperature distribution led to high tensile residual stress at the foot of the long intake port, where high stresses of engine operation load are expected. Measurements of residual stress have been followed and compared with the calculated results. Results successfully proved that high tensile residual stress, which was large enough to accelerate fatigue failure of the cylinder head, are formed during quenching process at the end of heat treatment at the same critical position. Effect of quenching parameters on the distribution of residual stress in cylinder head has been investigated by choosing different combination of heat treatment parameters. It was demonstrated that changes of quenching parameters led to more homogeneous temperature distribution during cooling and could reduce tensile residual stress at the critical region of the cylinder head used in this study.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권1호
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• pp.41-52
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• 2012

Purpose: Triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline. This point can be fixed as the third point of a triangle with one known side and two known angles. The aim of this study was to find a clinically adaptable method for applying an optical tracking navigation system to orthognathic surgery and to estimate its accuracy of measuring the bone displacement by use of triangulation methods. Methods: In orthognathic surgery, the head position is not fixed as in neurosurgery, so that a head tracker is needed to establish the reference point on the head surface byusing an optical tracking system. However, the operation field is interfered by its bulkiness that makes its clinical use difficult. To solve this problem, we designed a method using an Aquaplast splinting material and a mini-screw in applying a head tracker on a patient's forehead. After that, we estimated the accuracy of measuring displacements of the ball marker by an optical tracking system with a conventional head tracker (Group A) and with a newly designed head tracker (Group B). Measured values of ball markers' displacements by each optical tracking system were compared with values obtained from fusion CT images for an estimation of accuracy. Results: The accuracy of the optical tracking system with a conventional head tracker (Group A) is not suitable for clinical usage. Measured and predictable errors are larger than 10 mm. The optical tracking system with a newly designed head tracker (Group B) shows 1.59 mm, 6.34 mm, and 9.52 mm errorsin threeclinical cases. Conclusion: Most errors were brought on mainly from a lack of reproducibility of the head tracker position. The accuracy of the optical tracking system with a newly designed head tracker can be a useful method in further orthognathic navigation surgery even though the average error is higher than 2.0 mm.

• 대한치과교정학회지
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• 제33권5호
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• pp.323-337
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• 2003

이 연구의 목적은 한국인의 연조직 측모두부방사선학적 기준치를 설정하고, 이를 성별간, 인종간 비교하여, 한국인의 치아안모 변이를 위한 교정적 진단과 치료계획을 확립하기 위한 한 가지 기준을 제안하고자 하는데 있다. 저자들은 균형 잡힌 안모를 가진 젊은 한국인 성 인 남녀 각 27명, 20명을 선발하였다. 이들의 평균연령은 남자 $23.8{\pm}2.6$세, 여자 $22.5{\pm}1.7$세였다. 높은 신뢰성과 재현성을 가진 natural head position에서 측모두부방사선사진을 촬영하였고, 필름을 트레이싱한 뒤 Arnett등이 소개한 분석요소들을 이용하여 계측하였다. 그 결과를 독립 모수 검정을 통하여 한국인 남녀를 우전 비교하였고, 한국인 남녀 각 군을Arnett등이 제시한 백인들의 남녀 기준치와 비교하였다. 그 결과로 부터 다음과 같은 결론을 얻을 수 있었다. 한국인 남자는 한국인 여자보다 전반적으로 비후한 하안모 연조직과 작은 비순각, 긴 안면고경, 깊은 측모상, 그리고 더 돌출된 하안모를 가지고 있었다. Amett등이 제시한 백인 기준치와의 비교에서는 한국인이 남녀 모두에서 덜 노출되는 상악 절치를 제외하고는 전반적으로 더 긴 안면 길이를 보였고, 더 짧은 측모 깊이를 보였다 또한 두 인종 모두 상악 구조물들은 TVL에서부터 유사한 수평적 위치에 있었으나, 한국인 군에서 유의성 있는 상악-하악간 전후방적 거리차를 나타내었다 이는 한국인이 백인에 비해 기준선인 TVL로부터 하악 구조물들이 상대적으로 더 후퇴되어 있음을 의미한다고 할 수 있다. 균형잡힌 안모를 가진 개체의 안면각은 성, 인종에 상관없이 170도 전후를 나타내어 보편적으로 신뢰할 만한 평가항목으로 사료되었다.

• 한국방사선학회논문지
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• 제9권6호
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• pp.331-335
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• 2015

Glenohumeral joint's를 나타내는 단순방사선 촬영법으로 전후사방향 자세에서 촬영하는 Grashey법이 있다. 이 촬영법 자세는 선 자세에서 검사 측을 들어 올리고 촬영한다. 하지만 촬영 시 환자를 몸통을 들어 올리고 회전하는 정도에 따라 관찰범위가 변화한다. Glenohumeral joint's를 가장 잘 나타내기 위한 몸통 회전 각도를 알아보기 위하여 총 20명(남:13명, 여:7명)을 대상으로 촬영을 실시하였으며, 정확한 영상의 판단을 위하여 정형외과 전문의 2명, 방사선사 2명(경력 15년 이상자)이 관찰 평가하였다. 평가의 척도는 Glenohumeral joint's 분리 정도의 점수를 0점은 '분리 안 됨', 1점은 '불량', 2점은 '보통', 3점은 '양호'로 점수를 부여하였다. 몸통 회전 각도를 $30^{\circ}$ 인 영상은 Humerus head와 Glenoid fossa가 겹쳐서 나타났고, $35^{\circ}$ 인 영상에서는 Humerus head와 Glenoid fossa가 약간 겹쳐서 나타났고, $40^{\circ}$ 인 영상에서는 Humerus head와 Glenoid fossa의 관절강이 가장 겹침이 적게 나타났고, $45^{\circ}$ 인 영상에서도 겹침 정도가 많았다. 각 영상의 평가 점수는 $30^{\circ}$는 $0.40{\pm}0.499$, $35^{\circ}$는 $1.34{\pm}0.657$, $40^{\circ}$는 $1.84{\pm}0.573$, $45^{\circ}$는 $0.76{\pm}0.649$로 나타났고 통계적으로 유의한 차이를 나타냈다.(p < .05). 선 자세에서 Glenohumeral joint's를 나타내기 위한 자세에서 환자 몸통을 $40^{\circ}$ 검사 반대 측을 들어 올리고 촬영하였을 경우 우리는 가장 양호한 접시오목(Glenoid fossa)를 나타낼 수 있었다.

• 대한정형도수물리치료학회지
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• 제28권1호
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• pp.39-51
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• 2022

Background: The purpose of this study is to investigate the effect of neck and shoulder self-stretching exercise using audiovisual media on neck pain, postural alignment, and joint position error in women with chronic neck pain. Methods: The subjects included 20 women that gave consent to participate in the study voluntarily. They performed the self-stretching exercises using audiovisual media was carried out 20 minutes 5 times a week during 3 weeks. Neck disability index (NDI) and visual analogue scale (VAS) were used to measure the functional disability and pain, A pressure pain threshold was measured using an algometer, and a cervical range of motion (CROM) measurement tool was used to measure the range of motion and error of proprioceptive position sense of the cervical spine. To assess posture alignment, forward head angle (FHA), forward shoulder angle (FSA) were measured using image J software. Results: The neck pain intensity was statistically significantly within group (p<.05). Neck and shoulder functional disability were a statistically significant difference within group (p<.05). Splenius capitis and upper trapezius pressure pain threshold were statistically significant difference in within group (p<.05). The postural alignment was statistically significantly within group (p<.05). The cervical range of motion in neck extension, right and left lateral flexion were statistically significantly within group (p<.05). The joint position error in neck flexion, extension, right and left lateral flexion decreased statistically significantly within group (p<.05). Conclusion: Self-stretching exercise using audiovisual media increased the mobility of the neck, decreased neck pain and joint position error, and improved posture alignment. As a result, there was a positive effect by applying the self-stretching exercise using audiovisual media to people with neck pain. Based on this, it is thought that it can be used as the basis for research related to home training programs for healthy self-management.

• Radiation Oncology Journal
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• 제37권2호
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• pp.134-142
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• 2019

Purpose: The aim is to study the dependence of deformable based auto-segmentation of head and neck organs-at-risks (OAR) on anatomy matching for a single atlas based system and generate an acceptable set of contours. Methods: A sample of ten patients in neutral neck position and three atlas sets consisting of ten patients each in different head and neck positions were utilized to generate three scenarios representing poor, average and perfect anatomy matching respectively and auto-segmentation was carried out for each scenario. Brainstem, larynx, mandible, cervical oesophagus, oral cavity, pharyngeal muscles, parotids, spinal cord, and trachea were the structures selected for the study. Automatic and oncologist reference contours were compared using the dice similarity index (DSI), Hausdroff distance and variation in the centre of mass (COM). Results: The mean DSI scores for brainstem was good irrespective of the anatomy matching scenarios. The scores for mandible, oral cavity, larynx, parotids, spinal cord, and trachea were unacceptable with poor matching but improved with enhanced bony matching whereas cervical oesophagus and pharyngeal muscles had less than acceptable scores for even perfect matching scenario. HD value and variation in COM decreased with better matching for all the structures. Conclusion: Improved anatomy matching resulted in better segmentation. At least a similar setup can help generate an acceptable set of automatic contours in systems employing single atlas method. Automatic contours from average matching scenario were acceptable for most structures. Importance should be given to head and neck position during atlas generation for a single atlas based system.