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J Korean Soc Phys Med, 2015; 10(2): 73-80 http://dx.doi.org/10.13066/kspm.2015.10.1.73 Online ISSN: 2287-7215 Print ISSN: 1975-311X Research Article Open Access 성별에따른몸통근육의초음파영상구조비교 임재헌 최수희 1 서삼기 서남대학교물리치료학과 1 서남대학교작업치료학과 The Comparison of Ultrasound Images on Trunk Muscles According to Gender Jae-Heon Lim, Su-Hee Choi 1, Sam-Ki Seo Department of Physical Therapy, Seonam University 1 Department of Occupational Therapy, Seonam University Received: April 20, 2015 / Revised: April 28, 2015 / Accepted: May 19, 2015 c 2015 J Korean Soc Phys Med Abstract 1) PURPOSE: The purpose of this study is to compare ultrasound images of trunk muscles according to gender in healthy subjects. METHODS: Twenty six subjects(13 males and 13 females) were enrolled in this study. The thickness of trunk muscles was measured for transverse abdominis (TrA), external oblique abdominis (EOA), internal oblique abdominis (IOA), and multifidus (MF) using ultrasound. The thickness of the muscles was measured for the length of cross-section except for fascia. The muscle thickness wasmeasured at the both side, then the mean value was calculated. Also, each of trunk muscle wasanalysed by echodensity, white area index. RESULTS: As a results, there was significant difference in muscle thickness of EOA, IOA according to gender (p<0.05). The male was significant increase than female of EOA, IOA in muscle thickness. There was significant difference in echo intensity of TrA, MF according to gender(p<0.05). The female was significant increase than male of TrA, MF in echo Corresponding Author: hydropt@korea.com intensity. There was significant difference in white area index of EOA according to gender(p<0.05). The female was significant increase than male of EOA in white area index. CONCLUSION: The findings of this study suggest that healthy male have a greater EOA, IOA trunk muscle thickness than female. However, the difference of muscle quality between male and female was showed through thisexperiment. Therefore, the ultrasonography images will be useful tool for seeing quantitative and qualitative difference of trunk muscles according to gender. Key Words: Ultrasonography, Muscle thickness, Echodensity, White area index Ⅰ. 서론몸통근육은허리부위를안정화하는데가장중요한역할을하며, 요통의예방과관리에중요한메시지를준다 (Hodges, 1999). 요통을일으키는요인들중허리근력이높은비중을차지하는데, 근력을알아볼수있는방법은힘을측정하는것이다 (Sung 등, 1999). 근육을

74 J Korean Soc Phys Med Vol. 10, No. 2 직접적으로수축시켜힘의크기를측정할있지만, 초음파를통한단면적이나근두께를파악하여근육의힘향상을알아볼수있다. 근력과단면적, 근두께는밀접한상관관계가있으며 (Chi-Fishman 등, 2004), 등속성및등척성회전력을통한측정근육은단면적이클수록더큰힘을발생시킨다. 그러므로, 더큰힘을발생시키는것인지알아보기위해서초음파를이용하면근육의크기를손쉽게측정해볼수있다. 초음파를사용하면골격근의단면크기를파악하는데도움이되고근육의조직을파악하는데유용한방법이된다 (Emshoff 등, 1999). 또한실시간으로근육을시각화할수있으며휴식하고있을때와움직이고있을때뿐만아니라다른유형으로근육이수축하고있을때에도근육을측정할수있는장점이있다 (Harcke 등, 1988; Rezasoltani 등, 2002). 초음파는척추주변의근육중에서뭇갈래근의진단도구로사용되기도한다 (Hides 등, 1995). 초음파영상을통한근육분석을하게되면근육의양적, 질적특성및신경이나근육병증변화를포함한골격근의병리적문제를파악할수있다 (Maurits 등, 2003). 모든초음파는근육을영상화시킬수있는캘리퍼가장착되어있으므로경계선이구분되며측정이가능하다. 근육의단면적및두께의검사-재검사신뢰도는 0.98~0.99의상관계수를나타내었으며, 근육의 MRI 측정과는상관계수 0.99의상관성을나타내었다 (Pillen 등, 2008; Reeves 등, 2004; Reimers 등, 1998; Sanada 등, 2006). 초음파는사지근육이나골반바닥근육, 가로막근육의비대를측정하는데신뢰성과타당도가입증되었다 (Braekken 등, 2010; Enright 등, 2006). 근두께이외에백색영역지수와근육영상밀도는근육의질적인특성을알아볼수있는측정이다. 근육의상대적인음영강도를평가하기위해객관적인지표로써다른조직들을포함한단면으로관찰하는것이도움이된다 (Heckmatt 등, 1982). 선명하고밝은선이있는근육은훈련이잘된건강한근육이라할수있지만, 손상을받거나문제가있는근육은산만하고뚜렷하지않는특징을보인다. 또한신경근병리정도를알아보는양적인측정은회색조초음파검사 (gray-scale ultraso nography) 가사용되고있다 (Aydinli 등, 2003; Brockmann 등, 2007). 질병과노화에따른몸통근육의구조적변화, 몸통좌우근육의대칭성등을초음파로측정하여알아보는연구가진행되고있으며, 이에더불어성별에따른사지근육의특성을알아본연구들도진행되고있다. 남성 25명, 여성 30명을대상으로안쪽장딴지근육을초음파영상을이용하여성별에따라근두께 (thickness), 근육영상밀도 (echodensity), 백색영역지수 (white area in dex; WAI) 를측정하여알아본결과최대수의적등척성수축과근두께에서성별에따른차이와근육영상밀도와백색영역지수에서성별에따른차이가있는것으로나타났다 (Lee 등, 2007). 건강한참가자를대상으로몸통근두께와대칭성을알아본연구에서남성은여성보다휴식시와수축시배가로근의두께가더크게나타났으며, 특히여성은남성에비해배가로근의비율이더크게나타났다 (Springer 등, 2006). 성별에따른아래등세모근두께의변화를알아본연구에서는남성이여성보다어깨관절 130도벌림위치에서수축시와안정시모두더두껍게나타났다고보고하였다 (Song 등, 2012). 또한나이와성별, 척추수준에따라 273 명의카데바를통해디스크퇴행과의상관성을알아본연구에서는남성의디스크가여성보다퇴행되었다고보고하였다 (Miller 등, 1988). 지금까지연구들을살펴보면, 몸통근두께의성별에따른차이, 대칭성을알아본연구는있었지만몸통근의밀도와백색영역지수를포함한질적특성을함께알아본연구들은이루어지지않았다. 따라서본연구는성별에따른몸통근두께와질적특성인밀도와백색영역지수를분석하여몸통골격근의영상진단학적기초자료를제공하고자한다. Ⅱ. 연구방법 1. 연구대상및연구기간이연구의대상자는건강한성인남녀 26명 ( 남자 13 명, 여자 13명 ) 을대상으로진행하였다. 모든대상자는연구동의서에서명한후실험에참여하였으며, 실험에

성별에따른몸통근육의초음파영상구조비교 75 Table 1.General characteristics of the subjects Male (N=13) Female (N=13) Age (yrs) 24.76±1.01 22.69±0.48 Height (cm) 171.53±7.75 161.38±5.04 Weight (kg) 65.30±13.19 53.03±9.04 Fig 1.The ultrasonography of EOA, IOA, TrA, and MF in trunk muscles. EOA; external oblique abdominis IOA; internal oblique abdominis TrA; transverse abdominis MF; multifidus 참여하기전실험에관한모든사항을상세히전달하였다. 척추에염증이있거나골반및하지의정형외과적질환이있는자, 초음파를적용할부위에상처가있거나복부수술을한과거력이있는자, 현재허리통증이있는자는이연구에서배제한후선발하였다. 대상자의일반적특성은 Table 1에제시하였다. 2. 실험방법 1) 측정도구근육의영상학적측정을위해초음파영상장치 (MyL abone, esoate, Italy) 이용하여근두께, 근육영상밀도, 백색영역지수를측정하였다. 근두께는각근육의횡단면에서근막을제외하고길이 ( mm ) 를측정하였으며, 근육영상밀도는건막이포함되지않도록사각모양을선택하여이곳의평균화소수를정하였다. 백색영역지수는사각모양의선택영역의영상에서화소수가 70이상인부위가백색으로보이는데, 전체화소수 (0~255) 중 17 0이상인부위에서백색으로보이는부분을나눈값으 로하였다. 2) 측정방법각근육별자세는배바깥빗근, 배속빗근, 배가로근을측정할때는바로누운자세에서측정하였고, 뭇갈래근은엎드린자세에서시행하였다. 배바깥빗근, 배속빗근, 배가로근은겨드랑이선에서아래로그은선과배꼽이만나는점에서앞쪽 2.5cm (Ota 등, 2012) 에서측정하였고, 뭇갈래근은허리뼈 4,5번가시돌기사이의바깥쪽 2cm부분에서두께를측정하였다 (Vasseljen 등, 200 6). 모든측정은좌우근육을대상으로측정하였고, 좌우근육의평균을구하였다. 복부의근두께는날숨동안증가될수있기때문에 (Misuri 등, 1997), 복부근육두께의측정은편안한날숨끝지점에서수행되었다. 또한근육의혈액량이근육의크기에영향을줄수있으므로측정전충분한휴식후에측정하였다 (Fig 1). 주파수변조범위는 6~9MHZ 이고, 게인 (gain) 의범위는 20~80 이다. 초음파변환기는배바깥빗근, 배속빗근, 배가로근을측정할때 13MHz ~ 6MHz 선형탐촉자 (linea

76 J Korean Soc Phys Med Vol. 10, No. 2 Table 2. The comparison of trunk muscle thickness according togender Muscle Male Female t P EOA 5.94±1.44 3.77± 0.44 5.22 0.00 IOA 8.10± 1.83 5.69± 0.73 4.40 0.00 TrA 3.42± 0.96 3.53± 0.77-0.32 0.75 MF 24.79±3.42 23.82±2.83 5.22 5.22 EOA; external oblique abdominis IOA; internal oblique abdominis TrA; transverse abdominis MF; multifidus (units : mm) Table 3. The comparison of trunk muscle echodensity according to gender Muscle Male Female t P EOA 116.77±20.62 130.65±18.85-1.79 0.09 IOA 89.88±20.43 101.10±9.08-1.81 0.08 TrA 81.23±17.05 93.17±10.66-2.14 0.04 MF 66.73±13.09 86.88±6.59-4.95 0.00 EOA; external oblique abdominis IOA; internal oblique abdominis TrA; transverse abdominis MF; multifidus r transducer, SL3323) 를사용하였고, 뭇갈래근은10MHz ~ 6MHz의원형탐촉자 (convex transducer, SC3123) 를이용하였다. 특히이완된상태에서초음파의도자가압박하는힘이근육의크기를변화시킬수있으므로충분한양의젤을도자에적용하였다. 근육영상밀도를알아보기위해사각형모양의평균화소수를통해알아볼수있으며, 선택된화소가순수한검정색이면추출된부분의회색조검사의평균값이 0이되고, 순수한흰색이면평균값이 255가된다. 3) 자료분석모든자료는 window용 SPSS 12.0 버전을사용하여분석하였다. 대상자들의일반적특성은기술통계를사용하였으며, 성별에따른몸통근두께, 밀도, 백색영역지수의차이를알아보기위해독립표본 t-검정을사용하여분석하였다. 유의수준 α는 0.05로정하였다. Ⅲ. 연구결과 1. 성별에따른몸통근두께비교성별에따른몸통근두께를비교하기위해독립표본 t-검정을시행한결과배바깥빗근과배속빗근에서남녀간에유의한차이를나타내었다 (Table 2). 배바깥빗근은남성이 5.94±1.44, 여성이 3.77±0.44 이였으며, 배속빗근은남성이 8.10±1.83, 여성이 5.69±0.73 으로남성이여성보다근두께가유의하게두꺼운것으로나타났다 (p<0.05). 배가로근과뭇갈래근은성별에따른유의한차이를나타내지않았다 (p>0.05). 2. 성별에따른근밀도비교성별에따른몸통근밀도를비교하기위해독립표본 t-검정을시행한결과배가로근과뭇갈래근에서남녀간에유의한차이를나타내었다 (Table 3). 배가로근은남성이 81.23±17.05, 여성이 93.17±10.66 이였으며, 뭇갈래근은남성이 66.73±13.09, 여성이 86.88±6.59으로여성이남성보다유의하게높은근밀도를나타냈다 (p<0.

성별에따른몸통근육의초음파영상구조비교 77 Table 4. The comparison of trunk muscle WAI according togender Muscle Male Female t P EOA 0.08±0.07 0.15±0.09-2.26 0.03 IOA 0.02±0.03 0.02±0.02 0.28 0.78 TrA 0.06±0.15 0.02±0.02 0.88 0.38 MF 0.02±0.01 0.02±0.02-0.32 0.75 EOA; external oblique abdominis IOA; internal oblique abdominis TrA; transverse abdominis MF; multifidus WAI; white area index 05). 배바깥빗근과배속빗근은성별에따른유의한차이를나타내지않았다 (p>0.05). 3. 성별에따른백색영역지수비교성별에따른몸통백색영역지수를비교하기위해독립표본 t-검정을시행한결과배바깥빗근에서남녀간에유의한차이를나타내었다 (Table 4). 배바깥빗근은남성이 0.08±0.07, 여성이 0.15±0.09 으로여성이남성보다배바깥빗근에서유의하게높은백색영역지수를나타냈다 (p<0.05). 배속빗근, 배가로근, 뭇갈래근은성별에따른유의한차이를나타내지않았다 (p>0.05). Ⅳ. 고찰이연구에서는정상성인을대상으로몸통안정화에기여하는배바깥빗근, 배속빗근, 배가로근그리고뭇갈래근의초음파영상분석을통해성별에따른몸통근육의구조적특성을비교하고자근두께, 밀도, 백색영역지수를알아보았다. 근두께측정은근육의양적인특성을파악할수있는것으로초음파영상을보면근육조직은어둡게보이지만, 뼈와결합조직은밝게보인다. 초음파영상을통한근두께및디지털영상방법을통한구조적특성을평가하는것은골격근의기능적변화를알아보는데유용한방법이다. 영상을추출할때, 전체를선택하지않고사각형모양만을선택한이유는전체영상을추출한것과값의차이가없을뿐아니라, 전체를알아보는데사각형모양으로추출해도 값에변화가없으며신뢰성이입증되었기때문이다. 몸통근육의크기를알아보기위해측정이용이하고비침습적이며통증없이사용할수있는초음파를사용하여측정하였다. 이에반해자기공명영상은초음파보다해상도가좋으며뭇갈래근과같이초음파로측정하기위해서엎드린자세를취할필요없이바로누운자세에서도가능하나초음파로측정하기위해서는특히뭇갈래근의근두께를측정을하려면엎드린자세를취해야한다. 하지만초음파를사용하면빠른측정이가능하고, 비침습적이며통증없이시행할수있는장점이있으므로본연구에적용하여몸통근육을분석하였다. 이연구의첫번째결과인성별에따른근두께비교에서배바깥빗근과배속빗근은남자가여자보다근두께가유의하게두꺼운것으로나타났지만, 배가로근과뭇갈래근은성별에따른유의한차이를나타내지않았다. 건강한성인남자 55명, 여자 68명총 123명을대상으로성별에따른몸통근육의크기와대칭성을조사한연구에서남성은여성보다근두께가유의하게두꺼운것으로나타났다 (Rankin 등, 2006). 남녀모두배속빗근, 배바깥빗근, 배가로근순으로나타나본연구와일치된결과를나타내었다. 근육두께측정을두가지자세에서측정하였는데, 본연구와측정부위가동일한자세의측정결과에서남성이여성보다배속빗근의상대적근두께가더크게나타나본연구의결과와유사한결과를나타내었다 (Rankin 등, 2006). 절대근크기는남성이여성보다근두께가유의하게더두꺼웠으며, 상대적근크기에서는남녀모두배곧은근, 배속빗근, 배바깥빗근, 배가로근순으로나타나성별에따른차이가있는

78 J Korean Soc Phys Med Vol. 10, No. 2 것으로나타났다. 특히배속빗근의상대적근크기는남성에서더유의하게크게나타나본연구의배속빗근의결과와일치하였다. 배가로근, 배바깥빗근, 배속빗근과성별과의관련성을알아본연구에서남성의배바깥빗근과배속빗근두께는여성보다더두껍다고보고하여본연구의결과와일치하였으나, 배가로근은전체비율에서여성이더높은비율을차지하였다고보고하여본연구의결과와다르게나타났다 (Springer 등, 2006). 체질량지수를정규화하였을때배가로근의근두께는성별에따라차이가없다고하였다 (Rankin 등, 2006). 본연구에서의배가로근의두께가유의한차이를보이지않았던이유는절대적근두께만을비교했기때문으로생각되며, 이는측정한모든근육에서배가로근이차지하는백분율을계산한 Rankin 등 (2006) 의상대적근크기와본연구에서계산한절대근크기와는다른방식으로값을산출했기때문인것으로생각된다. Rank in 등 (2006) 의연구에서상대적근크기를구하는방식으로전체근육에서차지하는배가로근의백분율을서로비교하는연구도필요할것으로생각된다. 건강한대학생을대상으로남녀배곧은근과배빗근의근력을비교한결과여성은남성보다 60% 정도의근력을가지는것으로나타나배빗근에서남성이여성보다더높은근력을나타냈다 (Chen 등, 2012). Hansen 등 (1993) 은성별에따라서로다른몸통근력운동프로그램을통해근력강화시키는근육의비율에차이가있다고보고하였는데, 크기는나이와관련되지않았으며배곧은근이가장두꺼웠으며, 배속빗근, 배바깥빗근, 배가로근순이었다. 본연구에서도근두께는성별에상관없이배속빗근이가장두꺼웠으며, 배바깥빗근, 배가로근순이었다. 성별에따른몸통근육의근밀도비교에서배가로근과뭇갈래근은여자가남자보다유의하게높은근밀도의증가를나타내었지만, 배바깥빗근과배속빗근은성별에따른차이를나타내지않았다. 근육을평가하는데또다른유용한지침은근밀도인데, 건강한근육조직일수록어둡게보인다 (Pillen과 van Alfen, 2011). 근밀도의범위는 0~255인데, 0에가까울수록즉어둡게보이는근육일수록건강한근육이고, 밀도가낮으면낮을수 록근육량이더많다는것을의미한다. 본연구의배가로근과뭇갈래근의근밀도결과에서여성이남성보다유의하게높은근밀도를나타낸것은남성이여성보다두근육의근육량이더많다는것으로추론할수있다. Jeong등 (2006) 은위팔두갈래근의근밀도를알아본결과남녀밀도의차이는 20~29세, 30~59세, 60세이상각연령대에따라성별의차이를나타내어연령에따른변화를확인하였지만, 본연구와동일한연령대인 20~2 9세의위팔두갈래근의근밀도와백색영역지수는차이를나타내지않아 20대의위팔두갈래근의질적특성에서는성별에따른차이가없는것으로나타났다. 연령이증가할수록근섬유가섬유지방조직으로변환되면서근육의반사강도에영향을주어연령이골격근의질적특성에중요변인으로작용하였지만, 동일한연령대에서성별에따른근밀도에서차이가발생하지않았다. 하지만본연구에서동일한연령대의배가로근과뭇갈래근밀도에서남녀간의차이를보인것은심부근육의근육량과지방량의차이가있기때문인것으로사료된다. 성별에다른몸통근육의백색영역지수의비교에서배바깥빗근을제외한나머지근육모두성별에따른차이가나타나지않았다. 배바깥빗근에서남자가여자보다유의하게낮은백색영역지수를나타내었는데, 백색영역지수가낮을수록더어두운것을의미하며어두운것은반사되지않는, 즉지방이나결합조직이아닌근육조직으로구성되면될수록더어둡게보이는것을나타낸다. 근두께가감소할수록흰색을띠게되어백색영역지수가증가한다고보고하였다 (Pillen 등, 2008). 본연구에서근두께는배바깥빗근은남성이여성보다더두꺼우므로여성의백색영역지수가남성보다크다는것을뒷받침한다. 성별에따라근육의양적, 질적특성의차이를본연구를통해제시하였는데, 밀도와백색영역지수는근육내섬유증이나지방조직변화로야기될수있지만섬유증이나지방또는이두가지모두로기인한변화인지는확인하기어려우므로정확한차이를알기위해서는근육조직검사가추가로필요할것으로생각된다.

성별에따른몸통근육의초음파영상구조비교 79 본연구의제한점으로는휴식시성별의두께를비교했으나실제수축시발생하는근육의크기를측정하지못한점과연령이 20대젊은성인이었다는점이다. 또한대상자의표본수가적어일반화하기에는어려움이있다. 추후연구에서는이런부분을보완하여몸통근육의성별에따른휴식시와수축시의근육의질적특성과두께를비교할수있는연구와신경학적질환유무, 연령에따른몸통근육의특성을비교할필요가있을것으로생각된다. Ⅴ. 결론본연구는성별에따른몸통근두께의변화와질적특성을확인하고자하였다. 본연구를통해몸통근두께는배바깥빗근과배속빗근에서남성이여성보다더두꺼웠으며, 근육의질적특성인근육밀도와백색영역지수또한성별에따른차이를나타내었다. 그러므로향후성별에따른몸통근육의양적, 질적차이를알아보는데초음파가유용한도구가될수있을것이다. References Aydinli N, Baslo B, Caliskan M, et al. Muscle ultrasonography and electromyography correlation for evaluation of floppy infants. Brain Dev. 2003;25(1):22-4. Braekken IH, Majida M, Engh ME, et al. Morphological changes after pelvic floor muscle training measured by 3-dimensional ultrasonography: a randomized controlled trial. Obstet Gynecol. 2010;115(2 Pt 1):317-24. Brockmann K, Becker P, Schreiber G, et al. Sensitivity and specificity of qualitative muscle ultrasound in assessment of suspected neuromuscular disease in childhood. Neuromuscul Disord. 2007;17(7):517-23. Chen G, Liu L, Yu J. A comparative study on strength between Americancollege male and female students in caucasian and asianpopulations. Sport Science Review. 2012;21(3-4):153-65. Chi-Fishman G, Hicks JE, Cintas HM, et al. Ultrasound imaging distinguishes between normal and weak muscle. Arch Phys Med Rehabil. 2004;85(6):980-6. Emshoff R, Bertram S, Trobl H. Ultrasonographic crosssectional characteristics of muscles of the head and neck. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1999;87(1):93-106. Enright SJ, Unnithan VB, Heward C, et al. Effect of high-intensity inspiratory muscle training on lung volumes, diaphragm thickness, and exercise capacity in subjects who are healthy. Phys Ther. 2006;86 (3):345-54. Hansen FR, Bendix T, Skov P, et al. Intensive, dynamic back-muscle exercises, conventional physiotherapy, or placebo-control treatment of low-back pain. A randomized, observer-blind trial. Spine (Phila Pa 1976). 1993;18(1):98-108. Harcke HT, Grissom LE, Finkelstein MS. Evaluation of the musculoskeletal system with sonography. AJR Am J Roentgenol. 1988;150(6):1253-61. Heckmatt JZ, Leeman S, Dubowitz V. Ultrasound imaging in the diagnosis of muscle disease. J Pediatr. 1982;101(5):656-60. Hides JA, Richardson CA, Jull GA. Magnetic resonance imaging and ultrasonography of the lumbar multifidus muscle.comparison of two different modalities. Spine (Phila Pa 1976). 1995;20(1):54-8. Hodges PW. Is there a role for transverses abdominis in lumbo-pelvic stability? Man Ther. 1999;4(2):74-86. Jeong JG, Kim KY, Kim JM, et al. Age related analysis of ultrasound images of normal skeletal muscle. Phys Ther Korea. 2006;13(1):47-53. Lee JW, Seo SK, Yoon SW, et al. The architecture characteristics of ultrasonography on the skeletal muscle by gender in normal subject. Journal of coaching development. 2007;9(2):259-67.

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