start-ver=1.4 cd-journal=joma no-vol=203 cd-vols= no-issue=1 article-no= start-page=157 end-page=162 dt-received= dt-revised= dt-accepted= dt-pub-year=2012 dt-pub=20120115 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Mechanomyographic activity in the human lateral pterygoid muscle during mandibular movement en-subtitle= kn-subtitle= en-abstract= kn-abstract=The activity of the lateral pterygoid muscle has been regarded to be related to the pathological condition of the temporomandibular joint (TMJ) in the craniomandibular disorders. Because the lateral pterygoid muscle is a deep muscle, a needle electrode is necessary for EMG recordings. The purpose of this study was to establish a non-invasive method for the evaluation of muscle activity of the lateral pterygoid muscle using mechanomyogram (MMG). In three male subjects, surface electromyogram (EMG) in the left masseter muscle, left anterior and posterior belly of the temporal muscle, left anterior belly of the digastric muscle and needle EMG of the inferior head of the lateral pterygoid were recorded during mandibular movement tasks simultaneously with the MMG derived from a condenser microphone in the external ear canal. There were significant positive correlations between the needle EMG signal of the lateral pterygoid muscle and the MMG signal for the tasks of static jaw opened position of 30 mm of interincisal distance (p = 0.000, R(2)=0.725), static jaw opened position of 40 mm of interincisal distance (p = 0.000, R(2) = 0.753), 5 mm protruded mandibular position (p = 0.000, R(2) = 0.653), the most protruded mandibular position (p = 0.000, R(2) = 0803). On the contrary, for the task of maximal clenching, there was no significant correlation between the EMG signal of the lateral pterygoid muscle and the MMG signal. These results suggest that the activity of the lateral pterygoid muscle could be evaluated by the MMG signals recorded in the external ear canal, unless jaw closing major muscles show active contraction. en-copyright= kn-copyright= en-aut-name=KawakamiShigehisa en-aut-sei=Kawakami en-aut-mei=Shigehisa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KodamaNaoki en-aut-sei=Kodama en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MaedaNaoto en-aut-sei=Maeda en-aut-mei=Naoto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SakamotoShunichi en-aut-sei=Sakamoto en-aut-mei=Shunichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=OkiKazuhiro en-aut-sei=Oki en-aut-mei=Kazuhiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=YanagiYoshinobu en-aut-sei=Yanagi en-aut-mei=Yoshinobu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=AsaumiJun-Ichi en-aut-sei=Asaumi en-aut-mei=Jun-Ichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=MaedaTeruta en-aut-sei=Maeda en-aut-mei=Teruta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=MinagiShogo en-aut-sei=Minagi en-aut-mei=Shogo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil= kn-affil=Okayama Univ, Dept Occlusal & Oral Funct Rehabil affil-num=2 en-affil= kn-affil=Okayama Univ, Dept Occlusal & Oral Funct Rehabil affil-num=3 en-affil= kn-affil=Okayama Univ, Dept Occlusal & Oral Funct Rehabil affil-num=4 en-affil= kn-affil=Okayama Univ, Dept Occlusal & Oral Funct Rehabil affil-num=5 en-affil= kn-affil=Okayama Univ, Dept Occlusal & Oral Funct Rehabil affil-num=6 en-affil= kn-affil=Okayama Univ, Dept Oral & Maxillofacial Radiol affil-num=7 en-affil= kn-affil=Okayama Univ, Dept Oral & Maxillofacial Radiol affil-num=8 en-affil= kn-affil=Osaka Dent Univ, Dept Postgrad Clin Training affil-num=9 en-affil= kn-affil=Osaka Dent Univ, Dept Postgrad Clin Training en-keyword=Mechanomyogram kn-keyword=Mechanomyogram en-keyword=Electromyogram kn-keyword=Electromyogram en-keyword=Lateral pterygoid muscle kn-keyword=Lateral pterygoid muscle en-keyword=Jaw movement kn-keyword=Jaw movement END