The superior pterygoid muscle?
D000293:Adolescent; D000328:Adult; D000818:Animals; D004576:Electromyography; D005260:Female; D006801:Humans; D008253:Macaca mulatta; D008297:Male; D008410:Masticatory Muscles / Q000033:anatomy & histology*; D011626:Pterygoid Muscles / Q000033:anatomy & histology* / Q000502:physiology