title: Volume changes in human masticatory muscles between jaw closing and opening.
abstract: Most jaw muscles are complex, multipennate with multiple components. The morphologic heterogeneity of masticatory muscles reflects their functions. We hypothesized that the volume of masticatory muscles changes between jaw closing and opening, and that there is a difference in the volume change among the muscles. Magnetic resonance images of the entire head were obtained in ten normal young adult subjects before and after maximum jaw opening. The volume changes of the masseter, medial, and lateral pterygoid muscles were measured. Only slight changes were seen in the masseter and medial pterygoid muscles. The lateral pterygoid muscle, however, significantly decreased its volume during jaw opening. The results provide normative values of muscle volume in living subjects, and suggest that the volume changes differ among jaw muscles.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. goto@rad.dent.kyushu-u.ac.jp
authors.forename: T K
authors.initials: TK
authors.lastname: Goto
authors.forename: K
authors.initials: K
authors.lastname: Tokumori
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: M
authors.initials: M
authors.lastname: Yahagi
authors.forename: K
authors.initials: K
authors.lastname: Yuasa
authors.forename: K
authors.initials: K
authors.lastname: Okamura
authors.forename: S
authors.initials: S
authors.lastname: Kanda
mesh_terms: D000328:Adult; D019412:Anatomy, Cross-Sectional; D001810:Blood Volume; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007568:Jaw / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008406:Masseter Muscle / Q000033:anatomy & histology* / Q000098:blood supply / Q000502:physiology; D008953:Models, Anatomic; D011626:Pterygoid Muscles / Q000033:anatomy & histology* / Q000098:blood supply / Q000502:physiology; D012016:Reference Values; D018709:Statistics, Nonparametric