title: [Masticatory muscles. Part V. Geometry of the masticatory muscles and cranial morphology].
abstract: Studies focussed on the interactions between masticatory function and the variation in craniofacial height have received an important impulse by the availability of non-invasive imaging techniques like CT and MRI. These techniques allow for in vivo determination of the cross-sectional area and spatial orientation of the human jaw muscles. In recent MRI studies it has been established that the jaw muscles of long-face subjects are up to 30% smaller than those of normal individuals, while the position of the muscles was fairly comparable in both groups. The maximum bite force of long-face subjects is roughly half that of normals. The observed variation of the in vivo data of normal and long-face jaw muscle geometry does explain only half of the difference in their average maximum bite force. The jaw muscles of long-face and normal subjects are presumably different with respect to their force generating capacity per unit of cross-sectional area, which may be attributed to a different muscle fiber type composition.
authors.affiliation: Vakgroep Orthodontie, Academisch Centrum Tandheelkunde Amsterdam (ACTA), Louwesweg 1, 1066 EA Amsterdam.
authors.forename: P H
authors.initials: PH
authors.lastname: van Spronsen
mesh_terms: D001732:Bite Force; D001827:Body Height; D002508:Cephalometry; D005147:Facial Bones / Q000002:abnormalities*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008410:Masticatory Muscles / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D013577:Syndrome; D014057:Tomography, X-Ray Computed / Q000379:methods; D014716:Vertical Dimension
vernacular_title: Kauwspieren. Deel V. Geometrie van de kauwspieren en schedelmorfologie.