Relationship Between Jaw Muscle Volume and Craniofacial Form

Abstract

To study the relationship between craniofacial form and jaw muscle function, we evaluated 25 adult male subjects with Obstructive Sleep Apnea (age, 30-61 years; weight, 58-122 kg) on the basis of CT scans obtained for routine diagnostic purposes. All scans were obtained with the Frankfort horizontal plane at right angles to the floor; each CT slice was 8 mm thick. Masseter and medial pterygoid muscle outlines were traced, digitized, and stored, and three-dimensional reconstructions were made for calculation of muscle volume. Lateral cephalometric radiographs were analyzed for quantification of selected craniofacial variables. Significant correlations could not be identified between physiological apnea variables and jaw muscle volume. An intersubject variability in masseter muscle volume was identified (range, 22.4-38.1 cm3). Medial pterygoid muscle volume revealed more variability (range, 7.4-15.2 cm3). Masseter muscle volume had a negative correlation with mandibular plane and gonial angle, and a positive correlation with posterior face height, ramus height, posterior face length, condylar center to first molar point length, gonion to pterygomaxillary fissure length, and the ramus height/anterior face height ratio. Medial pterygoid muscle volume showed a positive correlation with posterior face height, ramus height, posterior face length, and the lengths between condylar center to first molar contact point, gonion to pterygomaxillary fissure, and antegonion to key ridge. Subjects with large masseter and medial pterygoid muscle volumes had flat mandibular and occlusal planes, and small gonial angles.

Clinical and magnetic resonance imaging findings of the temporomandibular joint and masticatory muscles in patients with rheumatoid arthritis

“…In this study, the thickness and sectional area measurement of digital images of masseter, lateral pterygoid, and medial pterygoid muscles were obtained by MRI axial sections and no statistical difference was found between the RA and control groups for the muscle thickness and area. The mean sectional area of masseter muscle was found larger than the medial pterygoid muscle as in related articles [30][31][32]. Goto et al [27] found the sectional area in jaw-close position, respectively, as masseter, lateral pterygoid, and medial pterygoid muscle from larger to smaller.…”

Mandibular morphology in two archaeological human skeletal samples from northwest Europe with different masticatory regimes

“…Low mandibular angle has been associated with increased bite force (Ingervall and Helkimo, 1978;Kiliaridis et al, 1995;Raadsheer et al, 1999;Ringqvist, 1973;Sondang et al, 2003;Throckmorton et al, 2000), and greater development of masticatory musculature (Bennington et al, 1999;Bloem and van Hoof, 1971;Gelbke, 1958;Gionhaku and Lowe, 1989;Kasai et al, 1994Kasai et al, , 1997, although some studies have failed to identify such relationships (Charalampidou et al, 2008;Hannam and Wood, 1989;Ingervall and Thilander, 1974;Kitai et al, 2002;Kubota et al, 1998;van Spronson et al, 1991;Watanabe and Watanabe, 2001;Weijs and Hillen, 1986). Gionhaku and Lowe (1989), Kasai et al (1994), Kubota et al (1998) and Bennington et al (1999) associated greater height of the mandibular ramus with increased masticatory muscular development, but Hannam and Wood (1989) and van Spronson et al (1991) failed to detect an association. Maximum bite force was positively associated with ramus height in the studies of Ringqvist (1973), Ingervall and Helkimo (1978) and Raadsheer et al (1999), but not by Ingervall and Thilander (1974), Hannam and Wood (1989) or Watanabe and Watanabe (2001).…”

Relationship between Occlusal Force and Mandibular Condyle Morphology

“…The vertical maxillofacial dimension is thought to be closely related to occlusal force. [3][4][5][6][7][8] The condylar cartilage acts as a regional adaptive growth site during mandibular growth. 9 Absence of the condyles affects the amount of mandibular growth.…”