title: Neck Muscle Moment Arms Obtained In-Vivo from MRI: Effect of Curved and Straight Modeled Paths.
abstract: Musculoskeletal models of the cervical spine commonly represent neck muscles with straight paths. However, straight lines do not best represent the natural curvature of muscle paths in the neck, because the paths are constrained by bone and soft tissue. The purpose of this study was to estimate moment arms of curved and straight neck muscle paths using different moment arm calculation methods: tendon excursion, geometric, and effective torque. Curved and straight muscle paths were defined for two subject-specific cervical spine models derived from in vivo magnetic resonance images (MRI). Modeling neck muscle paths with curvature provides significantly different moment arm estimates than straight paths for 10 of 15 neck muscles (p < 0.05, repeated measures two-way ANOVA). Moment arm estimates were also found to be significantly different among moment arm calculation methods for 11 of 15 neck muscles (p < 0.05, repeated measures two-way ANOVA). In particular, using straight lines to model muscle paths can lead to overestimating neck extension moment. However, moment arm methods for curved paths should be investigated further, as different methods of calculating moment arm can provide different estimates.
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, WA, 99164, USA.
authors.forename: Bethany L
authors.initials: BL
authors.lastname: Suderman
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, WA, 99164, USA. vasavada@wsu.edu.|Gene and Linda Voiland School of Chemical and Bioengineering, Washington State University, Pullman, WA, 99164-6515, USA. vasavada@wsu.edu.|Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA, 99164, USA. vasavada@wsu.edu.
authors.forename: Anita N
authors.identifier: 0000-0003-2537-9590
authors.initials: AN
authors.lastname: Vasavada
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D002574:Cervical Vertebrae / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology*; D009334:Neck Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019415:Torque
keywords: Curved muscle path; Moving muscle points; Musculoskeletal model; Neck muscles