Muscle parameters for musculoskeletal modelling of the human neck (original) (raw)
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Stapp car crash journal, 2003
Unlike other modes of loading, the tolerance of the human neck in tension depends heavily on the load bearing capabilities of the muscles of the neck. Because of limitations in animal models, human cadaver, and volunteer studies, computational modeling of the cervical spine is the best way to understand the influence of muscle on whole neck tolerance to tension. Muscle forces are a function of the muscle's geometry, constitutive properties, and state of activation. To generate biofidelic responses for muscle, we obtained accurate three-dimensional muscle geometry for 23 pairs of cervical muscles from a combination of human cadaver dissection and 50(th) percentile male human volunteer magnetic resonance imaging and incorporated those muscles into a computational model of the ligamentous spine that has been previously validated against human cadaver studies. To account for multiple origins, insertions, and lines of action, 82 muscle partition pairs, including nonlinear passive and...
Method of quantitative anatomical study of the dorsal neck muscles
Surgical and Radiologic Anatomy, 1990
Biomechanical models of the cervical spine require knowledge of the position, size and orientation of the individual muscles that act on the cervical spine. We have developed a technique to stereometrically measure anatomical specimens. The apparatus is composed of three graduated metallic rods, which slide along a fixed support. This method is accurate to map the anatomy of individual muscles and provides quantitative data on their lines of action. Results are obtained from one specimen. The computer processing of the collected data allows formulation of a three-dimensional model of the neck muscles in man.
Method of quantitative anatomical study of the dorsal neck muscles. Preliminary study
Surgical and Radiologic Anatomy
Biomechanical models of the cervical spine require knowledge of the position, size and orientation of the individual muscles that act on the cervical spine. We have developed a technique to stereometrically measure anatomical specimens. The apparatus is composed of three graduated metallic rods, which slide along a fixed support. This method is accurate to map the anatomy of individual muscles and provides quantitative data on their lines of action. Results are obtained from one specimen. The computer processing of the collected data allows formulation of a three-dimensional model of the neck muscles in man.
Variation of neck muscle strength along the human cervical spine
Stapp car crash journal, 2004
The aim of this study was to describe and explain the variation of neck muscle strength along the cervical spine. A three-dimensional model of the head-neck complex was developed to test the hypothesis that the moment-generating capacity of the neck musculature is lower in the upper cervical spine than in the lower cervical spine. The model calculations suggest that the neck muscles can protect the lower cervical spine from injury during extension and lateral bending. The maximum flexor moment developed in the lower cervical spine was 2 times higher than that developed in the upper spine. The model also predicted that the neck musculature is 30% stronger in the lower cervical spine during lateral bending. Peak compressive forces (up to 3 times body weight) were higher in the lower cervical spine. These results are consistent with the clinical finding that extension loading of the neck often leads to injuries in the upper cervical spine. Analysis of the model results showed that neck...
Validation of a Dynamic Model of the Neck for Applications in Ergonomics and Functional Assessment
Dyna, 2023
A dynamic neck model is proposed for functional assessment or ergonomic studies using data from conventional biomechanical tools such as video photogrammetry and force platforms. Head and neck inertial parameters are obtained through regression equations and refined through a calibration process to improve accuracy. Head movement is recorded through video photogrammetry, where marker coordinates are used to calculate finite displacements, linear and angular velocities, and accelerations. An inverse dynamics approach estimates the forces and moments at the C7 vertebral level and the generated muscle power. The model was validated through an experimental study with 30 participants, where its estimates were compared to the measurements obtained from a force platform. The comparison aimed to assess the accuracy and reliability of the model. The results show excellent agreement, with a correlation of 0.976 or higher and a standard error of less than 1% of the head weight
European Spine Journal, 2012
Background Computer models and human surrogates used to study the forces and motion of the human neck under various loading conditions are based solely on adult data. Pediatric computer models and dummy surrogates used to improve the safety of children could be improved with the inclusion of previously unavailable pediatric muscle data. Methods Measurements of neck circumference and neck muscle cross-sectional area (CSA) were taken from ten 50th percentile adult male and ten 10-year old male volunteer subjects. Muscle cross-sectional areas were calculated from magnetic resonance images of axial cross-sections of the neck. Results Neck muscle cross-sectional area was calculated for six muscles/muscle groups. A power-law regression analysis was used to describe the relationship between neck circumference and neck muscle cross-sectional area. Conclusions The cross-sectional area and the power-law functions determined by the data in this study provide a means of calculating muscle cross-sectional area for young children, where such data are currently unavailable. This will provide an opportunity to develop more representative pediatric neck models.
Analysis and measurement of neck loads
Journal of Orthopaedic Research, 1988
To examine the loads imposed on the structures of the neck by the performance of physical tasks, a biomechanical model of the neck was constructed. The model incorporated 14 bilateral pairs of muscle equivalents crossing the C4 level. A double linear programming optimization scheme that minimized maximum muscle contraction intensity and then vertebral compression force while equilibrating external loads was used to calculate the muscle contraction forces required and the motion segment reactions produced by task performance. To test model validity, 14 healthy adult subjects performed a series of isometric tasks requiring use of their neck muscles. These tasks included exertions in attempted flexion, extension, and left and right lateral bending and twisting. Subjects exerted maximum and submaximurn voluntary efforts. During the performance, surface myoelectric activities were recorded at eight locations around the periphery of the neck at the C4 level. Calculated forces and measured myoelectric activities were then linearly correlated. Mean measured voluntary neck strengths in 10 male subjects were as large as 29.7 Nm. Four female subjects developed mean strengths that were approximately 60%-90% of those of the males. In both sexes, neck muscle strengths were approximately one order of magnitude lower than previously measured lumbar trunk strengths. Mean calculated neck muscle contraction forces ranged to 180 N. Mean calculated compression forces on the C4-5 motion segment ranged to 1164 N, lateral shear forces ranged to 125 N, and anteroposterior shear forces ranged to 135 N. Correlation coefficients between the calculated muscle forces and the measured myoelectric activities were as large as 0.85 in some muscles, but generally were smaller than this.
Development of a multi-body computational model of human head and neck
2007
Experimental studies using human volunteers are limited to low acceleration impacts while whole cadavers, isolated cervical spine specimens, and impact dummies do not normally reflect the true human response. Computational modelling offers a cost effective and useful alternative to experimental methods to study the behaviour of the human head and neck and their response to impacts to gain insight into injury mechanisms. This article reports the approach used in the development of a detailed multi-body computational model that reproduces the head and cervical spine of an adult in the upright posture representing the natural lordosis of the neck with mid-sagittal symmetry. The model comprises simplified but accurate representations of the nine rigid bodies representing the head, seven cervical vertebrae of the neck, and the first thoracic vertebra, as well as the soft tissues, i.e. muscles, ligaments, and intervertebral discs. The rigid bodies are interconnected by non-linear viscoelastic intervertebral discs elements in flexion and extension, non-linear viscoelastic ligaments and supported through frictionless facet joints. Eighteen muscle groups and 69 individual muscle segments of the head and neck on each side of the body are also included in the model. Curving the muscle around the vertebrae and soft tissues of the neck during the motion of the neck is also modelled. Simulation is handled by the multi-body dynamic software MSC.visuaNastran4D. Muscle mechanics is handled by an external application, Virtual Muscle, in conjunction with MSC.visuaNastran4D that provides realistic muscle properties. Intervertebral discs are modelled as non-linear viscoelastic material in flexion and extension but represented by 'bushing elements' in Visual Nastran 4D, which allows stiffness and damping properties to be assigned to a joint with required number of degrees of freedom of the motion. Ligaments are modelled as non-linear viscoelastic spring-damper elements. As the model is constructed, the cervical spine motion segments are validated by comparing the segment response to published experimental data on the load-displacement behaviour for both small and large static loads. The response of the entire ligamentous cervical spine model to quasi-static flexion and extension loading is also compared to experimental data to validate the model before the effect of muscle stiffening is included. Moreover the moment-generating capacity of the neck muscle elements has been compared against in vivo experimental data. The main and coupled motions of the model segments are shown to be accurate and realistic, and the whole model is in good agreement with experimental findings from actual human cervical spine specimens. It has been shown that the model can predict the loads and deformations of the individual soft-tissue elements making the model suitable for injury analysis. The validation of the muscle elements shows the morphometric values, origins, and insertions selected to be reasonable. The muscles can be activated as required, providing a more realistic representation of the human head and neck. The curved musculature results in a more realistic representation of the change in muscle length during the head and neck motion.