Kinanthropometry IX

This is an edited collection of peer-reviewed papers presented at the Ninth International Conference of the Society for the Advancement of Kinanthropometry. Defined as the relationship between human body structure and function, kinanthropometry is an area of growing interest, and these proceedings will be of use to students, academics and professionals in the areas of ergonomics, sports science, nutrition, health, and other allied fields. The assembled works represent the latest research findings across kinanthropometry, moving the discipline forward and promoting good practice and the exchange of expertise

A modular and adjustable ptosis crutch as a non-surgical solution to elevating the upper eyelid of myasthenia gravis patients

Myasthenia Gravis (MG) is a treatable autoimmune disorder that affects the neuromuscular junction. MG is characterised by fatigable muscle weakness of voluntary skeletal muscles with the most commonly affected muscles being the eye and facial muscles. Patients of African genetic ancestry, particularly juveniles, are more likely to develop ocular muscle complications of MG compared to their European counterparts. MG ophthalmoplegic complications include persistent difficulty with moving the eyes and blepharoptosis, despite treatment. Blepharoptosis, or ptosis, describes the condition of a lowered upper eyelid(s), beyond its normal anatomic position. Surgical correction of ptosis is often contraindicated in MG patients with severe weakness of the muscles involved in eye closure and in patients with active disease. In these cases, a non-surgical solution to elevating the ptotic eyelid above the visual axis is required. Objective: To design a patient specific, modular and low cost ptosis crutch to elevate the eyelid(s) of myasthenia gravis patients. The ptosis crutch should be low cost, modular and adjustable in nature. Method: 16 MG patients (42 ± 23 years) volunteered to participate in the pre-design phase of the project. Initial eye measurements of each participant were taken using photographic measurement. A bottomup approach was followed for the design of the ptosis crutch. 3D CAD models of the modular ptosis crutch were created in SolidWorks, according to the measured dimensions and the predefined design parameters. The ptosis crutch was prototyped using 3D printing. Eightyseven design failures were observed before the final design was realised. A design feedback loop lead to the discovery of a device that satisfied the specified requirements. The final ptosis crutch was tested, in the clinical setting, on 12 MG patients (43 ± 24 years). Results: The ptosis crutch was designed to fit onto the superior border of the spectacle frame. The ptosis crutch is adjustable along the x- axis to cater for the inter-individual variability of globe protrusion. The crutch bar is adjusted along the z-axis and elevated the ptotic eyelid by 1.96mm (±1.11mm). All of the participants indicated that they would be interested in using the ptosis crutch on a long-term basis. Conclusion: The immediate feedback on the ptosis crutch from the MG patients has shown a positive outcome for the device. Future work will include obtaining long term feedback on the ptosis crutch from all of the users as well as investigating manufacturing methods using materials with increased durability

Kinanthropometry IX

This is an edited collection of peer-reviewed papers presented at the Ninth International Conference of the Society for the Advancement of Kinanthropometry. Defined as the relationship between human body structure and function, kinanthropometry is an area of growing interest, and these proceedings will be of use to students, academics and professionals in the areas of ergonomics, sports science, nutrition, health, and other allied fields. The assembled works represent the latest research findings across kinanthropometry, moving the discipline forward and promoting good practice and the exchange of expertise

Subject-adjustable computational modelling for the analysis of human head–neck motions in rear-end impacts

Whiplash Associated Disorder (WAD) is a general term used to describe minor injuries to the neck, mostly as a result of a rear-end motor vehicle collision. Although the injury is defined as minor, the long-term symptoms such as neck pain, stiffness, headache, or concentration difficulties, result in high costs to the economy, healthcare services and individuals. Consequently, there has been significant amount of research undertaken to understand and prevent WAD, covering experimental and computational studies. However, whiplash injuries are difficult to detect since diagnostic tools such as X-rays, CT (Computed Tomography) scans or MRI (Magnetic Resonance Imaging) are not suitable to identify the location or the extent of the injury. Also, the injury mechanisms are not fully understood; hence mathematical criteria are used as surrogates to estimate the likelihood of injury. In the present research, a biofidelic, subject-adjustable head-and-neck model (i.e. the model is adjustable for individual subject characteristics) has been developed for rear-end impact whiplash analysis. Existing literature is used to develop the overall research framework (methodology), which has three main objectives: first to explain the importance of personalised protection investigations, second to evaluate the suitability of existing data for a subject-adjustable model, and third to define the required steps in the design of such a model.To generate the geometry of the model, previously published cascading equations capable of predicting the main vertebrae dimensions based on the subject characteristics age, gender and height are used. Also, in line with previous work, seven cervical neck segments represent the seven cervical vertebrae and all surrounding cervical tissues properties. The mass and moment of inertia properties of each segment are lumped into each respective segment. The intervertebral behaviour for two adjacent segments is described by non-linear spring-damper functions, which change according to subject specific characteristics. The model is driven by specification of the first thoracic vertebra (T1) motion.The model combines existing data and methods from different sources, utilising available data in the public domain. New procedures and techniques are incorporated to create a homogeneous model, which is adaptable to a wide range of subjects. The developed computational model is not simply a linear scaling of a master-model to other dimensions, but rather uses prediction equations to create the desired anthropometric model. The anthropometric model predictions for body part dimensions and inertia properties are successfully verified using anthropometric surveys available in the literature.Using lumped and non-linear stiffness and damping equations for the intervertebral joints, and without modelling separate muscles, the model is dynamically calibrated for different experimental sled test data available in the open domain. The joint equations and their coefficients are derived based on published joint data measurements on Post Mortem Human Subjects (PMHS); a scaling of these coefficients is applied to match the overall head-and-neck kinematics of the computational model to the experimental sled test kinematics. For each experimental study, the global head kinematics of the model was calibrated successfully to mimic the head kinematics.The model has been modelled to represent subjects with different anthropometric characteristics, involving a novel relationship between intervertebral joint coefficients and anthropometric subject specifications. The observed effect of each change of anthropometric subject characteristic is evaluated independently using time-history diagrams; then the observed effect of multiple changes of anthropometric subject characteristics is assessed using multi-dimensional response surfaces for the response’s highest magnitude.The analysis of the proposed model has revealed that existing work involving the use of lumped parameter models is not as robust as claimed. This is because existing work has always been evaluated using a low number of validation graphs, i.e. using only the graphs which gave good validation results. The proposed model has been comprehensively evaluated and its limitations are addressed. The developed model had to merge different studies (different ethnical backgrounds, different subject types, etc.) together to create an adjustable model; this is because of the limited available data. The final model is the most homogeneous model currently possible. In addition, there is also limited relevant experimental data for full validation of the model, which is not ideal. Nevertheless, reliable results for the comparison of global head kinematics compared with several experimental sled test studies have been obtained for the average male subject model. Also, using the proposed model the dynamic effects resulting from anthropometric subject differences have been evaluated; these effects are almost perfectly linear relationships for each subject characteristic change. Potential applications for the developed model are the injury assessment based on mathematical whiplash injury criteria, head-restraint optimisation to minimise injury risk and the improvement of neck biofidelity in anthropometric test devices.</div

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 341)

This bibliography lists 133 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during September 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Musculoskeletal shoulder modelling for clinical applications

The shoulder is the most commonly dislocated joint in the human body, with the vast majority of these dislocations being located anteriorly. Anterior shoulder dislocations are commonly associated with capsuloligamentous injuries and osseous defects. Recurrent anterior instability is a common clinical problem and understanding the influence of structural damage on joint stability is an important adjunct to surgical decision-making. Clinical practice is guided by experience, radiology, retrospective analyses and physical cadaver experiments. As the stability of the shoulder is load dependent, with higher joint forces increasing instability, the aim of this thesis was to develop and validate computational shoulder models to simulate the effect of structural damage on joint stability under in-vivo loading conditions to aid surgical decision-making for patients with anterior shoulder instability. The UK National Shoulder Model, consisting of 21 upper limb muscles crossing 5 functional joints, was customised to accurately quantify shoulder loading during functional activities. Ten subject-specific shoulder models were developed from Magnetic Resonance Imaging and validated against electromyographic signals. These models were used to identify the best combination of anthropometric parameters that yield best model outcomes in shoulder loading through linear scaling of personalised shoulder models. These parameters were gender and the ratio of body height to shoulder width (p<0.04) and these model predictions are significantly improved (p<0.02) when compared to the generic model. The forces derived from the modelling were used in two subject-specific finite element models with an anatomically accurate representation of the labrum, to assess shoulder stability through concavity compression under physiological joint loading for pathologies associated with anterior shoulder instability. The key results from these studies were that there is a high risk of shoulder dislocation under physiological joint loading for patients with a 2 mm anterior or 4 mm anteroinferior osseous defect. The loss in anterior shoulder stability in overhead throwing athletes with intact glenoid following biceps tenodesis is compensated by a non-significant increase in rotator cuff muscle force which maintain shoulder stability across all overhead throwing sports, except baseball pitching, where biceps tenodesis has significantly decreased (p<0.02) anterior shoulder stability. The work in this thesis has advanced the technology of musculoskeletal modelling of the shoulder through the inclusion of concavity compression and has applied this to various relevant clinical questions through the further development of an anatomical atlas, and an atlas of tasks of daily living. The applications of such modelling are broader than those addressed here and therefore this work serves as the foundation for potential further studies, including the bespoke design of arthroplasty or other soft tissue procedures.Open Acces

Ergonomics of the Operative Field in Paediatric Minimal Access Surgery

Imperial Users onl