In this study, a three-dimensional finite element (FE) model based on the specific anatomy of a patient presenting a femoroacetabular impingement of the 'cam'-type is developed. The FE meshes of the structures of interest are obtained from arthrographic magnetic resonance images. All soft tissues are considered linear elastic and isotropic, and the bones were assumed rigid. A compression of the femur on the acetabular cavity as well as flexural movements and internal rotations are applied. Stresses and contact pressures are evaluated in this patient-specific model in order to better interpret the mechanism of aggression of the femoral and acetabular cartilages. The corresponding results are presented and discussed. The values obtained for the contact pressures are similar to those reported by other models based on idealised geometries. An FE analysis of a non-cam hip is also performed for comparison with the pathological case.

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RESUMO -Este estudo descreve a construção e validação de uma escala que avalia a perceção dos alunos sobre o seu envolvimento comportamental escolar. Os questionários foram aplicados a 1089 alunos do 6 º, 7 º, 9 º e 10º anos de escolaridade (idade mediana = 13) em Portugal Continental, a partir dos quais foram extraídas duas subamostras aleatórias. Uma subamostra foi submetida a análise fatorial exploratória e a segunda, a uma análise fatorial confirmatória. Emergiram duas dimensões: envolvimento no trabalho acadêmico e participação na aula. A primeira escala revelou uma consistência interna aceitável, revelando-se útil e adequada para avaliar as percepções dos alunos sobre o seu envolvimento comportamental escolar. A segunda dimensão necessita de maior desenvolvimento em futuras investigações.Palavras-chave: estudantes, características dos estudantes, rendimento escolar, modelação de equações estruturais Scale of Student Perceptions Regarding their Behavioral Engagement in School:Construction and Validation ABSTRACT -This study presents the construction and validation of a scale evaluating student perceptions regarding their behavioral engagement in school. The questionnaire was administered to 1089 students attending the 6th, 7th, 9th and 10th grades (median age = 13 years) in Continental Portugal, from which two samples were randomly selected. One of the samples was submitted to exploratory factor analysis; the second sample was submitted to confirmatory factor analysis. Two dimensions emerged: involvement in academic work and class participation. The first scale presented acceptable internal consistency, and is useful and appropriate to evaluate students' perceptions regarding their behavioral engagement in school. The second dimension requires further research and development.