The finite element modeling of human pelvis and its application in medicolegal expertise / 法医学杂志

OBJECTIVE@#To develop a novel three dimensional finite element(FE) model of the human pelvis and investigate the biomechanics of the pelvic injury and explore the applications of FE approach in forensic medicine.@*METHODS@#The FE model of pelvis including bilateral iliac bones, sacrum, bilateral femurs, joint cartilages and ligaments was developed with Mimics 13.1 based on the CT images. The CT value of material properties were assigned. A static pressure of 600 N was applied at the upper surface of the sacrum endplate downwards along the vertical axis of sacral bone to validate the model. To simulate the side impacts, the lateral forces of 1, 2, 3, 4 and 5 kN were applied to the trochanter surface of right femur, respectively. The von Mises stress contours, displacement contours and stress distribution curves were subsequently calculated.@*RESULTS@#An integrated FE model of pelvis including the joint cartilages and ligaments was successfully established. The model geometry coincided well with the CT images. The stress distributions of pelvis in erect position mainly located near the sacroiliac joints and the greater sciatic notches. Stress concentration was found on the superior and inferior pubis ramus, hip and sacroiliac joints on both sides under side impacts.@*CONCLUSION@#The established FE model has accurate and reliable biomechanical features. The FE model can be used to simulate injury and provide intuitive and accurate evidence for medicolegal expertise.

Biomecánica del pie / Foot biomechanics

El hombre en bipedestación siempre se halla en continuo movimiento, por lo que la posición de reposode pie es sólo teórica. 2. En un pie normal, el 80 por ciento de la carga va hacia el talón y un 20 por ciento al antepié. 3. Todas las cabezas metatarsianas soportan carga, pero la cabeza del 1º recibe el doble o más que las restantes. 4. La divergencia de los MTT está limitada por:la arquitectura de la articulación de Lisfranc. La acción de los ligamentos transversos de la planta. La acción de los músculos y tendones (tibial posterior y peroneo por detrás, fascículo transverso del abductor por delante).5. la situación en el plano transversal de las cabezas metatarsianas viene condicionada por la articulación de Lisfranc: con pie en descarga forman un arco anterior; con carga se hallan horizontales. 6. Durante la reflexión dorsal del dedo gordo, gracias al dispositivo glenosesamoideo, la cabeza del 1er MTT rueda sin avanzar. En las demás articulaciones MTT-F, la cabeza, al girar, se translada hacia delante, con lo que se "apelotonan en martillo" las falanges de los respectivos dedos. 7. Los músculos extensores de los dedos no tienen como misión la flñexión dorsal de éstos, sino la de levantar el pie, impidiendo que caiga durante la face oscilante de la marcha. Su función es más tensora que extensora. 8. Los músculos interóseos y lumbricales sirven para solidarizar el dedo al metatarsiano durante la flexión dorsal del pie.10. En la mayoría de los casos (70 por ciento), durante la fase de apoyo de la marcha, el pie pasa sucesivamente por las siguientes posiciones: 1º, choque del talón; 2º, apoyo del talón y del antepié; 3º, apoyo sólo del antepié; 4º, despegue por la cabeza del 1er MTT y dedo gordo. 11. Durante la deambulación normal el pie apenas se apoya por su parte media. 12. El simple hecho de llevar taco alto, al desequilibrar el antepié, puede ser causa de dolor en el mismo. 13. Grados ligeros de retracción del tendón de Aquiles, que no llegan a alterar la forma del pie, pueden ser causa de metatarsalgia.14. En la mayor parte de los casos, las deformaciones de los dedos (allux valgus, en garra, enmartillo, etc.) son la traducción anterior y más aparente de undesarreglo biomecánico de una porción más posterior del metatarso o del tarso

Hyoepiglottic ligament (a morphological study and functional considerations)

We have analyzed 56 larynx from male and female adult human cadavers by dissection. Twenty-seven were non-fixed and twenty-nine fixed with formaldehyde. Sixteen non-fixed larynges were also histologically studied. We have observed a fibrous trapezoidal structure linking the hyoid bone to the epiglottis with a transverse and laminar characteristic. This structure has a larger insertion on the hyoid extremity and besides its midline region is thicker than its sides. This fibrous band connects the hyoid bone cranially, with the epiglottis caudally, following an oblique direction. Histologically this fibrous structure is formed by collagenous and elastic tissue. There are more collagenous tissue on the hyoid extremity. Analyzing the relations and morphology of the hyoepiglottic ligament we have concluded that this strong ligament should be considered an important structure in hyolaryngeal dynamics.

Arthroscopically assisted anterior cruciate ligament reconstruction versus open reconstruction

One hundred patients have been included in this study, 54 of them had an open ACL reconstruction [group I] and 46 had an arthroscopically assisted reconstruction [group II]. Postoperatively, the open group had a traditional way of rehabilitation with a short period of immobilization and slow return to activity. While, the arthroscopic group had an accelerated way of early knee mobilization. The final evaluation was performed at the latest follow up which was 25 months in group I and 37 months in group II. The functional evaluation was evaluated using the Lysholm score. Excellent and good results were not noted in 88.9% in group I and 93.5% in group II, fair in 7.4% in group I an 2.2% in group II, proper in 3.7% in group I and 4.3% in group II

Funçäo dos ligamentos alares e transverso na estabilidade entre o atlas e o áxis: estudo experimental / Function of alar and transverse ligaments in the stability between the atlas and the axis: experimental study

Os autores estudaram em modelo experimental, em vertebras de cäes, a funçäo dos ligamentos alares e transverso na estabilidade entre o atlas e o áxis. Com base nos testes biomecânicos realizados, concluem que a resistência dos ligamentos alares e transverso säo equivalentes e proporcionais e que a ruptura do ligamento transverso só foi obtida nos ensaios em flexocompressäo, enquanto que a ruptura dos alares foi obtida em todos os mecanismos simulados