[The intervertebral disk. Attempt at a "finite element" model].

Intervertebral disk composite model is unsatisfactory definite in biomechanical behaviour despite multiples technics used. Using histologic and histoenzymology it's possible to determinate proportions of collagen fibers in the different parts of the disk. A trustworthy finite element 3D model is proposed and tried by real experiments.

A model of the human lumbar vertebral column: a preliminary study.

Finite element modelling of the human lumbar vertebral column employs data-processing procedures for study of the linear and nonlinear elasticity of materials such as are currently used in mechanics or in civil engineering. Thanks to developments in computer science, requiring a close collaboration between doctors and engineers, we put forward in this preliminary study a linear computerised model of the lumbar column comprising 4824 meshes and 6813 nodes. By reducing the simplificatory hypotheses and integrating new parameters, this model as developed is capable of important clinical applications in surgery and ergonomics.

Preliminary study of the human lumbar spine using speckle technique. Limits of compression, shear and torsion. Speckle photography--electronic speckle pattern interferometry.

Optical techniques using single wavelength lasers allow precise study of the superficial displacements of deeper anatomical structures through direct mechanical pull. Two techniques have been used in this study: 1. Double exposure speckle photography.

Preliminary opto-electronic study on vertebral movement.

Opto-electronic systems utilising measurement of displacement of skin markers allows study of movement in the living subject. The authors have used this method in a kinematic study of the thoracic and lumbar spine measuring the displacement of skin markers placed over the spinous processes. It was possible to approach the physiological state of these complex movements once the apparatus had been calibrated to the correct level, and the error margins minimised.