Studies of lumbar intradiscal pressure (IDP) in standing and upright sitting have mostly reported higher pressures in sitting. It was assumed clinically that flexion of the lumbar spine in sitting relative to standing, caused higher IDP, disc degeneration or rupture, and low back pain. IDP indicates axial compressive load upon a non-degenerate disc, but provides little or no indication of shear...

This study explores the inertial effects of the head and torso on cervical spine dynamics with the specific goal of determining whether the head mass can provide a constraining cervical spine end condition. The hypothesis was tested using a low friction impact surface and a pocketing foam impact surface. Impact orientation was also varied. Tests were conducted on whole unembalmed heads and cerv...

PURPOSE In a meta-analysis of the literature we evaluated the present knowledge of the material properties of cortical and cancellous bone to answer the question whether the available data are sufficient to realize anisotropic finite element (FE)-models of the proximal femur. MATERIAL AND METHOD All studies that met the following criteria were analyzed: Young's modulus, tensile, compressive a...

Tissue-engineered musculoskeletal soft tissues typically lack the appropriate mechanical robustness of their native counterparts, hindering their clinical applicability. With structure and function being intimately linked, efforts to capture the anatomical shape and matrix organization of native tissues are imperative to engineer functionally robust and anisotropic tissues capable of withstandi...

geometric and material nonlinear behavior of slender webs in i-column girders having stocky flanges under the action of combined lateral and axial loads is investigated. interaction curves corresponding to the application of compressive and shear loads at buckling and ultimate stages for both web plates and column sections are plotted. in addition, the effects of flange and web slenderness rati...

In previous work (Peters and Poort, 1983), the stress distribution in axisymmetric models of restored teeth was analyzed by finite element analysis (FEA). To compare the tri-axial stress state at different sites, they calculated the Von Mises equivalent stress and used it as an indication for weak sites. However, the use of Von Mises' theory for material failure requires that the compressive an...

INTRODUCTION: Intervertebral disc experiences large complex deformations including compression, rotation, and bending under daily activity. For example, twisting while carrying a weight, loads the disc under axial compression and axial rotation. Previous work showed that the rate of degeneration and disc injury is higher for in workers that experience repetitive twisting and lifting [1]. Disc d...

STUDY DESIGN Biomechanics of human intervertebral discs before and after nucleotomy. OBJECTIVE To noninvasively quantify the effect of nucleotomy on internal strains under axial compression in flexion, neutral, and extension positions, and to determine whether the change in strains depended on degeneration. SUMMARY OF BACKGROUND DATA Herniation and nucleotomy may accelerate the progression ...