Photoelastic and Finite Element Stress Analysis of the Gap between the L4 and L5 Vertebrae

The purpose of this study was to analyze the stresses on the intervertebral disc between vertebrae L4 and L5 when a compressive load is applied on vertebra L4 using the photoelasticity transmission technique and the finite element method. Nine photoelastic models were used and were divided into three groups. Each group was formed by three models, according to the localization of the sagittal cut on vertebrae L4-L5. Simulation was carried out using a load of 23 N. The fringe orders were assessed by points close to the edge of the intervertebral disc using the Tardy compensation method. The analyses using the photoelasticity technique and the model of the finite elements showed that the stress generated by the vertebrae on the intervertebral disc was higher in the posterolateral region. Thus, this region is more susceptible to pathologies such as hernia and disc degeneration.