Geometric Model for the Postural Characterization in the Sagital Plane of Lumbar Raquis

The individual’s posture is the physical expression of his body. It is modified throughout life and it is determined by the particular anatomical characteristics that directly affect the biomechanics of the spine. The typing of the spinal curvature is important for the knowledge of body posture. The possibility of having a method for the systematic postural characterization of the spine is an essential objective resource in order to obtain normal or control patterns of the spinal morphology of the population. A widely accepted methodology of morphological characterization of the spine is a necessary requirement for the establishment of preventive criteria for spinal pathologies based on epidemiological population studies. It also represents a necessary requirement for the classification of individuals, based on the biomechanical, orthopaedic or ergonomic criteria necessary for disciplines such as sports, industrial design or sports performance. The present study proposes the development of a morphological postural model of the spine in the lumbar region. The model is based on a system of measurement of objective and comparable parameters by means of X-ray analysis, in order to characterize its morphology in the sagittal plane. The comparison of the results in a population of 47 individuals allowed the possibility to carry out a statistical study on three morphological parameters: sacral angle (α1); reversal angle (α₂) and degree of lordosis (D_L). The statistical hypothesis that the results behave according to a normal distribution with p < 0.05 is relevant and allows the systematization and postural modelling of the individual.