A non-ionising approach based on 3D opto-electronic stereophotogrammetric measurements of body landmarks labelled by passive retro-reflective markers has been chosen to build a 3D parametric biomechanical skeleton model. The developed model can work at different stages of complexity. That is, depending on different analysis purposes and necessities, the parametric scaling can be detailed with several accurate anthropometric measurements, and the dimensions of each skeleton\u2019s component are estimated and fitted to match the subject\u2019s skeleton. To this aim, various protocols involving different body labelling (and so different related anthropometric data) have been established for separate analyses.A\u00a027 markers protocol has been set to analyse human posture and spinal associated pathologies (scoliosis, back pain etc.),\u00a0 and tested extensively in the clinical environment. With such a protocol some functional evaluation can be successively performed like Full 3D Multilevel Posturography\/Stabilometry and\/or Side Bendings to study spinal stiffness\/mobility.27 Markers set for Full Skeleton 3D Posture MeasurementThe following anatomical landmarks are identified:Anterior Aspect of Body: Markers (n=8)Left and Right Zygomatic bones,Mentum\u00a0(Chin at mental protuberance),Left and\u00a0Right Sterno-Clavicular Joint,Sternum at\u00a0Xyphoid prominence,Left and Right ASIS\u00a0(ASIS=Anterior Superior Iliac Spine)Posterior Aspect of Body: Markers (n=19)Spine Markers (n=11): from C7 down to S3 every second vertebra C7, T2, T4, T6, T8, T10, T12, L2, L4, S1, S3 (on the tip of spinous processes)Left and Right AcromionLeft and Right PSIS (PSIS=Posterior Superior Iliac Spine)Left Knee and Right Knee (back of the knee at the middle point\u00a0of the popliteal fossa)Left and Right Heel (lateral process of calcaneal tuberosity)When a more detailed description of lower limb segmental poses is sought, for instance when gait trials have to be considered, the used number of markers is to be increased.The\u00a0actual 27 Marker Protocol, chosen to build a 3D parametric biomechanical skeleton model, is part of a general methodology which can be applied indifferently to any stereo-photogrammetric recording system, provided that the latter is able to supply all the required landmarks three-dimensional coordinates, with known stereophotogrammetric error (after system calibration) in order to consider error\u00a0magnification during the processing\/elaboration chain.RecommendationHemispheric retro-reflective passive markers have to be adopted in order to minimise the bone-prominence\/marker distance and reduce geometrical interferences.The sizes of the adopted retro-reflective passive markers can vary depending\u00a0on the size of the subject that undergoes to examination.For subjects in the age range starting from adolescence through adulthood up to elderly the suggested marker size to adopt on the spine processes and on the Posterior Superior Iliac Spines (PSIS) of the pelvis is 10mm diameter. Conversely, 15mm diameter marker size can be used\u00a0to maximise the remaining body landmarks visibility during rotations.For children, the suggested marker size to adopt is smaller (down to 6mm)\u00a0depending\u00a0on the\u00a0size and\u00a0age of\u00a0the child under examination.Marker positioning has to be performed, by palpation, by a skilled, trained operator, with the subject in erect standing posture.