ASAP POSTURE v1
Authors: D'Amico Moreno , Kinel Edyta , Roncoletta Piero , D'Amico Gabriele 
Published: June 2018

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’s component are estimated and fitted to match the subject’s skeleton. To this aim, various protocols involving different body labelling (and so different related anthropometric data) have been established for separate analyses. A27 markers protocol has been set to analyse human posture and spinal associated pathologies (scoliosis, back pain etc.), 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 Measurement The following anatomical landmarks are identified: Anterior Aspect of Body: Markers (n=8) Left and Right Zygomatic bones, Mentum(Chin at mental protuberance), Left andRight Sterno-Clavicular Joint, Sternum atXyphoid prominence, Left and Right ASIS(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 Acromion Left and Right PSIS (PSIS=Posterior Superior Iliac Spine) Left Knee and Right Knee (back of the knee at the middle pointof 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. Theactual 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 errormagnification during the processing/elaboration chain. Recommendation Hemispheric 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 dependingon 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 usedto maximise the remaining body landmarks visibility during rotations. For children, the suggested marker size to adopt is smaller (down to 6mm)dependingon thesize andage ofthe child under examination. Marker positioning has to be performed, by palpation, by a skilled, trained operator, with the subject in erect standing posture.