Analysis of Anterior Trunk Symmetry Index (ATSI) in healthy school children based on 2D digital photography: normal limits for age 7-10 years

Background Digital photography for a 2-dimensional assessment of the body shape is a valuable method to both document the human posture and calculate the main quantitative parameters of it. Purpose The goal of this study was to assess the frontal plane symmetry of the anterior trunk in healthy school children based on the digital photography by measurement of the Anterior Trunk Symmetry Index (ATSI). . Methods The study comprised 421 school children, both sexes, aged 7-10 years, with no clinical evidence of scoliosis (Angle of Trunk Rotation <5o). One frontal photograph of anterior trunk in spontaneous standing position was taken with a digital camera in standardized manner. The semi-automatic software for calculation of photogrammetric parameters was developed in collaboration with an IT specialist. The photographs were analyzed to obtain a quantitative assessment of the ATSI parameter. The intra-observer error was calculated by the first author by measuring the pictures of 14 children three times, selected randomly, at the interval of at least two days. The inter-observer error was calculated by one surgeon and two experienced physiotherapists by measuring the pictures of 60 children, selected randomly. The normal upper value limit was calculated as mean + 2SD. Results