The aim of this study was to compare the X-ray diagnosis with a non-invasive method for spine alignment assessment adopting a visual scan analysis with a plumb line and simetograph in middle-school students. The sample of this study was composed of 31 males and 50 females with an average age of 14.23 (± 3.11) years. The visual scan analysis was assessed at a school; whereas, the X-ray was performed in a hospital. The Wilcoxon signed-rank test was used to assess the differences between methods and scoliosis classifications (non-accentuated <10º and scoliosis >10º), and the Kappa was used to assess the agreement between methods. The comparisons between the methods revealed non-significant differences (z = −0.577; p = 0.564), with almost perfect agreement between tests (K = 0.821; p < 0.001). Moreover, no statistical significance was observed between methods by the scoliosis classification (z = −1.000; p = 0.317), with almost perfect agreement between tests (K = 0.888; p < 0.001). This research supports the conclusion that there are no significant differences between the two methods. Therefore, it should be highlighted that this field test should be used by physical education teachers in their classes, or in a school context, in order to determine misalignments or scoliosis prevalence among middle-school students. Int. J. Environ. Res. Public Health 2020, 17, x FOR PEER REVIEW 4 of 9 revealed an almost perfect agreement (K = 1.00, p < 0.001; please report to the statistical analysis 122 section) for both the alignment versus misalignment, and for the scoliosis degree visualization. 123 124 Figure 2. Left panel depicts the distance between evaluator and the instrument. The column's left 125 asymmetries are presented on the above right panel (equivalent for right misalignment) and bilateral 126 misalignment, at right below panel.127 2.3. X-ray method (clinical test) 128 After the visual scan assessment, the students were forwarded to a hospital for X-ray 129 analysis. They were evaluated by a spine surgeon in a standing position for long radiographies, 130 in the exact same position aforementioned, with the wood base for the foot position (Figure 3). 131 A specialist medical doctor carried out blind evaluations with column radiographies with a 132 Philips X-ray machine (Philips, System Medical -CYT9890, 010/87431 SN 14001512, 133 Amsterdam). The evaluation permitted the assessment of neck, shoulders, scapulae, thoracic, 134 and pelvic asymmetries.135 136 Figure 3. Philips X-ray machine with the wood base for the foot position.127 2.3. X-ray method (clinical test) 128 After the visual scan assessment, the students were forwarded to a hospital for X-ray 129 analysis. They were evaluated by a spine surgeon in a standing position for long radiographies, 130 in the exact same position aforementioned, with the wood base for the foot position (Figure 3). 131 A specialist medical doctor carried out blind evaluations with column radiographies with a 132 Philips X-ray machine (Philips, System Medical -CYT9890, 010/87431 SN 1400...