Prevalence study of trunk asymmetries and structural scoliosis in 10-year-old school children.

The prevalence of trunk asymmetries was studied in 6464, 10-year-old, school children in Malmö City. All those with visible trunk asymmetries were moiré photographed and a subset roentgenographed. Moiré, positive findings were seen in 13% of the boys and in 16% of the girls. A more prominent moiré asymmetry (a deviation of two moire contour lines or more) was seen in 0.6% of the boys and 0.9% of the girls. The Cobb angles in this latter group varied between 14-25 degrees. Children with small clinical and moiré asymmetries (deviations of less than one moiré fringe) had no or very small (less than 10 degrees), lateral deviations seen on the x-ray and should, therefore, be regarded rather as normal variations of the shape of the trunk. On the other hand, these small asymmetries cannot be disregarded as possible indications of a risk group in which structural scoliosis can develop later during the period of growth.