Experimental scoliosis with the potential for marked progression was treated by rib resection on the concave side of the curve, and the alterations of the rib cage and vertebrae in the transverse plane were investigated. Twenty-four chickens were divided into four equal groups (groups R, P, PR, and C) and pinealectomy was performed at 3 days of age in groups P and PR. In group R, three unilateral ribs were resected at the age of 4 weeks. In group PR, three ribs on the concave side of scoliosis were resected at 4 weeks of age if scoliosis of > 20 degrees developed before the age of 4 weeks. Group C served as a control. Spinal radiographs and computed tomography scans at the apical vertebrae were taken at 20 weeks of age, and spinal deformities were evaluated. Scoliosis developed markedly in groups R and P, whereas it was mild in group PR. The apical vertebrae rotated to the convex side of the curve in all groups, in the same way as it would in human idiopathic scoliosis. In group PR, the Cobb angle and the rotation angle of the apical vertebra were symmetrically suppressed. This study indicated that rib resection might control the progression of scoliosis not only in the frontal plane but also in the axial plane when it was done on the concave side of the scoliosis. Although this experiment succeeded in chickens, application in humans is uncertain.