CSA of the psoas major adjusted by mean height was 546.2mm2 (296~769.3), and that of the lumbar extensor was 1389.9mm2 (913.6~2518.4). The mean radiographic parameters showed as follows; C7 plum line: 5.47mm, major Cobb angle: 40.0º, SVA: 93.0mm, upper thoracic kyphosis (T2-5): 8.1º, thoracic kyphosis (T5-12): 13.9º, thoracolumbar kyphosis (T10-L2): 10.6º, lumbar lordosis (L1-S1): -8.5º, pelvic incidence: 53.2º, pelvic tilt: 36.6º, and sacral slope: 16.6º. The CSA of psoas major was correlated with thoracolumbar kyohosis (rs=0.562, p<0.01), and pelvic tilt (rs=-0.481, p<0.05). The CSA of lumbar extensor was correlated with lumbar lordosis (rs=-0.533, p<0.05), and pelvic tilt (rs=-0.433, p<0.05). The CSAs of trunk muscles demonstrated no correlations with age, and body mass index.