Spine configuration and range of motion in normals and scoliotics

The purposes of this study were twofold: to observe the effects of various seated postures on normal and scoliotic spines, and to investigate thoracolumbar range of motion in both normal and scoliotic spines. Eleven adolescent females with mild adolescent idiopathic scoliosis involving the thoracolumbar spine, and 20 healthy female subjects participated in the study. The Iowa Anatomical Position System was used to analyse the lumbar spine curvature. The five upright postures examined were standing, side-bending left, side-bending right, trunk extension, and trunk flexion. The seated postures consisted of erect sitting, slouched sitting, and each leg crossed two different ways in both erect and slouched positions. All seated postures were found to lie well within the extreme passive ranges of motion established by side-bending left, side-bending right, extension, and flexion. The thoracolumbar ranges of motion for scoliotics and normals were similar. Seated postures decreased the lumbar lordosis exhibited in standing for both scoliotics and normals. In general, the variety of seated postures had similar effects in normals and scoliotics, and individual seated postures varied little from each other in their effects on the thoracolumbar spine. All seated postures increased the lateral curvature in scoliotics.