Analysis of preexistent vertebral rotation in the normal spine.

Abstract

A newly developed CT measurement method was used to investigate axial rotation from T2 to L5 in the normal, nonscoliotic spine. To identify a preexistent rotational pattern in the normal, nonscoliotic spine. The data available on axial rotation measurements in the normal spine are scant and limited to only a few vertebrae. Systematic analysis of the thoracic and lumbar vertebrae of the normal spine, based on computed tomography has, to our knowledge, not been performed. CT scans of the thorax and abdomen of 50 persons without clinical or radiologic evidence of scoliosis were used to measure vertebral axial rotation from T2 to L5 with a newly developed semiautomatic computerized method. The results of the present study showed a predominant rotation to the left of the high thoracic vertebrae, and to the right of the mid and lower thoracic vertebrae in the normal, nonscoliotic spine, which differed significantly from an equal right-left distribution. This rotational pattern is present in both males and females. The normal, nonscoliotic spine demonstrates a preexistent pattern of vertebral rotation that corresponds to what is seen in the most prevalent types of thoracic idiopathic scoliosis.