To elucidate whether the position of axis for rotation at the intervertebral
joint is related with the spinal curvature, the authors investigated the spinal columns of
beagles. The spinal column of beagle was composed of 7 cervical, 13 thoracic, 7 lumbar,
3 sacral, and 19 coccygeal vertebrae. It was observed that the position of axis for
rotation at the intervertebral joint was shifted on the superior and inferior views of the
2nd thoracic vertebra and was next shifted on the superior and inferior views of the 10th
thoracic vertebra. It was suggested that in the case of beagle and Wistar rat with 13
thoracic vertebrae, the upper shift of axial position for rotation at the intervertebral joint
occurred on the superior and inferior views of the 2nd thoracic vertebra and the lower
shift of axial position for rotation at the intervertebral joint occurred on the superior and
inferior views of the 10th thoracic vertebra
