Evaluation of kinematic changes of intervertebral discs and the space available for the cord

Data on healthy human spinal cord morphometrics have been published for more than a century, using different measurement techniques and different anatomical landmarks. In recent years, there has been significant interest in the kinematic changes in disc bulging and the space available for the cord (SAC) in the cervical spine and the cauda equina in the lumbar spine (1-4). However, the kinematic changes in intervertebral discs and the SAC within the thoracic region have not been well analyzed and, as a result, the amount of movement of the thoracic spinal cord within the dural sac is still unknown.