Introduction: The objective of this study was to investigate the morphologic characteristics between the vertebral body and the regions of the cervical and thoracic spinal cords where each rootlets branch out.
Methods: Sixteen adult cadavers (12 males and 4 females) with a mean age of 57.9 (range of 33 to 70 years old) were used in this study. The anatomical relationship between the exit points of the nerve roots from the posterior root entry zone at each spinal cord segment and their corresponding relevant vertebral bodies were also analyzed.
Results: Vertical span of the posterior root entry zone between the upper and lower rootlet originating from each spinal segment ranged from 10-12mm. The lengths of the rootlets from their point of origin at the spinal cord to their entrance into the intervertebral foramen were 5.9 mm at the third cervical nerve root and increased to 14.5 mm at the eighth cervical nerve root. At the lower segments of the nerve roots (T3 to T12), the posterior root entry zone of the relevant nerve roots had a corresponding anatomical relationship with the vertebral body that is two segments above. The posterior root entry zones of the sixth (94%) and seventh (81%) cervical nerve roots were located at a vertebral body a segment above from relevant segment.
Conclusions: Through these investigations, a more accurate diagnosis, the establishment of a better therapeutic plan, and a decrease in surgical complications can be expected when pathologic lesions occur in the spinal cord or vertebral body.
Patient Care: Because confusion over the anatomical structures can easily occur due to the limited surgical view associated with anterior cervical surgery, the measurement results taken from the subaxial cervical vertebrae in this study will contribute to a successful surgery.
Learning Objectives: Rootlets originating from the spinal cord that forms the spinal roots were arranged in single lines along the posterolateral furrow of the spinal cord. The more caudal cervical rootlets emerged from the spinal cord closer to the midline. This finding shows that pathological lesion in the central cord may cause
both myelopathy and radicular pain. Since the growth rate of the spinal nerve root and the vertebral body are different, the spinal cord segments between the third cervical nerve root and the first thoracic nerve root were located one vertebral body level above their corresponding relevant vertebral bodies.