Your unit has arrived on the scene of a multiple vehicle collision where several vehicles have rear-ended each other. You are directed by the incident commander to care for a 23-year-old female in the first vehicle. The firefighter on-scene holding manual spinal immobilization indicates that her primary complaint is back pain from her head whipping back and forth from the impact. Your understanding of the anatomy of the spinal column and vertebrae suggests that this type of mechanism of injury results in frequent injuries to which part of the spinal column?