Which of the following is a common result of a whiplash injury?

Headaches are a common result of a whiplash injury due to the rapid back-and-forth motion of the neck that typically occurs during such an impact. This movement can cause strain on the muscles and ligaments in the cervical spine, leading to tension and pain that often manifests as headaches. These headaches can stem from a variety of sources, including muscle tightness, nerve irritation, and even changes in the cervical spine's alignment.

In contrast, lower back pain, wrist sprains, and knee instability are not typical direct results of whiplash, as these injuries primarily affect the neck and upper spine area. Lower back pain could arise from unrelated conditions or compensatory postures due to the injury, but it is not considered a primary symptom of whiplash. Similarly, wrist and knee injuries would generally result from different types of trauma or activities unrelated to the mechanism of a whiplash injury. Thus, headaches stand out as a prevalent and characteristic consequence of this type of neck injury.