Under which circumstances should a c-collar and in-line movement to the cot be applied without a backboard?

The application of a cervical collar and in-line stabilization to the cot without the use of a backboard is warranted particularly in situations where there is a high risk mechanism of injury. This is because a high-risk mechanism, such as a significant motor vehicle accident, a fall from a considerable height, or any situation where there is concern for potential spinal injury, necessitates immediate precautions. Stabilization is essential to prevent any movement that could exacerbate a potential spinal injury.

Utilizing a c-collar and maintaining in-line stabilization helps protect the spine and ensure that the patient's head and neck remain in a neutral position during transport. In scenarios where there is a suspected spinal injury due to the nature of the incident, but other indicators may not dictate the use of a backboard, this method remains effective in safeguarding the patient from further harm.

The other circumstances presented, such as the absence of pain on neck motion, full consciousness and alertness, or the presence of only confusion, indicate a lower likelihood of significant spinal injury and might not require such strict stabilization measures. It's crucial to assess the mechanism of injury first, as this directs the need for spinal precautions.