Which method is commonly used to check a casualty's response to pain?

The sternum rub is a widely accepted method for checking a casualty's response to pain, particularly in emergency medical situations. This technique involves applying pressure with a knuckle or similar object to the sternum, which can elicit a reflexive reaction from the individual if they are conscious or semi-conscious. The intensity of the pressure can help assess the level of consciousness and responsiveness, indicating whether the casualty may require further medical attention.

In practice, responders often use this method because it is quick, effective, and can provide immediate feedback about the casualty’s awareness and responsiveness. Since pain response is a critical component in evaluating a casualty's condition, the sternum rub serves as a reliable indicator in triaging and managing a potential medical emergency.