Which of the following is a crucial step in performing the head tilt-chin lift maneuver?

The head tilt-chin lift maneuver is a primary technique used to open the airway in patients who are unresponsive and not breathing normally. The method involves using one hand to tilt the patient's head back by placing fingers on the forehead while the other hand is positioned under the jaw to lift it forward. This action moves the tongue away from the back of the throat, reducing the risk of airway obstruction caused by the tongue falling backward.

By utilizing the designated hand placements, the rescuer can effectively create a clear path for air to enter the lungs, thereby facilitating rescue breathing if necessary. This technique is crucial because it helps maintain oxygen supply to the brain and other vital organs until further help arrives.

In contrast, other suggested actions such as pressing deeply into the soft tissue under the chin or completely closing the mouth do not effectively address the need to maintain an open airway and can actually impede effective ventilation. Placing hands on the chest does not contribute to achieving the goal of the maneuver, which is to clear the airway. Thus, the correct execution and understanding of the head tilt-chin lift approach is essential for anyone performing basic life support.