When caring for a suspected head, neck, or spinal injury in water, what is the proper method of manual in-line stabilization?

Using the head splint technique is the proper method of manual in-line stabilization for a suspected head, neck, or spinal injury in water. This technique involves using both hands to hold the victim's head in place, effectively preventing any movement of the neck and spine while keeping the head aligned with the body. By doing this, you are minimizing the risk of further injury during transport or when providing additional care.

While keeping the victim flat on their back is an important consideration in maintaining spinal alignment, it does not specifically address the need for stabilization of the head and neck in a water environment. Holding the victim's shoulders may not provide the necessary support for the head, which could lead to potential movement and exacerbate any existing injuries. Using a flotation device can help keep the victim afloat but does not serve the purpose of stabilizing the head and neck directly. The head splint technique is specifically designed to manage the situation safely while ensuring that the victim's spine remains in a neutral position, which is why it is considered the correct answer in this scenario.