Final answer:
A tourniquet should be applied to the upper arm, specifically at about the level of the heart when properly used in medical situations.
Step-by-step explanation:
A tourniquet should be applied to the upper arm, specifically at about the level of the heart when properly used in medical situations. The purpose of a tourniquet is to temporarily cut off blood flow to a particular area of the body. By placing the tourniquet higher up on the arm, it can effectively stop blood flow to the lower part of the arm or hand.