What is the primary purpose of using a tourniquet for an injured limb?

The primary purpose of using a tourniquet is to stop severe bleeding. When an injury causes a significant loss of blood, especially from a limb, a tourniquet can be applied to compress the blood vessels and control the hemorrhage. This is critical in situations where direct pressure may not be effective or feasible, such as with arterial bleeding. The application of a tourniquet can help to stabilize the patient's condition and prevent shock, allowing for more effective treatment and transportation to medical care.

While immobilization, reducing swelling, and providing support are all important aspects of first aid and injury management, they are not the primary function of a tourniquet. The focus of a tourniquet is solely on controlling life-threatening bleeding, making it a vital tool in emergency situations.