Final answer:
A tourniquet is applied proximal to fracture sites in femur or humerus fractures to control bleeding and stabilize the fracture.
Step-by-step explanation:
Proximal long bone fractures, such as femur or humerus fractures, are commonly treated with a tourniquet. A tourniquet is applied proximal to the site of injury, meaning it is placed above the fracture site. This helps to control bleeding and stabilize the fracture during medical treatment. For example, if a patient has a femur fracture, a tourniquet may be applied above the thigh to temporarily stop the bleeding and immobilize the bone.