When should an improvised sling be used?

An improvised sling should be used for upper limb fractures because it provides necessary support and stabilization to the injured arm, helping to minimize pain and prevent further injury. This is particularly important when the arm is fractured or dislocated, as immobilization is key to managing the injury until definitive medical care can be obtained.

In the context of treating injuries, using a sling effectively prevents unnecessary movement of the fractured limb. This not only aids in the healing process but also alleviates discomfort for the patient. In contrast, the other scenarios, such as managing head injuries, lower back injuries, or severe burns on the arms, require different approaches for stabilization and treatment, which do not involve the use of a sling.