What is the primary purpose of a splint in first aid?

The primary purpose of a splint in first aid is to immobilize the fracture. When a bone is broken, it is crucial to keep the affected area as still as possible to prevent further injury and to alleviate pain. Immobilization helps to stabilize the injury until professional medical assistance can be obtained. By securing the injured area with a splint, you limit the movement of the broken bone, which not only reduces the risk of further damage but also supports the healing process by keeping the bones in alignment.

While support for the injured area is also crucial, the specific emphasis on immobilization highlights its significance in managing fractures. Reducing swelling and providing warmth are important aspects of first aid but are secondary to the need to keep the fracture site stable and immobile. Maintaining the integrity of the fracture through immobilization is essential in the early stages of treatment, which underscores why this is the correct answer.