What is a key step to immobilizing a dislocated joint in first aid?

Using a splint to keep the joint from moving is essential for immobilizing a dislocated joint in first aid. This step is crucial because it helps prevent further injury to the surrounding tissues, ligaments, and nerves while also alleviating pain and promoting healing. Immobilization minimizes joint movement, which is necessary to avoid aggravating the dislocation or causing additional damage.

Applying heat is not appropriate in this scenario, as it can increase swelling and potentially worsen the injury. Encouraging movement is counterproductive as it could lead to further harm and discomfort. Although applying pressure may be relevant in some first aid situations to manage bleeding or swelling, it is not the primary or most effective step for immobilizing a dislocated joint. Thus, the use of a splint to stabilize the affected area is critical for proper care following a dislocation.