Using a sling to support an injured arm helps to immobilize the arm so that no further injury occurs. You can also use it to help prevent additional pain. Purchase a ready made sling from a retail store or use a triangular bandage, as found in many first aid kits. If neither option is available, simply cut a piece of fabric in a triangular shape to use as a sling. Follow these steps to wear the sling properly. Position the sling between the torso and the injured arm, with the largest angle resting near the elbow of the injured arm. If attempting to support the right arm in the sling, lay one end of the sling on the left shoulder. Take care to support the arm while positioning the other end of the sling upward and across the right shoulder. Grasp both ends of the sling, now on the shoulders and tie them behind the head. The arm should be resting parallel to the floor, in the sling. Put a bandage or cloth under the knot on the neck, so that the knot does not press uncomfortably on the neck. Grasp the angle at the elbow and twist. Tie a knot in the twisted material, so that the arm cannot slip out. Adjust the knot at the neck and/or the elbow allowing the arm to rest in the sling, in a position parallel to the floor. To keep the sling from swinging away from the body, tie a bandage around the sling and the body. The bandage should pass around the upper arm and the body. Source
