Place an ice pack
You need to place an ice pack over the area you suspect is broken. Continue applying ice pack until you get the medical assistance. It is advisable for you to keep it on the injured area for almost 20 to 30 minutes. However, you should refrain from putting ice directly on that area. You can wrap a clean towel around your arm before applying ice packs.
Make a sling out of your towel or shirt
You need to further immobilize your arm and can do this by making a sling out of a towel or a shirt, and tie it around your neck. You can even roll a thick paper around the arm and then tape it closely.
Get medical assistance immediately
Seek medical assistance as soon as possible. Keep in mind that X-rays will let you know about the type of the fracture and what treatment you require. The doctors will also decide on the type of immobilization you require. You can have a splint or partial cast if you have a fracture in radius or ulna. For fractures in upper arm and shoulder, splints are applicable.
Apply ice packs to treat swelling
After you come back home, you need to continue applying ice packs in order to treat the swelling. You should also consume medication which your doctor has prescribed.