If you suspect your arm is broken, go to the hospital and do not attempt to create plaster casts at home. Even if you have access to medical casting supplies, a doctor must examine the arm and order X-rays to determine whether bones need to be realigned to heal correctly. To avoid additional strain on your hand, wrist, or elbow before getting to the hospital, you can use an inflatable air splint. Similar splinting supplies are available for infant and child arms.