Broken bones suck. There is no way around that. They are a gigantic inconvenience, especially in a life or death survival situation, and they hurt like hell.
An important thing to note, before going further, is that there are two types of broken bones (we know right? as if one wasn't enough). There are what are known as open, and closed fractures. This is going to sound really gross, but open fractures are "compound" fractures that involve the bone breaking through the skin. A good example of this can be found when Jeff Goldblum totally screwed up that lumberjack's arm in The Fly. The closed fracture, on the otherhand, is not nearly as gory and saves you a step in the healing process.
One of the most important things to remember with any fracture is that it needs to be immobilized. Other than the fact that it will be throbbing with pain if you poke it or try to walk on it, the smart reason to do this is because without splints, fractures can either sever or compress vital nerve endings or blood vessels in your body. You don't want either of these things happening, trust us on this one.
Splint prep for an extremity such as a finger, arm, or leg will consist of two pieces of sturdy material as well as a binding agent. That is a fancy way of saying two sticks and your t-shirt if you are stuck out in the woods, just an FYI.
There are two steps you will need to take and/or maintain before setting your splint. The first is setting the bone. You aren't going to like it, and it won't feel good, but unless you want a really weird looking finger, arm, leg or whatever post-healing, you will want to do this. Setting just means putting the pieces back where they belong, usually through loud cursing and lots of pulling. The second thing you will need to maintain with the help of your splint is what is called traction. Traction is holding the bone where it needs to be so it can heal properly.
Fingers and arms are a bit "easier" since you will still be able to walk, so we'll just quickly run you through how to take care of a leg instead.
- Find two branches with forked ends that are about the size of a large shotgun shell in diameter. One of them needs to run from your armpit all the way down your side and past the point of the break. See the picture at the top right for a visual. In that instance it needed to go past the foot.
- Reinforce the splints with padding, this could be a shirt or even leaves if you are in a real pinch. Notch the un-forked end and attach a crossbar the same thickness as your branches on the end.
- With a ripped t-shirt, vines, rope etc., attached the two splints to the outside of the body and the inside of the leg, as illustrated in the picture above. Also attached a strap running around the ankle to the crossbar.
- This part is really going to suck, but is totally needed so here it goes.... Take a stick and slide it in between the strap holding your ankle to the crossbar and start twisting until the broken leg is as long, or even slightly (SLIGHTLY) longer than the unbroken leg. We know this sounds very Saw IIIish, but the bone will not heal properly without this technique.
- Lash the stick you twisted to the main traction and feel free to pass out for a bit. You could probably use the nap at this point.