I've been lucky enough never to have a broken leg, so I'm not sure if I'm describing it adequately. The character has just fallen in the woods.
"[FONT="]Pain shot up his leg, a sharp pain of torn muscles and then a numbness, perhaps a sign of broken bone."[/FONT]
I broke my leg riding a bike (my story posted now in MTS has a bit of what I recall).
Mine was actually "shattered" which is called comminuted. It was in dozens of pieces and there was a huge amount of soft tissue damage because it actually twisted around, so I don't think it would be the same sort of a broken bone that your character feels. I have actually heard of people who have broken the fibia, and sometimes it can be mistaken for a badly turned ankle.
The first thing is that there is no "real" pain for maybe a minute, not like you will eventually feel, anyway. You're basically on your butt, trying to figure out why you are on your butt. The sharp pain thing is not totally realistic. It goes numb first, pretty much, until your nerves assess the damage, and then you feel pain. Think "getting hit on the thumb by a hammer." You actually feel nothing at first, then your thumb feels sort of "dead" or "far away," then your thumb feels a thumping pain that goes up your arm. (Try this experiment. Go to the basement and get a hammer...) You immediately loose the ability to lift it in any way. There is no getting up and walking. The only exception is if the small fibula bone is the one that broke, then you can sort of walk, but not really. The pain is exactly like a very severe muscle cramp that will not end, like you might get in your calf, or the arch of your foot. If your leg moves, you can actually feel the razor sharp ends of the bones cutting and grating. The dull muscle cramp feeling throbs. Anytime anyone moves or touches it, the pain comes back. You cannot sleep without drugs unless you "pass out," or are exhausted. When it is in a position of rest, the pain subsides, so you beg the people who are helping you (if any) to leave you alone.
When you break your leg-- you know it. There is no "perhaps."
The sound is very loud, like a gunshot, or a truck backfiring. If you break both bones of the lower arm or leg, you hear double pops. I describe them as wet pops because it is like you would hear if you snapped a carrot in two, only much louder, maybe a little more brittle sounding. For more information go to mybrokenleg.com they have a really good explanation of the pain.
There are also stages to the pain. Within the first 24 hours, a massive amount of fluid goes to the leg in order for the osteoblasts osteoplasts to begin repair. It becomes hot, fever hot, because these cells need that heat to survive. The leg swells to nearly twice its size. They won't even cast it until this initial swelling has gone down. There is a "rush" of blood that you can actually hear in your ears when you sit up. It is like a river. The blood forms a cocoon around the broken part of the leg. This eventually becomes what is called the "soft callus." It is like a mass of blood clots. This becomes a hard callus as the injury site begins to rob calcium from all parts of your body to make raw building materials... There's more. It is quite interesting, but painful.
