Heh, I *always* have bruises and scrapes on my legs and elbows! I don't even need to fall to get them. I just bonk myself on my bike because I'm klutzy sometimes. (Mountain biking is not the ideal sport for a klutz! ) I also get "chain ring tattoos" on my calves (those sting & bleed a surprising amount). However, that being said, I recently got some elbow guards and shin/knee guards and that has helped a lot... though I still get bruised on my calves where the guard doesn't protect! LOL! The protective gear was a necessity simply because a) I was going to Mammoth and they were a must riding the trails there and b) people at my job were kind of horrified by seeing big scabs & bruises on my elbows.

I've endo'd, tipped over, scraped myself riding too close to boulders or foliage... you name it. What I've learned, though, is that even the most advanced bikers fall, so it's not necessarily skill. Somtimes it just happens. I know I fall a lot recently simply because I'm challenging myself more and taking more risks. My own personal philosophy is that in order to improve I need to challenge myself. I've also noticed that a lot of the worst falls tend to happen when you're fatigued.

You might want to look into getting some protective gear for the places you seem to injure the most.