Is it normal that i think i have really strong bones?

While I was a kid, or younger teen, I did a lot of things that I feel would result in at least one broken bone, besides maybe a toe. But I have never had a broken bone. I've been in countless, literally countless bike wipeouts that leave me on the ground groaning in agony, but I always get up and realize I'm completely fine except for some soft tissue damage. I've been in countless sledding, snowboarding accidents too. Same old story.

I've sprained both knees, ankles, wrists. Each time I'm like, shit its probably broken, but it turns out its just a sprain. I've even hit my kneecap so hard that tissue separating the kneecap from the bones beneath it was completely crushed, but it did not result in a fracture of any kind. It did however form a cyst that eventually went away on its own.

I am a very skinny, bony person. My finger joints, elbows and knees don't really have that soft layer of fat over them, these areas of my body appear to be strait up skin and bone, which gives me a very fragile appearance. So I just don't understand why the ol'bones are so strong.