One of the characteristics of having O.I. is bone deformity or 'bowing' of the bone. Arms and legs may look like boomerangs but instead of rebounding back to the thrower, some can cause pain to the owner and others have many microscopic cracks in the bone due to the bowing. I'm not sure of the exact science behind the cause of the bowing, but I know that the inadequate state of collagen (a protein in the body that creates the scaffolding for bones) is one of the primary culprits of the deformities.

But all of that stuff you could have looked up on Google or asked your doctor about. As someone with many bowed bones - some which have been surgically straightened with a pin or a rod, and others just left alone, I can tell you that they are (for me) a source of embarrassment and annoyance. Take for instance my right arm:

My right arm hangs at a downwards right angle at my side. The elbow juts outwards away from my body, and then the rest of my arm just dangles down - I have never remembered my elbow to be able to completely straighten itself. This was always a problem when I had to have blood tests - even though I am a lefty my blood is never drawn from my unused right hand. It is never able to lay flat on the arm rest for the blood drawer to stick the needle in. Instead my right arm awkwardly lays on its side, pinky finger against the flat surface tilted towards me. If you've ever played the game "7-up thumbs up, heads down" in school my right hand is perpetually ready to play that game all the time. So after struggling to get it to go straighter I'll look up at pathetically at the phlebotomist as they ask:
"Is that as straight as your arm will go?"
"...Yeah"
"Alright, I guess you were right - let's just use your left hand then."

But there are some things that my right hand is good for. It's angled perfectly to rest my head in the palm of my right hand when I am tired, and it is able to reach outwards just enough to grab open a door as my left hand steers my wheelchair through. When I raise my right hand in class or to get anyone's attention it accomplishes the task quickly because of its awkwardness, teachers are never sure if my dangling arced arm is stretching or if I am actually raising my hand.
Sometimes people will ask me if my right arm hurts me and it never does. Or maybe it does and I just don't know any different since it's been this way for as long as I can remember. When I was younger I hated my right arm and would use my other arm to try and pull it straight, or bang my left fist against my right elbow to try and unlock the joint. Of course it was always to no avail but I tried! My parents always looked horrified when I did this and always hollered at me to quit doing that.

Though I don't know many O.I.'ers and I've never talked to any of the O.I.'ers that I know about this, I am sure that (like anyone else) every O.I. has a part of their body that they wish would function or look better. I don't mean that we wish our bodies would look un-affected by O.I., I mean to say that in comparison to the rest of our bodies there is always something that does not 'work' as well as the rest of our quirky anatomy.

Bowed Bones:

•  When I was much younger I never understood why my bones were bowed. In my mind just because they were brittle that didn't mean they should be curved as well! Helping young kids understand where their deformities come from or how they happened (from an old fracture that didn't heal well, or from poor collagen, or other reasons) will help them better understand their bodies as they get older
• Adjusting clothes to better fit bowed bones may be necessary. For instance super tight jeans over a bowed tibia may not be the best idea
• This is something I am still working on, but learning how to accept the body and not be embarrassed about bone deformities will take a great deal of time - especially if some bowing may get worse (or better) over time and medical treatments
• I have found that working with physical therapists or occupational therapists to help fully utilize a bowed limb has always been beneficial and safe
• If legs become progressively bowed and the individual wears braces, it's helpful to modify the braces according to the bowing. I used to experience painful pressure points from where brace coverings would press to a bowed part in my tibia because the brace was not adjusted accordingly
• Even if the pain in a bowing site is not one akin to the pain of a fracture, if there ever is pain I suggest it be checked out by a doctor - this might mean the limb is becoming further bowed and options should be discussed