It's bent but not locked, like what Arne and McDave say above, you'll just have to play with it. If you have a fixed vertical bar, like on a metal fence. Grab hold of it, lean on it. You'll notice if your using your muscle's it will get uncomfortable pretty quick. Now while your holding it straighten your arm out but don't lock it, now just slightly rotate your elbow so it's horizontal to the ground. What you should end up with is a slight bend in the elbow, but the pressure is really resting on the bone !
Good luck !