It's my understanding that, in general, women tend to be better able to express emotions than men. But I don't have any data to back that up.
I don't think that it is JUST the physical injuries but the circumstances as well. Falling down and breaking your arm would not have nearly as much emotional impact as having that arm deliberately broken by a loved one. I can certainly understand how those emotional injuries could be very deep and long-lasting.I also believe that, although physical injuries can also cause mental ones, they far more frequently don't. I have suffered many physical injuries, but I don't think any of them was accompanied by mental ones. Again, someone might like to dig up the facts and figures on this.