In many ancient medical practices they advocate someone eat the part of the animal that they are having problems with. In your case I guess that would mean you should eat bones according to that POV. Better get chomping.

There are things you can do to ensure you are at optimal health (diet, exercise), but you would do best to learn to accept your body shape, which almost certainly is genetic. I am also small-framed, at 19 years old I was 119 lbs at 5'11". Body image is a struggle, I always want to be more Schwarzenegger than olive oyl. I went through a skinny-fat phase about 170 lbs. I am now ~155 lbs, which seems to be the weight my body WANTS to be. So I accept this and now I'm focused on becoming an efficient fat burner, and achieving optimal health.

All that said, maybe you could join crossfit and up your calories, if you really want to see if you can fill out a bit more. Just don't try to get too tied up in what you WISH you looked like.

I've been thinking about the same thing. I'm 5'6 and skinny. My arms look like a girls! MY forearms are particularly small and my wrists are tiny. I've been doing paleo and strength training to try to fill out but I have a couple of additional problems in that I am currently in China and food quality and diversity is poor, and I think I have some kind of auto-immune condition, at least I definitely have a leaky gut, that I have been close to curing but then coming to China has messed up again.

I did recently start thinking maybe the best thing is to accept my body as it is and focus on increasing strength and fitness and not worry about size. I also wonder if with a small bone frame does that mean you can only add so much muscle mass? I seem to be getting strains in my elbow from the strength work, which is bodyweights btw, could that be due to my small frame?

When I think about accepting body image I try to think about Bruce Lee, a small but very powerful guy. I don't think anyone would have a problem having his physique.