how do we know that we have a healthy bone...?

Answer 1

You could have a bone density test done, but it is very painful. Just make sure you do some kind of loading bearing weight on most important bones. Like weight lifting, legs, arms chest etc... This helps to keep bones healthy and strong. Drink milk which is loaded with Vit D which helps also to promote strong bones. If you have never had a broken bone yet, chanes are you have good healthy bones.

Answer 2

If you are able to carry out your activities of daily living without any problems, that is the simplest gauge as to whether your bones are healthy nor not.