Sometimes it is difficult to tell a cat has an injury as cats can hide pain very well. Some tell-tale signs could be being unable to jump, limping, possibly making a noise when the injured hip is...
My cat's tail was completely limp 4 weeks ago. I was told by many that it would probably have to be amputated. The cat was unhappy for the first week or two and did not like her tail being touched....
YOU TAKE THEM TO THE VET! If you think it may be broken, don't touch his/hers ribs or you migth hurt them , and definitely DON"T PICK THEM UP. You could make it worse.