Ummm, the hand does not have any muscles in it (at least none that control finger movement). Hands have bone, ligaments, and tendons. The muscles that control movement of the fingers are located in the forearm. Tendons connect the muscles in your forearm to the bones in your hand and allow your fingers to move. Ligaments connect bones to other bones. The muscles that control finger movement along with the associated tendons and ligaments would have very little to do with your fingers getting broken (dislocated is another issue - at least where ligaments are concerned).
WildAikido, I've seen the injury that you mention. It seems to be caused more by a lack of proper technique rather than the type of punch used. Just as you said, if the angle is not right; fractured wrists or fingers can occur.
Just like everything else we do in life, practice leads to better technique.