I don't want to rewrite all that is out there about safety...I'm being lazy but I'm behind on topics and yeah... Here are great sources for horse safety information. Below are a couple diagrams that I think are either funny (1st photo) or interesting (2nd one) or sell certain safety messages (3rd picture).
Lastly, wear a helmet when ever you are riding so your head doesn't have this happen to it! Better to have a $50 helmet take the brunt of a bad fall!!! Stay safe!