Physical abuse at work...do I have recourse?

I work as a certified nurses' assitant at a nursing home in eastern Tennessee. I have worked there for 3 months. On my rounds, I must take care of an old gentleman who is very abusive, both physically and mentally. I have been pinched so hard that it leaves a black welt, I've been slapped, yelled at, bitten, and most recently, punched in the nose (which gave me a bloody nose). I have asked my supervisor and the home's director to be reassigned and have been turned down. I've begged for this man to be restrained, again, I was turned down.

I *need* this job! I dread going to work now. The administration doesn't seem to care about the well-being of their staff, only the paying residents get any respect. Should I consider this a normal part of the job? Do I have any legal recourse?