Tail Wagging

Question
I hope you can help me with this, I have never seen such a thing and am wondering if you ever have:  We visited the home where we got our boxer puppy (she's 5 months old now) and the people kept one of the puppies from the litter.  The puppy only wags her tail up and down, it never goes back and forth!  Like I said, I have never seen such a thing and am wondering if you have any idea why it would do that?  

Answer
Hi, I have seen this before, and it can come from different things.  More than likely she broke something in her tail when she was born, (that is not that uncommon) or again from the birthing process (or docking if her tail is docked) she might have some nerve or ligament damage that is preventing her from wagging it correctly.  Most the time it is from something broken in the tail itself though.  Hope this helps,

Dawn