How do I "anchor" a bone?

[Hans Rickheit]

Another basic question:

Here's a link to the file in question, if you need to look at it: https://www.dropbox.com/s/pzcyfsj1fvnde ... anime?dl=0

I'm sure this a very simple thing to do, but being a newbie, it eludes me. When I try moving the character's "stomach" bone, the entire body swivels, Her legs don't need o nova in this shot, so how do I "anchor" them so they'll stay firm in position?

[Hans Rickheit]

Never mind. It was just a bone parenting problem that I just didn't grok at first....