I usually keep a few Michael Turner and J. Scott Campbell images handy. No, you don't need to know anatomy. If you can make a woman look dynamic and make her look hot, you can get away with anything.
Need proof? Here is the "subject to change" cover of DC's Catwoman #0:
I have stared at this for two minutes now, and I cannot see how in the hell anyone is supposed to bend like that.
Sheesh, I admit my drawing of Supergirl was bad, but I'd rather have my bad style than "used as currency in men's correctional facilities" style. In case you're wondering why I'm sticking with my cartoony style....