Was that a foot?

So after a nice three-hour nap this afternoon, I was laying on my right side and felt significant movement from Baby S. I looked down and saw a small area bulging out just to the left of my belly button. Gasping and shrieking, I told mom, who I'd been chatting with on the phone. I'm still not sure which body part it was, but hopefully after this week's ultrasound we'll get a better idea whether or not it was a foot, hand, elbow, or knee, assuming the baby's position doesn't change too much within the next 48 hours.