nub or no?! 🙊

I had an ultrasound at 13 weeks on Monday and got a few pictures of baby. As I was looking through them I noticed that I saw hands and feet up by the baby's head. I looked a little closer and I think I see a nub on the baby's crotch!? Idk 😶 this is baby #2 (I have a daughter) and in her ultrasound pics at 14 weeks I only ever saw 3 lines never a nub! Maybe I'm crazy but here's a pic, I'd love some opinions!! ☺️ I circled baby's hands and feet in red, possible nub in blue!