just noticed the nub!

Omg as I was looking closer at this pic from my 12 week scan I think I noticed a nub?? It's a lot brighter white, kind of on the end of the baby's body (not the white line above). Is this possibly the nub or do you think it was just another body part or something to do with the amniotic fluid ? Because I don't really see another leg so this is confusing.