Nub theory

Elisabeth • I'm a 25-year-old wife and momma to a 19-month-old little guy and expecting baby number two in April 2016!
I know all this guessing is just for fun but I still have over a month to wait before my sono! This is 11 weeks, 5 days, heart rate 174. Based on the nub theory, I would say boy...but I think that might be a leg instead? 
 ny guesses?