To the best of my knowledge it is no different to a normal ultrasound, aside from the fact that they look more in depth for any anomalies
I think they look at all that well they look and make sure everything is there and looks ok if you mean a bio physical which looks at breathing and movement that's done more in the 3rd trimester if you are having some sort of issues
Ask your doctor if you haven't received your anatomy scan yet.
At 20 weeks I had a 2 hour scan of my baby's annatomy done by 3 doctors but I was also high risk so I'm not sure if that is typical...