Ultrasound hip scan hunnie, they use ultrasound to look at her hips and see if she has dislocated hips. It can be quite normal for a baby to have the scan these days, especially for those born a little earlier, etc, or congenital problems run in the family. Damien hasd the scan, it doesn't hurt then at all. It's is quite odd to see their pelvis on a scan! They are looking for bubbles in the joints I think? Not quite sure now, was a long time ago. My next baby will have one aswell. They are normally performed at 4-8 weeks old.
If dislocated hips are found, it is very easy to treat when they are that young. I had it as a kid and it wasn't diagnosed till i was 6 or 7 months when one of my legs was longer than the other. I ended up in a cast till I was 18 months. But that's pretty rare these days to happen. If they have the scan there is no need to worry that they will develop CDH (Congenital Dislocation of the Hips) later on.
Does that help? When is she to have it?