Point and Shoot, Macro, and Flash!

Hello,

I've been trying to select a digital camera and was wondering what
people would suggest.

My requirements:

1. Point'n'Shoot Size - I'm bringing it in to the hospital to take
pictures of cases, and can't carry a large camera (dSLR) with me all
the time (easy portability is valuable)
2. Swivel Screen - required so that I can hold the camera over the
operating table and take pictures from bird's eye
3. Macro - I take a lot of shots inside the mouth of objects maybe 1
cm in width, so I need something that has a decent macro function
4. Flash - I'd like it to be able to screw on a ring flash/light/LED
to help illuminate those macro shots
5. Price Point - $500 (or less!) for the camera would be nice ...

I've been looking at the Canon Powershot S1 IS, but have had trouble
finding an appropriate setup for the flash. Was also considering the
Nikon 5700 ...

Please let me know what you would suggest, and what experiences you've
had with that camera. Your help is appreciated!

Steve