The interesting question is who/what does the diagnosis. I've had my kids fall over a bunch of times (with a couple broken bones in there - never ambiguous, sadly) and broken a couple bones in my life too (as well as done stuff that convinced me that something must be broken in there, when nothing was).

So I think there were essentially zero times when a cheap-hand-held ultrasound in that home would have added information. The question is really whether this could be enormously helpful to a GP? Can they be trained usefully to take over some of the role of an ultrasound technician and do first-line diagnosis? It'd be great to not have to do the standard schlep over to the diagnosis place, wait around, get the thing done, and wait to get the results back to the GP or specialist.

I imagine there's also a fair bit of computer "vision" work on this stuff too - I would presume people are working feverishly away on ways of reconstructing 3D imagery and actual diagnoses of an image via computer, as opposed to squinting at these mysterious pictures.