The power of google:
http://www.nrhrehab.org/Patient+Care/Conditions/default.aspx
but in short probably sci injury, neuro-rehab/stroke/tbi, amputees/ortho are large constituencies.
Also saw some cancer rehab and burns.
Emergencies:
I think the key for this is realizing when someone is "sick." "Sick" people need to go to the acute medicine floor via transfer (if your unit is attached like say at UW) or via ambulance (if you are at a free standing hospital like RIC). "Smelling" when someone is sick is what intern year is for, I suppose - your 95 year old woman with pneumosepsis, for example.