In addition to all the good advice mentioned previously, depending on certain circumstances, you may want 1 or 3 PM&R rotations.
Say you rotated at your home institution which has an awesome, well-rounded PM&R department, then given the excellent exposure to the broad field of PM&R, which is about as broad as any field can get, as long as you got a great letter, and know a fair amount of PM&R knowledge by the end, then that one rotation maybe enough for you, and you can spend time doing other rotations that will help your Neuro and MSK knowledge & exam skills (ortho, rheum, neuro, rads, etc)
However, if your home institution lacks PM&R department or is not very well rounded (either overly outpatient or too much inpatient, usually the latter case), doing an away rotation or 2 in programs that will fill in the missing part of the exposure & education will help balance your application, and also help you to better determine what you eventually want to do in the future (and you will be asked about these things during interviews.)
IMO, in a well balanced program, you should be exposed to all of the following in some manner:
- Inpatient: traumatic and atraumatic brain injury, spinal cord injury, amputees, some disability
(generalized disability as the admitting diagnosis for the 99 out of 100 admissions is NOT well
rounded), Pediatric rehab (may also be outpatient)
- Outpatient: general acute/chronic MSK pathology (peripheral & axial joints), Sports (acute injuries),
Ultrasound-guided interventions, Fluoroscopic-guided interventions, EMGs.
- Others: Prosthetics & orthotics and cardiac rehab (not necessary as a student IMO)