"...What the hell is a Medical Geographer?..."

That is easy.

Every time you see an article that has a headline like "where you live has an effect on if you have a tonsillectomy", or "Where you live correlates to longevity" someone does the work, and creates the maps for this. Take a Geospatial Information Systems course (GIS - a hot area of study), and you will see.

But you knew this, right?