Visualizing the hierarchy of your search

I think this is pretty good try by the folks at the Gale Health Reference Center to provide a visualization to assist in the search process (Give it a try beginning at our 24/7 database page).

My search for "sports concussions" generates this this nifty pie-like graphic that breaks down my search term into two levels of sub-categories; nicely showing that connecting relationship. Selecting either the inner or outer ring yields the corresponding articles to the right.