This site displays Radlex 2.1, an older version, but one that is in a better format for browsing (with anatomy organized mostly by PART relation). Go here for Radlex 3.0: http://bioportal.bioontology.org/ontologies/40885 , a newer version organized mostly by IS_A relations, and with greatly enhanced neuro terminology, recommended for applications. Read about the latest updates to RadLex: http://www.rsna.org/radlex