With the increasing number of prosthetic foot designs promising an ever widening spectrum of functions, the prosthetist is faced with new patient recommendation decisions. Although the basic families of feet still exist, such as Single Axis, SACH, Multi-Axis, Dynamic Response, new subsets are emerging that blur the lines between these accepted classifications. Also as foot designs incorporate new technology other terminology becomes necessary to differentiate the different classes of feet. New terminology will be presented that individually represents the component parts of current foot design Presentation will also compare physiologic foot function as presented by Perry, Radciffe, and others and outline the clinical factors that influence prosthetic foot recommendation.