Fig. 3From: New anatomical reference systems for the bones of the foot and ankle complex: definitions and exploitation on clinical conditionsDefinition of the calcaneus ARS: a) sphere fitted on anterior and middle talar facets; b) sphere fitted on posterior talar facet; c) x axis definition; d) plane fitted to the calcaneo-cuboidal articular surface; e) definition of the z axis; f) final ARSBack to article page