the invention relates to a method for automatically determining , on a bone comprising a head portion contiguous to a neck portion , parameters for characterizing a bump deformation on the head - neck junction of the bone from acquired 3d medical image , the method comprising the following steps : i ) constructing a 3d surface model of the bone ; ii ) fitting a sphere on the spherical portion of the head of the bone ; iii ) determining a neck axis characterizing the neck portion of the bone ; iv ) determining from the fitted sphere and the neck axis , a clock face referential on the head of the bone rotating around the neck axis ; v ) determining a 3d curve on the 3d surface model characterizing the head - neck junction of the bone ; vi ) determining , from the 3d curve , the summit of the bump deformation of the head - neck junction of the bone ; vii ) determining , from said summit of the bump deformation , first and a second parameters characterizing the maximum bump deformation of the head - neck junction of the bone .