The invention relates to an automated method for precise determination of the head center and radius and the neck axis of an articulated bone from acquired 3D medical image of an articulation, comprising the following steps: i) determining, from a 3D image of the bone, an approximate sphere (SFO) of the head of the bone that substantially fits the spherical portion of the head of the bone； ii) constructing from the 3D image and the approximate sphere (SFO), a 3D surface model (S) of the bone； iii) determining, from the 3D surface model (S) and from the approximate sphere (SFO), an approximate neck axis (AXO) of the neck of the bone； iv) determining, from the 3D surface model (S) and the approximate sphere (SFO), a precise sphere (SF)； v) determining, from the 3D surface model (S), the precise sphere (SF) and the approximate neck axis (AXO), a precise neck axis (AX1).
