Method of determination of access areas from 3D patient images The invention relates to a method for automatically determining at least one pre-operative portal for arthroscopy from acquired pre-operative medical images of a bone of a patient, the method comprising the following steps: i) constructing a 3D surface(S) of the bone from the 3D image of the bone ii) determining anatomical landmarks of the bone from the 3D surface iii) determining a bone reference coordinate system (Rbone) iv) selecting at least one predetermined portal in a database of positions of predetermined portals v) determining a transform between the bone reference coordinate system (Rbone) and the model coordinate system (Ratlas) so that the bone of the patient and the bone of the reference person are matched in size, in position and/or shape vi) inferring from the transform and the at least one predetermined portal the pre-operative portal.
