1. A method of measuring geometric variables of a three-dimensional structure contained in an object from at least one image (I j ) representing the object, comprising the following steps: use of a deformable first model (M) describing the structure, the shape of which model can be described by parameters (b), adjustment of the first model to the structure in the image (I j ), determination of the parameters (b j ,) at which the first model exhibits optimum conformity with the structure, use of a deformable second model (M*) describing the structure, which second model in shape corresponds to the first model, and which in addition contains at least one geometric variable, modification of the second model according to the parameters determined, and derivation of the geometric variable(s) from the modified second model.