Training in microsurgery of the middle ear requires dissecting to be carried out on petrous bone. Human petrous bone structures are not available in adequate quantity to permit extensive practicing. Using synthetic resins, true reproductions of petrous bone can be obtained by means of a stereolithographic method, yielding structures of the petrous part which are highly similar to human bone. Digital data sets are obtained from spiral CT scans, and transferred to CAD systems such that, using stereolithography, petrous bone facsimiles are produced on the parametric model. Any number of such models of an original can be produced. Thus, identical structures can be made available for a wide range of uses. Exercises conducted on artificial petrous bone so produced are equivalent to those carried out on human structures, in terms of material properties and visualisation of anatomic details.