Exposing the facial nerve is one of the most delicate tasks in mastoidectomy. In this step, the bone is removed until facial nerve and chorda tympani become visible, leaving only a thin layer of bone over the nerves.
The left image shows the surgical site in the Voxel-Man Tempo surgery simulator, after this step has been performed on a left ear. The short process of the incus is also clearly visible.
The right image shows exactly the same view, but without the bone. It contains all the structures at risk in the virtual 3D anatomy model of the temporal bone such as sigmoid sinus, facial nerve, chorda tympani, tympanic membrane, auditory ossicles, cochlea, semicircular canals and dura.