Fig. 6 Z-shaped course of right facial nerve, anterolateral view. CPA, cerebellopontine angle segment; IAC, internal auditory canal segment; Tymp., tympanic segment in middle ear; Mast., mastoid segment; SMF, stylomastoid foramen. Segment lengths as indicated. (Adapted from Guerrier Y: Surgical anatomy, particularly vascular supply of the facial nerve. In Fisch U (ed): Facial Nerve Surgery. Birmingham, AL: Aesculapius, 1977:12–23)