Width of the normal facial canal measured by high-resolution cone-beam computed tomography

Conclusions: In the facial canal, discrepancies between left and right side measurements at each point may be useful in the assessment and diagnosis of facial canal-related pathologies. Objectives: This study was performed to obtain accurate and high-resolution images of the normal facial canal and measure its widths on cross-sections of the canal at anatomically and clinically important sites using high-resolution cone-beam computed tomography (CBCT). Methods: CBCT volume data of bilateral temporal bones were obtained from 28 healthy adult volunteers. The widths of the bony facial canals were measured at the meatal foramen, the cochleariform process, the stapes, the pyramidal eminence, and the point of emergence of the chorda tympani in the vertical segment. Results: The widths of the facial canal at each point were similar bilaterally (r = 0.54–0.85, p < 0.01), but showed regional differences and site-specific variations. The narrowest of the five sites was the level of the meatal foramen (p < 0.05), as reported previously. The second narrowest site was the level of the stapes (p < 0.01) followed in order by the level of the cochleariform process, the pyramidal eminence, and the point of emergence of the chorda tympanis (p < 0.01).