The facial nerve canal: CT analysis of the protruding tympanic segment.

The development and subsequent course of the facial nerve canal are complex. High resolution computed tomography (HRCT) provides an opportunity for the study of this often perplexing structure. Normal anatomy and normal variations of the facial nerve canal must be considered when examining patients who have facial nerve palsy referrable to the temporal bone. The author recommends direct axial and coronal imaging supplemented by sagittal and possibly oblique reformations.