Hypocycloidal polytomography is the most useful method for radiological examination of the integrity of the facial nerve. Minute changes in the bony wall of the facial canal are well visualized, and the exact site of injury to the facial nerve by cholesteatoma, foreign bodies, surgical injury, fractures, and tumors may be pinpointed. The wandering variations of the facial nerve in congenital anomalies can be assessed preoperatively with helpful accuracy.