Bony landmarks as an aid for intraoperative facial nerve identification.

Identification of the facial nerve trunk is essential during surgery of the parotid gland. Numerous landmarks have been researched and used. The relation between the facial nerve to two constant bony landmarks, the tip of the mastoid process and the central point of the transverse process of the atlas was investigated. Forty cadavers were dissected. A preauricular incision exposed the nerve trunk. Bony landmarks were identified and marked. The distance from the nerve trunk to the mastoid process and the atlas was measured. The mean distance between the mastoid process and nerve for the left was 9.18 +/- 2.05 mm and for the right, 9.35 +/- 1.67 mm. The mean distance between the atlas and the nerve for the left was 14.31 +/- 3.59 mm and for the right, 13.76 +/- 4.65 mm. Confidence intervals were determined. The importance of the aforementioned data revolves around minimizing the chance of injury to the facial nerve during surgery. The applicability of these landmarks needs to be studied in the clinical setting.