The anatomical relationship of the parotid duct to the buccal and zygomatic branches of the facial nerve: a Sri Lankan cadaveric study

Abstract

INTRODUCTION & OBJECTIVES: The aim of this study was to demonstrate the anatomical relationship of the parotid duct to the buccal and zygomatic branches of the facial nerve and provide information to preserve these structures in parotid surgeries. METHODS: Fifteen cadavers (20 parotid areas) were dissected at the Anatomy Department, Faculty of Medicine, University of Kelaniya to demonstrate the pathway of the parotid duct and course of the buccal and zygomatic branches of the facial nerve. Twelve Anatomical parameters were measured by a flexible tape. RESULTS: Of 20 specimens, two (10%) had two buccal branches, two (10%) had two zygomatic branches, one had an accessory parotid gland, one had an accessory parotid duct. Mean parotid duct length was 34.88mm (SD-6.31, CV-18.09). Mean distance between the beginning of the parotid duct and the point at which the zygomatic nerve crossed the duct was 19.36mm (SD-6.82, CV-35.19%). The average distance between the lateral canthus and intersection point of the zygomatic nerve and duct was 52.45mm (SD-3.15, CV-6.05%). Mean distance between the zygomatic arch and the above intersection point was 20.73mm (SD-2.49, CV-12.01%). CONCLUSION: The reliable measurement in our study with the smallest coefficient variation was the distance between the lateral canthus and intersection point of the zygomatic nerve and parotid duct; 52.45mm. Thus the intersection point of the zygomatic nerve and duct lies between 46.15 - 58.75mm from the lateral canthus. If two circles are drawn with radii of 46.15mm and 58.75mm from the lateral canthus the duct will mark a segment along its pathway, within which 95% confidence the intersection point with the zygomatic branch will lie.