Anatomy of the facial nerve [F N] within the parotid gland

ABSTRACT

Facial nerve [FN] paralysis is the most serious and frequently encountered complication of parotid surgery. Review of literature revealed that preoperative and intraoperative FN identification by radiological methods, FN monitoring and FN stimulating test failed in completely solving this problem. The present study aimed to detail the intraparotid anatomy of FN 25 cadaveric head sides with intact skin were dissected to identify the parotid gland and its surrounding structures. Then the parotid tissue superficial to FN and its branches was removed. The FN bifurcated 2.1-5 mm behind the retromandibular vein [RMV] into upper and lower divisions. Both divisions passed superficial to RMV in 22 cases, the upper division passed deep in 2 cases and the lower division passed deep in one case. The FN divisions or their branches were in close contact with RMV except in one case where the upper division was separated from the vein by a small amount of parotid tissue. The site of branching of the upper and lower divisions was variable and occurred either behind RMV, at the point of crossing of the vein or infront of it. The mean lengths of FN trunk, upper division and lower division were 17.6, 5.4 and 8.9 mm respectively. Communications between FN branches were observed both within and outside the gland. These results may be helpful for radiologists and surgeons dealing with the parotid region