An Anatomical Study of Extratemporal Ramification of Facial Nerve in the Patey’s Plane of Parotid Gland and its Relation to Retromandibular Vein

Abstract

Introduction: Expression is an art. Our facial expressions are brought out by the subcutaneously placed facial muscles. They are supplied by the facial nerve. Preservation of the facial nerve during rhytidectomy, parotidectomy and other cosmetic and therapeutical surgeries makes the study of facial nerve anatomy compulsory. Aim: To emphasise on the anatomy of facial nerve and its branches and its relation to retromandibular vein in the Patey's plane of Parotid gland. Materials and Methods: This was a cross-sectional observational study, conducted for a period of two years from September 2013 to August 2015 in the Department of Anatomy of Karpaga Vinayaga Institute of Medical Sciences and Research Centre. Fifty cervicofacial halves were used for this study. The following parameters were observed- number of trunks of the anterior division of facial nerve from the stylomastoid foramen and its distance upto its furcation point, number of ramus of facial nerve and the number of branches from each ramus, relation of facial nerve to retromandibular vein and communication of facial nerve’s terminal branches and its branching pattern. All the data was tabulated in the Microsoft Excel and the mean±standard deviation were calculated for all relevant distances of the trunk and the branches. Results: In all 50 specimens, one trunk of facial nerve entered the parotid gland and divided into two rami, namely temporofacial and cervicofacial rami. The distance of the trunk from stylomastoid foramen to its bifurcation point measured in the range of 0.8 to 1.8 cm, with a mean of 1.28±0.31 cm. In all the 50 specimens, temporal and zygomatic branches were given from temporofacial ramus and marginal mandibular and cervical branches were given from cervicofacial ramus. The buccal branch was given from both the rami in 42 specimens and from temporofacial ramus in eight specimens. The facial nerve was lateral to the retromandibular vein in 49 specimens. In one specimen, the retromandibular vein was present between facial nerve branches. Four types of branching pattern of facial nerve were observed. Type I was observed in eight specimens, Type II was observed in 20 specimens, Type III in 14 specimens and Type IV in eight specimens. Conclusion: To contribute to the field of anatomy of Facial nerve and its variations, this study was accomplished. Hence, promoting an integrated approach for a better clinical outcome.

Keywords

• branching pattern
• cervicofacial rami
• facio-venous plane
• stylomastoid foramen
• temporofacial rami