Examination of the branches of the facial nerve emerging from the parotid gland in fetuses

After the facial nerve leaves the parotid gland, it innervates the mimic muscles. Distribution patterns of these branches that facial paralysis seen injury are variable. In this study, it is aimed to examine the morphological and morphometric features of the branches of the facial nerve after leaving the parotid gland. In the study, 30 sides of 15 fetuses (10 female, 5 male) were dissected. The branches of the facial nerve emerging from the parotid gland were exposed and statistical analysis of the obtained data was performed. The number of branches of the facial nerve after leaving from the parotid gland and the localization of the branches were determined by reference to different lines. Dangerous zones were detected on the lines determined for the frontotemporal branch and marginal mandibular branch. It was determined that RFT crossed the line between 11% and 49% of length of line A and between 16% and 63% of length of line B. It was determined that the zygomatic branch was most frequently between the B and C lines, and the buccal branch was most frequently below the ductus parotideus (51.1%). After the marginal mandibular branch emerged from the parotid gland, 11 types were determined as result of the classification based on the number of branches. The most common pattern was determined to be type 1a (40.7%). The rates of crossing points of the facial artery and facial vein of branches marginal mandibular were found in 24% to 52% and 17% to 49% of the length of the lower border of the mandible, respectively. The exit point of the cervical branch from the parotid gland was most commonly found below the E line (91.1%). The point where the cervical branch entered the platysma was most frequently found in front of the X line (92.5%). This study provides quantitative datas according to the branching pattern and reference points of the branches of the facial nerve leaving the parotid gland. Determining the localization of nerve branches should be considered in surgical applications to be applied on the face and neck. It is thought that this study will contribute to the literature on facial nerve in fetuses and it will guide the surgeries applied to this region in childhood.