The facial nerve can be injured during the head and neck surgery or any rhytidectomy procedures, so the surgeon must be familiar with its normal relationships to various surface landmarks in the face.
For several decades the surgical anatomy of the facial nerve in the parotid area has been very well documented by many authors and the frontal and mandibular branches, which are most vulnerable to injury during head and neck operation, also studied by many other authors. But strangely enough there have been significant discrepancies between the results of studies of each authors.
The purpose of this study is to declare the types of facial nerve branching in the face and the anatomical relationships of the frontal and mandibular branches to the superficial structures of face in Korean adult cadevars.
After surgical dissections of 46 facial halves we have obtained following results;
1. Types of facial nerve branching (according to Davis’ classification) are as follows; Type Ⅰ 0.0%, Type Ⅱ 4.4%, TypeⅢ 21.7%, Type Ⅳ 8.7%, Type Ⅴ 30.4%, and Type Ⅵ 34.8%.
2. The number of rami of the frontal branch of facial nerve is from 1 to 5 and the mean number of rami is 2.7.
3. The distance from point Z (a crossing point which is made by a vertical line from the auricule-scalp junction and horizontal line of superior border of the zygomatic arch) to the most anterior ramus is from 1.5cm to 4.8cm and the mean is 3.2cm. The distance from point Z to the most posterior ramus is from 1.1cm to 3.5cm and the mean is 2.3cm.
4. The width of the frontal branch (the distance from the most anterior ramus to the most posterior ramus) at the superior border of the zygomatic arch is from Ocm to 2.6cm and the mean is 0.9cm.
5. The frontal branches of the facial nerve lie anteriorly to the frontal branch of the superficial temporal artery in 95.7% and posteriorly in 4.3%.
6. The number of rami of the mandibular branch of facial nerve is from 1 to 4 and the mean is 2.4.
7. The mandibular branches are above the lower mandibular border in 60.9% and below in 39.1%.
8. Of the 18 cases of mandibular branch which lie below the lower mandibular border 8 cases lie at the facial artery within 5mm below the lower mandibular border, 8 cases in the range from 5mm to 10mm, and 2 cases longer than 15mm.
9. The mandibular branches of the facial nerve have an anastomosis to the buccal branches in 17.4%.
In discussion we have compared the results of this study with other author’s one and tried to obtain warning anatomical points that demand special attention to avoid facial nerve branch injuries during facial surgery.
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