Reply: Vascular and Nerve Relations of the Marginal Mandibular Nerve of the Face: Anatomy and Clinical Relevance

Sir: I thank Dr. Robinson and colleagues for the attention afforded to our article.1 My coauthors and I did not explicitly define “safe zones,” but our work allowed us to document the variations of the marginal mandibular branch of the facial nerve. Proper knowledge of the trajectory and of the variations allows safe zones to be deduced. Moreover, there have been numerous studies defining safe zones for the facial nerve.2,3 They rightly note that age and gravity modify the landmarks of the facial nerve. One of our ongoing studies is, in fact, in regard to the modifications linked with age. This comment allows me to emphasize the relevance of taking the facial pedicle as a landmark, since the topography of the marginal mandibular nerve of the facial nerve is not influenced either by age or by gravity. The variations of the facial nerve in the same individual from one side to the other are known. We did not describe the variations in the same individual in “only two of 62 hemifaces,” which would not make much sense. We did not study the variations in the same individual, but from one individual to another. We used halfheads simply because that is how they are provided to us by the laboratory. Matching was sometimes possible, but the number of certain matches would not have allowed us to draw reliable conclusions regarding the variations from one side to the other in the same individual. In terms of the diameters of the branches of the marginal mandibular nerve of the facial nerve, we did not take any measurements, but it seemed to us that the greater the number of branches the thinner they were. Thus, in Figure 3 of the article,1 where there is a single marginal mandibular nerve, it had a diameter greater than the one in Figure 9, where the nerve gave rise to numerous branches. The aim of the study was to show the variations of the marginal mandibular nerve of the facial nerve relative to the facial artery and vein. The correspondence from Dr. Robinson and colleagues underscores the key messages of the article and it has allowed me, I hope, to provide clarifications and to emphasize the independence of the relationships of the facial artery, the facial vein, and the marginal mandibular nerve of the facial nerve with age. Although the facial nerve has been studied extensively, this correspondence shows that anatomical studies continue to be of relevance and they indicate further avenues of research. I am grateful for their views. DISCLOSURE The author has no financial interest to declare in relation to the content of this communication. Gaoussou Touré, M.D., Ph.D.Maxillofacial and Facial Plastic SurgeryIntercity Hospital Villeneuve Saint GeorgesVilleneuve, FranceANCRE–URDIAParis Descartes UniversityParis, France