Marginal mandibular branch of the facial nerve in human fetuses.

OBJECTIVES: To observe the course of the marginal mandibular branch (MMB) and its relation to the inferior border of the mandible and facial vessels.

METHODS: This study was conducted in the Department of Anatomy, Gulhane Military Medical Academy, Etlik, Ankara, Turkey from February 2009 to April 2010. The 44 hemi-face specimens of 22 fetuses were selected for this study, and dissected under a stereomicroscope. The MMB relationship was evaluated between adjacent structures (like vessels and muscles) and the lower border of the mandible.

RESULTS: We found a number of one to 4 branches of the MMB. The MMB ran laterally to the facial vein in 42 (95.5%) of the 44 specimens. All the branches of the MMB ran laterally to the facial artery in 30 (68.2%) of the 44 specimens. In 2 specimens, it ran medially to the facial artery. In 10 specimens, the facial artery ran between 2 branches of the MMB. In 2 specimens, the 2 branches of the MMB ran between facial artery and vein. There were no statistical differences between the left and right sides, and in both genders.

CONCLUSIONS: The inferior border of the mandible may be an important landmark to avoid injury to the MMB of the facial nerve. It is for this reason, that surgeons who are willing to operate on this area should have a true knowledge and accurate judgement regarding the anatomy of this branch.