Triangle of Marginal Mandibular Branch (MMB): Anatomical Zone, Constant Reference of the MMB in Cervical Surgical Position

Abstract

Summary: The purpose of this study is to reduce the search area of the marginal mandibular branch, this scarecrow nerve of the upper cervical surgery. Materials and methods: MMB dissection was applied to 25 anatomical subjects, who described an ABC Triangle where the MMB is still inside the cervical surgical position: A mandibular angle, B intersection of the MMB with the lower border of the mandible (LBM), C the position of the furthest MMB below the LBM. Results: This nerve is still depth of the superficial cervical fascia, and its division is constantly after the intersection with the facial vein (FV). The position of the MMB furthest from the LBM is found between 2 and 2.2 cm below the LBM and at 2/3 of the distance AX from the angle of the mandible angle to the intersection of the FV with the LBM. This distance AX represents the 2/3 of the distance AB from the angle of the mandible to the intersection of the MMB with the LBM and whose measurement is between 4 and 4.5 cm. Conclusion: This triangle ABC landmark of MMB provides reliable and constant anatomical markers allowing the surgeon locating or avoidance of MMB.