Applied anatomy of the intraoral approach for masseter nerve

doi:10.3969/j.issn.1673-7040.2014.11.009

Abstract：Objective To further explore the intraoral anatomy of masseter nerve and adjacent tissues, providing anatomical basis for masseter nerve amputation in masseter hypertrophy therapy.Methods:12 adult cadaver specimens was fixed in formalin for over a year.The specimens were sagittal split from the middle. 23 sides was got and removed the skin and subcutaneous tissue on the head and face.Masseter muscle was exposed.Masseter bottom was peeled from the mandible.Methods Malar bone was sawed off at the leading and trailing edges of masseter muscle.Masseter space was exposed by flipping masseter disc backwards.The position where masseter nerve trunk gets into the masseter muscle was finely separated.The shape of masseter nerve trunk in the masseter muscle was carefully separated.The measurement data was sta-tistically analyzed.Results Masseter nerve was on the inside of the masseter muscle,getting into the masseter space from the trailing edge of temporal tendon,going through the masseteric fascia,gradually deep into the muscle.About (8.86 ± 3.07)mm going through the masseteric fascia,two masseter nerve branches was formed,paralleling with the masseter blood vessels.The distance between the trailing edge of temporal tendon and the masseter nerve branching point was left side (9.84±2.88)mm,right side (7.88 ±3.08)mm. The distance between the trailing edge of temporal tendon and leading edge of masseter zygomatic attach-ment point was left side (56.14±3.33)mm,right side (56.23±4.35)mm.The distance between the trailing edge of temporal tendon and the mandibular notch was:left side (12.70±2.5 1)mm,right side (1 1.30±3.31)mm.The distance between the trailing edge of temporal tendon and the mandibular ra-mus front cavity was:left side (38.09±5.00)mm,right side (36.48±5.32)mm.Left and right facial masseteric nerve comparision of distances between masseter nerve and respective anatomical point was not significantly different.Conclusion The shape of masseter nerve is stable,surrounded by typical ana-tomical landmarks.Thus the intraoral approach to expose masseter nerve is feasible,that can be de-signed for masseter nerve amputation in masseter hypertrophy.