The FASEB Journal
The most frequent cause of damage and paralysis to the facial nerve is iatrogenic injury during operations in the parotid or submandibular regions, and the marginal mandibular branch (MMBr) is the least likely to recover due to its infrequent anastomosis with other branches. Literature has stated that the MMBr courses superior to the inferior border of the mandible more often than in the submandibular region. However, various studies report conflicting results, and variations in location have been seen between embalmed and fresh specimens. The purpose of this study was to determine the location of the MMBr in relation to the inferior border of the mandible in embalmed specimens and compare those findings with fresh specimens. In both embalmed and fresh cadavers, the superficial fascial planes were dissected to reveal the MMBr and its anatomical relationships and distances. Perpendicular distance between the most inferior branch of the MMBr and the antegonial notch were measured on both sides to the nearest 0.01mm using a caliper. The most inferior position of the MMBr between the antegonial notch and gonion was also measured. A negative value was used to denote branches superior to the inferior border of the mandible, and positive values for those below. This study found that the MMBr was located below of the border of the mandible more often than above. There was also no significant difference in MMBr location between fresh and embalmed cadavers. These results indicated that the MMBr postion was more inferior than initially stated, and that there was no significant change in the location of the nerve due to the embalming process.
Marolt C, Freed B, Johnson KS, Rowe J, Coker C, Steele R, Stephens R, Surek CC. Relation of the Marginal Mandibular Nerve to the Inferior Border of the Mandible in Fresh and Embalmed Cadavers. The FASEB Journal. 2020; 34(S1). doi: 10.1096/fasebj.2020.34.s1.03473.