ABSTRACT
Smile is one of the most natural and important expressions of human emotion. Man uses
his lips mainly to register his emotions. Thus, the slightest asymmetry or weakness
around the lips and mouth may transform this pleasant expression into embarrassment
and distortion. The circumoral musculature, the major part of which is supplied by
the marginal mandibular branch of the facial nerve, is the main factor in this expression.
Therefore, an injury to this nerve during a surgical procedure can distort the expression
of the smile as well as other facial expressions. This nerve often gets injured by
surgeons in operative procedures in the submandibular region, like excision of the
submandibular gland due to lack of accurate knowledge of variations in the course,
branches and relations. In the present study, 50 facial halves were dissected to study
the origin, entire course, termination, branches, muscles supplied by it, its anastomoses
with other branches of facial nerve on the same as well as on the opposite side and
its relations with the surrounding structures. The marginal mandibular branch of the
facial nerve was found superficial to the facial artery and (anterior) facial vein
in all the cases (100%). Thus the facial artery can be used as an important landmark
in locating the marginal mandibular nerve during surgical procedures. Such a study
can help in planning precise and accurate incisions and in preventing the unrecognized
severance of this nerve during surgical procedures.
KEY WORDS
Facial nerve - marginal mandibular nerve - smile distortion
