The<unk><unk>  nerve may be injured during surgery in the neck region, especially during excision of the submandibular salivary gland or during neck dissections due to lack of accurate knowledge of variations in the course, branches and relations. An injury to this nerve during a surgical procedure can distort the expression of the smile as well as other facial expressions. The<unk>  is found superficial to the facial artery and (anterior) facial vein. Thus the facial artery can be used as an important landmark in locating the<unk><unk>  nerve during surgical procedures. Damage can cause paralysis of the three muscles it supplies, which can cause an asymmetrical smile due to lack of contraction of the depressor labii inferioris muscle. This may be corrected with resection of the muscle, which tends to be successful.
Marginal mandibular branch of the facial nerve
Buccal branches of the facial nerve
Auriculotemporal nerve
Nerve of pterygoid canal
Supratrochlear nerve
Oculomotor nerve
Long thoracic nerve
Olfactory nerve