The marginal mandibular branch of the facial nerve arises from the facial nerve (CN VII) in the parotid gland at the parotid plexus.

It passes anterior-ward deep to the platysma and depressor anguli oris muscles.

[citation needed] The marginal mandibular 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.

Thus the facial artery can be used as an important landmark in locating the marginal mandibular nerve during surgical procedures.

[3] This article incorporates text in the public domain from page 905 of the 20th edition of Gray's Anatomy (1918)