A 55-year-old woman has undergone facial surgery for the excision of a malignant parotid tumor. A week postoperatively, marked weakness is seen in the musculature of the patient's lower lip. Which of the following nerves was most likely injured during the parotidectomy?
High-Yield Explanation
The anterior division of the facial nerve passes through the parotid gland and is therefore at risk during surgery of the parotid gland. Since this patient's symptoms involved paralysis of the muscles of the lower lip, the branch of the facial nerve that supplies these muscles, the marginal mandibular branch, is the one that has suffered the iatrogenic injury.