Facial Nerve Branches Anatomy
1. Main trunk of facial nerve emerging from stylomastoid foramen
2. Cervical branch
3. Marginal mandibular branch
4. Buccal branches
5. Zygomatic branches
6. Temporal branches
Comment: The main trunk of the facial nerve exits through the stylomastoid foramen and, after giving off several small branches, courses through the substance of the parotid gland. It ends as a plexus of 5 major terminal branches that innervate the muscles of facial expression.
The 5 groups of terminal branches are the temporal, zygomatic, buccal, marginal mandibular, and cervical branches. A mnemonic— To Zanzibar By Motor Car (named from superior to inferior)—might help in remembering the names of these 5 terminal branches.
Clinical: An infection, usually caused by the herpes simplex virus, of the facial nerve (CN VII) can cause acute unilateral paralysis of the muscles of facial expression, a condition called Bell’s palsy. Facial expression on the affected side is minimal. For example, it is difficult to smile or bare one’s teeth; the mouth is drawn to the unaffected (contralateral) side; and the person cannot wink, close the eyelid, or wrinkle the forehead on the affected side. Often, over time, the symptoms will disappear, but this may take weeks or months to occur.