Branches of the Facial Nerve and Their Distribution

Introduction

The facial nerve (cranial nerve VII) is a mixed nerve with both motor and sensory functions. It plays a crucial role in facial expression, taste sensation, and certain autonomic functions.

Anatomy and Branches

Intracranial Course

The facial nerve originates from the brainstem at the pontomedullary junction, passing through the internal acoustic meatus.

Extracranial Branches

Once it exits the skull via the stylomastoid foramen, it gives rise to several motor branches:

• Temporal Branch - Controls muscles of the forehead and upper eyelids.
• Zygomatic Branch - Innervates muscles around the eyes.
• Buccal Branch - Controls muscles of the cheeks and lips.
• Mandibular Branch - Innervates muscles of the lower lip and chin.
• Cervical Branch - Controls the platysma muscle in the neck.

Motor and Sensory Functions

Motor Functions

The facial nerve primarily supplies motor innervation to facial muscles involved in expressions such as smiling, frowning, and blinking.

Sensory Functions

It carries taste sensations from the anterior two-thirds of the tongue via the chorda tympani branch.

Clinical Significance

Damage to the facial nerve can result in facial paralysis, Bell's palsy, or difficulty in closing the eyelids.