Facial Nerve

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Questions and Answers

What is a possible consequence of damage to the facial nerve due to intracranial lesions?

Loss of taste on the anterior 2/3 of the tongue (correct)

Excessive salivation

Severe headaches and migraines

Increased taste sensitivity on the posterior tongue

Which of the following conditions can lead to paralysis of the muscles of facial expression due to extrinsic factors?

Stroke

Nerve compression

Neuropathy

Tumor of the parotid gland (correct)

What role does the facial nerve play beyond motor supply to facial expression?

Taste to the posterior one-third of the tongue

Sensory innervation to the ear

Primary sensation to the scalp

Parasympathetic innervation to salivary glands (correct)

Which of the following is NOT a symptom of damage to the facial nerve?

Loss of facial sensation Signup and view all the answers

Which infection is particularly known to affect the facial nerve?

Herpes virus infection Signup and view all the answers

What is the primary function of the motor root of the facial nerve?

Innervation of muscles responsible for facial expression Signup and view all the answers

Which of the following glands is NOT directly innervated by fibers of the facial nerve?

Parotid gland Signup and view all the answers

What structure does the facial nerve enter after passing through the internal auditory meatus?

Facial canal Signup and view all the answers

Which branch of the facial nerve contains parasympathetic fibers for tear production?

Greater petrosal nerve Signup and view all the answers

The facial nerve is responsible for providing taste sensation to which part of the tongue?

Anterior 2/3 of the tongue Signup and view all the answers

What is the role of the nerve to stapedius within the function of the facial nerve?

Dampens loud sounds in the middle ear Signup and view all the answers

During its anatomical course, which section describes the facial nerve when it is just outside the cranium?

Extracranial course Signup and view all the answers

Which facial expression-related muscle does the facial nerve NOT innervate?

Sternocleidomastoid Signup and view all the answers

What is the function of the chorda tympani?

Innervates the anterior 2/3 of the tongue with taste Signup and view all the answers

Which branch of the facial nerve supplies the platysma muscle?

Cervical Branch Signup and view all the answers

Which branch of the facial nerve is mainly involved in facial expression around the forehead?

Zygomatic Branch Signup and view all the answers

What structure does the facial nerve exit the cranium through?

Stylomastoid foramen Signup and view all the answers

Which muscle does the mandibular branch of the facial nerve specifically innervate?

Mentalis Signup and view all the answers

The temporal branch of the facial nerve supplies which of the following muscles?

Corrugator supercilii Signup and view all the answers

What does the posterior auricular nerve innervate?

Occipital part of the occipitofrontalis muscle Signup and view all the answers

Which of the following is NOT a branch of the facial nerve emerging from the parotid gland?

Otic branch Signup and view all the answers

Study Notes

Facial Nerve Overview

The facial nerve (CN VII) is a cranial nerve
It has a dual role - motor function and sensory function
It controls muscles of facial expression
It plays a role in taste, and other sensory functions
The facial nerve emerges from the brain between the pons and medulla.

Facial Nerve Roots

The facial nerve has two roots:
- A larger motor root originating from the motor nucleus
- A smaller root, called the nervus intermedius, which has some sensory functions

Facial Nerve Pathways

The facial nerve passes into the internal auditory meatus.

Facial Nerve Motor Functions

Facial nerve motor functions innervate muscles that control facial expressions
The nerve innervates muscles including (e.g., temporalis, orbicularis oculi, zygomaticus, masseter buccinator , risorius, platysma)

Facial Nerve Sensory Functions

The nervus intermedius (a branch of the facial nerve) transmits taste information from the anterior two-thirds of the tongue.
It also carries sensory information from the external ear.

Facial Nerve Parasympathetic Functions

The facial nerve has parasympathetic function
It supplies the sublingual and submandibular salivary glands.
It also supplies mucous glands of the nasal cavity, paranasal sinuses, palate and lacrimal gland for tear production.

Anatomical Course

The facial nerve's course is divided into two parts:
- Intracranial: the nerve travels through the cranial cavity
- Extracranial: the nerve travels through the face and neck after exiting the skull.

Branches of the Facial Nerve

The facial nerve exits the skull via the stylomastoid foramen
It gives off many branches in the parotid gland
- Temporal branch
- Zygomatic branch
- Buccal branch
- Marginal mandibular branch
- Cervical branch
Each branch serves a specific group of muscles or sensory areas.

Function of Branches

Temporal nerve supplies auricular muscles, frontalis, orbicularis oculi, and corrugator supercilii.
Zygomatic nerve innervates orbicularis oculi, and contributes to muscles of the upper lip and nose..
Buccal nerve innervates orbicularis oris, buccinator, zygomaticus.
Marginal mandibular nerve supplies depressor labii inferioris, depressor anguli oris, and mentalis.
Cervical nerve supplies platysma muscle.

Intracranial Lesions - Causes

Infections (related to the outer or middle ear)
Stroke

Damage and Symptoms

Facial nerve damage can result in facial paralysis or weakness.
Damage can also result in sensory loss (e.g., loss of taste, dry mouth), difficulty talking

Extracranial Lesions - Causes

Parotid gland pathology (e.g., tumor, parotitis, surgery)
Infection (often herpes virus)

Trigeminal and Facial Nerve Examination

A planned examination procedure for the trigeminal and facial nerves.

Summary

The facial nerve is crucial for facial movement, taste, and parasympathetic functions.
The nerve has a complex path involving cranial and extracranial components.
Damage to the nerve has distinct symptoms depending upon location and cause

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