The facial nerve emerges from the brainstem and has both motor and sensory functions. It innervates the muscles of facial expression and provides parasympathetic innervation to glands. Facial paralysis can result from lesions to the facial nerve. Bell's palsy is the most common cause of unilateral facial paralysis and usually resolves over time with treatment like corticosteroids. Grading systems like the House-Brackmann scale are used to assess facial nerve function.

1. Facial Nerve and Palsy
Musa Abu Sabha

2. Facial nerve
• The facial nerve is the seventh (VII) of twelve paired
cranial nerves.
• It emerges from the brainstem between the Pons and
the Medulla.

4. • Nuclei:
1. Facial nucleus - Special Visceral Efferent (SVE).
2. Superior salivary nucleus – General Visceral Efferent (GVE).
3. Lacrimatory nucleus - General Visceral Efferent (GVE).
Facial nerve is a mixed nerve, having 2 roots:
1. Medial motor root.
2. Lateral sensory root (nervous intermedius),which contains
sensory & parasympathetic fibers.

6. Function:
1. Motor function:
– Muscles of facial expression.
– Posterior belly of digastrics muscle.
– Stylohyoid muscle.
– Stapedius muscle of the middle ear.
2. Sensory function:
– Taste sensations from the anterior two-thirds of the tongue.
– Oropharynx above the palatine tonsil.
3. Secretomotor function (parasympathetic innervation):
– Submandibular & sublingual salivary glands.
– Lacrimal glands.
– Nasal glands.

7. Course
• The motor part arises from the facial nerve nucleus in the
pons.
• Sensory part arises from the nervus intermedius.
• The two roots emerge from the anterior surface of the
brain between the pons and Medulla oblongata.
• They pass laterally & forward in the posterior cranial
fossa to opening of the internal acoustic meatus.
• At the bottom of the meatus, the nerve enters the facial
canal & runs laterally above the vestibule of the labyrinith
until it reaches the medial wall of the tympanic cavity.
Cont…

8. Course

9. Here, the nerve expands from the sensory geniculate ganglion
to give:
• Branches inside the facial canal:
1. Greater petrosal nerve : provides parasympathetic
innervation to lacrimal gland, as well as special taste sensory
fibers to the palate via the nerve of pterygoid canal (Vidian
Nerve).
2. Nerve to stapedius : provides motor innervation for
stapedius muscle in middle ear.
3. Chorda tympani : provides parasympathetic innervation to
submandibular gland, sublingual gland and special sensory
taste fibers for the anterior 2/3 of the tongue.

10. Then it descends in the posterior wall of the middle ear, behind the
pyramid, then through the stylomastoid foramen & passes through the
parotid gland. Though it passes through the parotid gland , it doesn’t
innervate it.
• Branches distal to stylomastoid foramen:
1. Posterior auricular nerve: controls movements of some
of the scalp muscles around the ear.
2. Branch to Posterior belly of Digastric and Stylohyoid
muscle.

11. • As the facial nerve runs forward within the substance of the
parotid gland, it divides into its 5 terminal branches:
1. Temporal branch
2. Zygomatic branch.
3. Buccal branch.
4. Mandibular branch.
5. Cervical branch.
** Mastidectomy to remove cholesteatoma carries a risk of
facial paralysis.

12. Testing the facial nerve:
 Voluntary facial movements, such as:
• Wrinkling the brow
• Showing teeth
• Frowning
• Closing the eyes tightly
• Pursing the lips
• Puffing out the cheeks
There should be no noticeable asymmetry.

13. Facial Paralysis

14. • UMN lesion:
In an UMN lesion, called central seven, only the lower
part of the face on the opposite side will be affected,
due to the bilateral control to the upper facial muscles.
• LMN lesion:
LMN lesions can result in Bell's palsy, manifested as
both upper and lower facial weakness on the same side
of the lesion.

17. Bell's palsy
• The most common cause of unilateral facial paralysis. Bell palsy
is an acute, unilateral, peripheral, lower-motor-neuron facial-
nerve paralysis that gradually resolves over time in 80-90% of
cases.
• The cause of Bell palsy remains unknown, though it appears to
be a polyneuritis with possible viral, inflammatory, autoimmune,
and ischemic etiologies. Increasing evidence implicates herpes
simplex type I and herpes zoster virus reactivation from cranial-nerve
ganglia.

18. • should be conservative and guided by the severity and
probable prognosis in each particular case.
• Studies have shown the benefit of high-dose corticosteroids
for acute Bell palsy.
• Although antiviral treatment has been used in recent years,
evidence is now available indicating that it may not be
useful.
Treatment of Bell palsy

19. House Brackmann facial nerve grading
system

20. House Brackmann facial nerve
grading system

21. House Brackmann facial nerve
grading system

22. Waardenburg syndrome

23. Waardenburg syndrome
• Autosomal dominant disorder with an incidence of 1 in
40,000 that manifests with sensorineural deafness,
pigmentation defects of the skin, hair and iris and
various defects of neural crest-derived tissues.

24. Case Report

25. Case Report

26. Conclusion