simply described the facial nerve its course and its diseases with its examination. Easy to understand and sufficient for MBBS level students.

1. FACIAL NERVE (ANATOMY,
EXAMINATION AND ITS
DISORDER)
BY:
SABIN BHANDARI

2. ANATOMY
• 7th cranial nerve is
a mixed nerve
containing motor,
taste,
secretomotor and
sensory fibers

3. COURSE OF FACIAL NERVE
• Can be divided into 3 parts :
1. Intracranial part
2. Intra-temporal part
3. Extra-temporal part

4. Intracranial part
• Nucleus of 7th nerve
are:
1. Brancial motor nucleus
2. Superior salivatory
nucleus
3. Nucleus of tractus
solitarus
4. Pontine trigeminal
nucleus
site: lower part of pons

5. • Brancial motor nucleus:
part of nucleus that
supplies the upper part
of face receives cortico-
nuclear fibers from both
cerebral hemisphere
but the nucleus that
supplies the lower part
of face receives only
from contralateral
cerebral hemisphere.

6. FIBERS NUCLEUS FUNCTION
Special visceral
efferent
Branchial motor
nucleus
(facial nucleus)
Innervates:
•Muscle of facial expression
•Stylohyoid
•Digastric (posterior belly
•Stapedius
General Visceral
efferent
(parasympathetic)
Superior salivatory
nucleus
Innervates:
•Lacrimal gland
•Submandibular gland
•Sublingual gland
•Small glands of nasal mucosa, hard and soft
palate, and dorsum of tongue
Special visceral
afferent
Nucleus of tractus
solitarus
Gustatory fibers from anterior 1/3rd of
tongue
General Somatic
afferent
Sensory nucleus of
trigeminal nerve
Sensory fibers from auricle, skin of EAC, outer
space of tympanic membrane

7. • 7th cranial nerve emerges in the
Cerebellopontine angle between the pons and
medulla
• Then enters into the Internal auditory canal.

8. Intra-temporal part
• From internal auditory canal to stylomastoid foramen.
• Further divided into :
1. Meatal segment: within internal acoustic meatus(8-
10mm)
2. Labyrinthine segment: from fundus of meatus to
geniculate ganglion where nerve takes a turn
posteriorly forming a ‘genu’. The nerve in this
segment has narrowest diameter (0.6-0.68 mm) and
the bony canal in this segment is also narrowest. Thus
edema or inflammation can easily compress the nerve
and cause paralysis. Shrotest segment : 4.0 mm

9. 3. Tympanic or horizontal
segment: It extends from
geniculate ganglion to
pyramidal eminance. It
lies above the oval
window and below the
lateral semicircular canal.
4. Mastoid or vertical
segment: It extends from
pyramidal eminence to
stylomastoid foramen.
Between the tympanic
and mastoid segment is
the second genu of the
7th nerve.
Geniculate ganglion : Greater Superficial
Petrosal Nerve supplies to lacrimal gland, nasal
gland, palatine gland, pharyngeal gland,
sinuses
Nerve to stapedius : motor fiber to stapedial
muscle
Corda tympanic: salivation and taste
sensation at anterior 2/3rd of tongue.

10. Extra-Cranial part
1. Posterior auricular : innervates extrinsic and
intrinsic muscles of outer ear, also consist of
sensory fibers to auricle.
2. Nerve to the posterior belly of Diagastric
3. Nerve to stylohyoid
After existing the stylomastoid
foramen the 7th nerve turns
superiorly to run just anterior
to outer ear where it gives out
3 branches:

11. • Temporofacial division gives
1. Temporal branch: innervates frontalis,
orbicularis occuli and Corrugator supercilli
2. Zygomatic branch: innervates orbicularis occuli
• Cervicofacial division gives
1. Buccal branch: innervates orbicularis oris,
buccinator
2. Mandibular branch: innervates mentalis muscle
3. Cervical branch: innervates platysma muscle
•Main trunk of facial nerve continues
anteroinferiorly into parotid gland giving
temporofacial and cervicofacial division

12. Blood supply of facial nerve
Derived from 4 blood vessels:
• Anterior inferior cerebellar artery-supplies the
nerve in CP angle
• Labyrinthine artery- supplies the nerve in
internal auditory canal
• Superficial petrosal artery- supplies geniculate
ganglion and adjacent region
• Stylomastoid artery- supplies mastoid
segment

13. Examination of facial nerve
MOTOR EXAMINATION
Inspection
• Observe the face bilaterally for any asymmetry
like unilateral:
1. Loss of frowning and wrinkles
2. Wide palpebral fissure
3. Epiphora
4. Loss of nasolabial fold
5. Drooping of angle of mouth and deviation of mouth to
opposite side
6. Drooling of saliva
• Observe spontaneous movement of face during eating,
speaking.

14. SN TESTS MUSCLES ACTING
1 Fixed the head and ask the patient to look at
your hand held above the patient’s head, see
the wrinkles over forehead
Frontal belly of
occipitofrontalis muscle
2 Ask patient to frown Currugator supercilliaris
3 Ask him to colse both eyes forcibly and you try
to force open the eyelids by your finger
Orbicularis occuli
4 Ask him to show his teeth- the angle of mouth
is drawn to healthy side
Levator anguli oris,
zygomaticus major and minor,
deppresor anguli oris,
buccinator and resorius
5 Ask him to blow out the cheeks against the
closed mouth. Now the both inflated cheeks
are pressed with fingers – air escapes from
mouth easily on the weak side
Orbicularis oris and buccinator
6 Ask the patient to purse the lip shut Only orbicularis oris

15. SENSORY EXAMINATION
For anterior 2/3rd part of tongue
• Prepare salt, sugar, sour, bitter solution
• Protude the tongue holding it with a gauge
• Put solution on anterior 2/3rd of tongue, 1
side at a time
• Ask patient to interpret the taste of solution
• Ask the patient to rinse the mouth after each
test

16. Hitzelberger’s Syndrome:
• It occurs due to 7th Cranial nerve involvement
in Acoustic Neuroma/ Vestibular schwanoma
• There is early involvement of the sensory
fibers which cause hypoesthesia of the
posterior meatal wall
For General Sensory

17. SECRETOMOTOR EXAMINATION
1. Schimer’s Test: for measure tear secretion
Procedure:
• Fold a strip of Whatman-41 filter paper 5mm from one
end
• Keep in the lower fornix at junction of lateral 1/3rd and
medial 2/3rd
• Ask the patient to look up and not to blink or close the
eye
• After 5 minutes of wetting of filter paper strip from the
bent end is measured
>15 mm: normal
5-10 mm: moderate to mild dry eye
<5 mm: severe dry eye
• Decreased lacrimation Indicates lesion above the
geniculate ganglion.

18. 2. Submandibular salivary flow test: for
measuring function of corda tympani
Procedure:
• Polythene tubes are passed into both
wharton’s duct.
• Drops of saliva counted during 1 minute
period.
• Decreased salivation shows injury above the
chorda tympani.

19. EXAMINATION OF REFLEXES
1. Stapedial reflex:
• It is tested by tympanometry.
• It is lost in lesion above the nerve to
stapedius

20. Facial Nerve paralysis
Causes
• Upper motor Neuron lesion
1. Brain abscess
2. Pontine gliomas
3. Poliomylites
4. Multiple sclerosis
5. Systemic disease: DM, Hyperthyroidism, HIV,
Syphillis, leprosy, leukemia
6. Cerbrovascular disease

21. • Lower motor neuron lesion
a) Intracranial part: (CP angle)
1. Meningioma
2. Acoustic neuroma
3. Congenital Cholesteatoma
4. Meningitis
b) Intra temporal part:
1. Idiopathic: Bells palsy, Melkerson’s Syndrome
2. Infection: ASOM, CSOM, Herpes zooster oticus,
malignant otitis externa

22. 3. Trauma: mastoidectomy, stapedectomy,
temporal bone fractures
4. Neoplasms: Facial nerve neuroma, malignancy
of external and middle ear, glomus jugulare
tumor, metastasis to temporal bone from CA
breast, bronchi or prostate
c) Extra temporal Part
1. Parotid gland surgery
2. Trauma in parotid region
3. Neonatal facial injury (forcep delivery)
4. Malignancy of parotid

23. Recurrent Facial Palsy Bells palsy (3-10%),
Melkerson’s Syndrome,
DM, sarcoidosis and tumors
Bilateral Facial Palsy Guillain-barre Syndrome,
Sarcoidosis, Sickle cell
anemia, Acute leukemia,
leprosy and other systemic
diseases

24. SN UMNL LMNL
UMNL is a lesion of neural
pathway above motor nuclei
of cranial nerve
LMNL is a lesion of motor
neurons located in cranial
nerve nucleus of brainstem or
below
SIGNS
1 Contralateral Lower face is
affected. Upper face spared.
Ipsilateral whole face is
affected.
2 Bells phenomenon never
occurs.
Bells phenomenon present.
3 Facial muscle are not atropied Fasciculation or muscle atropy
on the affected side.
4 Corneal reflex is preserved Corneal reflex is absent

25. Level of lesion Identification
At level of nucleus Identified by Associated
paralysis of 6th cranial nerve
At Cerebellopontine angle Presence of vestibular and
auditory defect and
involvement of other cranial
nerve such as V, IX, X, XI
At bony canal Topodiagnostic test (schirmer’s
test, stapedial reflex, taste test,
Submandibular salivary flow)
Outside the temporal bone Affects only the motor function
of nerve

26. House-Brackmann facial nerve
grading system
• Grade I - Normal
Normal facial function in all areas
• Grade II - Slight Dysfunction
Gross: slight weakness noticeable on close inspection;
may have very slight synkinesis
At rest: normal symmetry and tone
Motion: forehead - moderate to good function; eye -
complete closure with minimum effort; mouth - slight
asymmetry.

27. • Grade III - Moderate Dysfunction
Gross: obvious but not disfiguring difference between two
sides; noticeable but not severe synkinesis, contracture,
and/or hemi-facial spasm.
At rest: normal symmetry and tone
Motion: forehead - slight to moderate movement; eye -
complete closure with effort; mouth - slightly weak with
maximum effort.
• Grade IV - Moderate Severe Dysfunction
Gross: obvious weakness and/or disfiguring asymmetry
At rest: normal symmetry and tone
Motion: forehead - none; eye - incomplete closure; mouth -
asymmetric with maximum effort.

28. • Grade V - Severe Dysfunction
Gross: only barely perceptible motion
At rest: asymmetry
Motion: forehead - none; eye - incomplete
closure; mouth - slight movement
• Grade VI - Total Paralysis
No movement

29. Bell’s Palsy (idiopathic facial nerve
paralysis)
• Idiopathic LMN palsy of facial nerve of acute onset.
• Any age group may be affected though incidence rises with
age.
• Positive family history is present in 6-8% of patient
Etiology
1. Viral infection: Herpes simplex virus, Herpes zooster virus,
EB virus
2. Vascular ischemia:
• Primary ischemia- due to cold and stress
• Secondary ischemia- due to primary ischemia which
causes increase capillary permeability leading to
exudation of fluid, edema and compression of
microcirculation of nerve

30. 3. Heriditary
4. Autoimmune disorder
Clinical Features:
1. Sudden onset of weakness/paralysis on one side
of face: features of LMNL
2. Bells phenomenon: On attempting to close the
eye, the eyeball turns to upward and outward
3. Pain in the ear may precede / accompany nerve
paralysis
4. Paralysis may be complete or incomplete
5. Bells palsy is recurrent in 3-10% of patient

31. Diagnosis
• Diagnosis is always by exclusion.
• Careful history, complete otological and head
and neck examination
• Blood- CBC, ESR, Blood glucose level, Serology
• X-ray of mastoid bone
• Nerve excitability test
• For localizing the site of lesion
(topodiagnosis): Stapedial reflex, Schirmer’s
test, Submandibular salivary flow test, taste
test

32. Treatment
General
• Reassurance
• Releif of ear pain: analgesic
• Care of eye: to prevent exposure keratitis by wearing
dark googles, Voluntary closure @ 2 times/min
• Physiotherapy or massage of facial muscle
Medical
• Prednisolone (drug of choice): 1 mg/kg daily and
tappered in 2-3 weeks
• Ciprofloxacin eyedrop 2 hoursly and ointment HS at
night
• Electric stimulation of facial nerve

33. Surgical
• Nerve decompression releives pressure on the
nerve fibre and improves microcirculation of
nerve. Vertical and tympanic segment of
nerve are decompressed
• Neurorrhaphy (nerve repair):
1. Direct end to end anastomosis
2. Interpostion cable grafting: sural nerve,
greater auricular nerve
Prognosis: 85-90% full recovery

34. Melkersson’s Syndrome
• It is a idiopathic disorder consisiting triad of
Facial paralysis, swelling of lips and fissured
tongue
• Paralysis may be recurrent
• Treatment same as bells palsy

35. Herpes zooster Oticus (Ramsey-Hunt
Syndrome)
• Caused by varicella zooster virus
• Occurs in adult
• Traid of SNHL (8th Cranial N.), Vertigo and Facial Nerve
palsy (7th Cranial N.)
• May be associated with fever, severe earache, vesicular
eruption in auricle and EAC.
Treatment:
• Acyclovir 200-400 mg 5 times a day for 7 days
• High dose oral steroids
• If patient has vertigo: labyrinthine sedatives likes
cinnarazine, proclorperazine

36. Fracture of Temporal Bone
• May be transverse, longitudnal or Mixed
• Facial nerve palsy is most commonly seen in
Transverse fracture : 50%
Cause: Due to intraneural hematoma , compression
by a bony spicule or transection of nerve
Treatment: Delayed onset: conservatively same as
Bell’s palsy
Immediate onset: May require surgery
in the form of decompression, re-anastomosis of
cut ends or caval nerve graft

38. Ear or Mastoid Surgery
• Facial nerve is injured during stapedectomy,
tympanoplasty or mastoid surgery.
• Paralysis may be intermediate or delayed.
• Treatment is as same as in temporal bone
trauma.
• Sometimes, nerve is paralyzed due to pressure
packing in the exposed nerve and this should
be releived first

39. Operative injuries can be avoided by:
• Anatomical knowledge of course of facial nerve
and its surgical landmarks. Always work along the
course of nerve and never across it.
• Constant irrigation while drilling to avoid thermal
injury
• Gentle handling of nerve while it is exposed.
• Avoiding any pressure instruments in the nerve.
• Not to remove any granulations that penetrate
the nerve.
• Using magnification, never to work on facial
nerve without an operating microscope

40. Parotid surgery and trauma to facial
nerve:
• Facial nerve may be injured in the surgery of
parotid tumors or deliberately excised in
malignant tumors.
• Accidental injury in the parotid region can also
cause facial paralysis.
Treatment: re-anastomosis of cut end or caval
nerve grafting

41. Neoplasm
Intratemporal neoplasm:
• Carcinoma of external or middle ear, glomus
tumor, rabdomyosarcoma and metastatis tumor
of temporal bone all results in facial paralysis.
• Facial nerve neuroma occurs anywhere along
the course of nerve and produces paralysis of
gradual or sudden onset. High resolution CT-
scan and Gadolinium-enhanced MRI is very
useful for facial nerve tumor.
• It is treated by excision and nerve grafting.

42. Complication following Facial Paralysis
1. Incomplete recovery
2. Exposure Keratitis
3. Synkinesis (mass movements)
4. Tics and spasms
5. Contractures
6. Crocodile tears (gustatory lacrimation)
7. Freys Syndrome (gustatory sweating)
8. Psychological and social problem

43. References
• Disease of ear nose and throat.
PL. Dhingra, Shruti Dhingra
• An illustrated text book ear nose and throat and head and
neck surgery
Rakesh Prasad Shriwastab
• Atlas of Anatomy, Thieme,Stuttagard, New york
• Clinical Neuroanatomy, Richard S. Snell, 7th Edition
• https://medicine.yale.edu/cranialnerves/nerves/facial/
• https://bmc.med.utoronto.ca/cranialnerves/wp-
content/images/c_07/
• https://sorensenclinic.com/microsurgery/house-
brackmann/