#facialnerve #bell's plasy

1. Facial nerve
Unit head –Dr. Prabhat
Kanvriya
Presented by-Dr. Roopsingh
Department of medicine
SNMCjodhpur

2. Outline-
• Introduction
• Anatomy
• Clinical examination –Examination of motor system
-Examination of Reflex
-Examination of sensory system
-Examination of secretory function
• Disordes-facial weakness
• Localization of facial nerve palsy

3. Introduction-
• Mixed nerve with motor and sensory roots.
• Facial nerve is seventh cranial nerve
• Emerges from the brain stem between the pons and medulla,
controls muscles of facial expression, and muscles of the scalp and
ear, as well as buccinator, platysma, stapedius, stylohyoid, and
posterior belly of the digastric.
• Functions in conveyance of taste sensations from the anterior two
thirds of the tongue and oral cavity

4. Cont..
• Carries parasympathetic secretory fibers to submandibular and
sublingual salivary glands, lacrimal gland and to mucous membranes
of oral and nasal cavities.
• Conveys exteroceptive sensation from eardrum and external auditory
canal, proprioceptive sensation from muscles it supplies, and general
visceral sensation from salivary glands and mucosa of the nose and
pharynx.

5. ANATOMY-Facial nerve has mainly two parts-
1. Facial nerve
proper(Motor)
2. Nervus
intermedius

6. {1} Facial nerve proper (motor):
Arising from facial motor nucleus in pons.
Supranuclear innervation to the muscles of facial expression
arises from the lower third of contralateral precentral gyrus in
facial area of motor homunculus.
Portion of nucleus that innervates the lower half to two thirds
of the face has predominantly contralateral supranuclear
control;
Portion that innervates upper third to half has bilateral control.

7. Facial nucleus is special visceral efferent, or branchiomotor;
It innervates the muscles of the second branchial arch
Facial motor nucleus has lateral, medial, and dorsal subnuclei,
arranged in columns.
Exits the pons laterally at the pontomedullary junction, just caudal
to the roots of CN V between the olive and the inferior cerebellar
peduncle
Has two components, motor root, which makes up about 70% of
the fibers, and sensory root, which accounts for 30%.

8. facial nerve
in pons

10. 2 .Nervus intermedius:
• Sensory and autonomic component of the facial nerve.
• Runs in a position intermediatebetween CNs VII and VIII across the CPA
• At first external genu, NI fuses with the geniculate ganglion.
• Sensory cells located in the geniculate ganglion are general somatic
afferent (GSA) and special visceral afferent (SVA)

11. Course and
relations:
1. • Intracranial
(intrapetrosal) course
2. • Extracranial course

14. (1)Within the facial canal-
1- Greater superficial petrosal nerve (GSPN) :
• carries preganglionicparasympatheticfibers
• These fibers are conveyed by the NI to geniculateganglion.
• Pass through the ganglionwithoutsynapsing into the greater petrosal
nerve, which goes forward through the hiatusof the facialcanal to join
deep petrosalnerve from the carotid sympatheticplexus to form the
vidian nerve, or the nerve of the pterygoid canal, which runs to the
sphenopalatineganglion,from where postganglionicfibers proceed to
the lacrimalgland.
2-Nerve to stapedius: supplies the stapedius muscle

15. Conte….
•3- Chorda tympani nerve:
• • It arises from the facial nerve 6 mm above the stylomastoid
foramen and runs upwards to perforate the posterior bony wall of
the tympanic cavity
• . • It carries taste and general visceral afferent (GVA) fibers as well as
preganglionic parasympathetics.

16. (II)- At exit from the stylomastoid foramen
• 1- Posterior auricular nerve: Supplies the occipitalis , posterior
auricular, and transverse and oblique auricular muscles.
• 2- Digastric branch: Posterior belly of digastric muscle
• 3-Stylohyoid branch: Stylohyoid muscle

17. (III) IN FACE
• A. Temporal
• B Zygomatic
• C Buccal
• D Marginal mandibular
• E Cervical

18. GANGLIA ASSOCIATED WITH
FACIALNERVE-
• Geniculate ganglion
• Submandibular ganglion
• Pterygopalatine ganglion

20. SubmandibularGanglion
-The submandibular ganglion is small and fusiform
in shape
-It is situated above the deep portion of the
submandibular gland, on the hyoglossus muscle,
near the posterior border of the mylohyoid muscle.
- The ganglion 'hangs' by two nerve filaments from
the lower border of the lingual nerve (itself a branch
of the mandibular nerve, CN V3). It is suspended
from the lingual nerve by two filaments, one
anterior and one posterior. Through the posterior of
these it receives a branch from the chorda tympani
nerve which runs in the sheath of the lingual nerve.

21. PterygopalatineGanglion-
• The pterygopalatine ganglion (meckel's ganglion, nasal ganglion or
sphenopalatine ganglion) is a parasympathetic ganglion found in the
pterygopalatine fossa.
• It's largely innervated by the greater petrosal nerve (a branch of the
facial nerve); and its axons project to the lacrimal glands and nasal
mucosa

22. CLINICAL EXAMINATION
- Inspection-
- Facial asymmetry, nasolabial fold with forehead wrinkles, movements
during spontaneous facial expression • Tone of the muscles of facial
expression, • Atrophy and fasciculations • Abnormal muscle contractions
and involuntary movements• Spontaneous blinking for frequency and
symmetry.

23. (A) Testing of Facial nerve(motor system)
Testing the temporal branches of the facial nerve – patient is asked
to frown and wrinkle his or her forehead.
Testing the Zygomatic branches of the facial nerve- patient is asked
to close their eyes tightly
Testing the buccal branches of the facial nerve
• Puff up cheeks (buccinator)
• Smile and show teeth (orbicularis oris)
• Tap with finger over each cheek to detect ease of air expulsion
on the affected side

25. (B)Examination of Reflexes
• Corneal Reflex • Afferent limb of the reflex is mediated by CN V1,
the efferent limb by CN VII.

26. Stapedius reflex-
• Nerve to stapedius muscle test
• Impedence audiometry can record the
presence or absence of stapedius muscle
contraction to sound stimuli 70 to 100 db
above hearing threshold
• Absence reflex or a reflex less than half the
amplitude is due to a lesion proximal to
stapedius nerve.

27. (c)Examination of
Sensory Functions-
-Hypesthesia of posterior wall of the external auditory
meatus in proximal facial nerve lesions.
-Taste on anterior two-thirds of the tongue-use four
substances for testing:
• Sucrose (sweet), sodium chloride (salty), quinine
(bitter), and citric acid (sour).
• Patient with a peripheral pattern of facial weakness has
impaired taste, the lesion is proximal to the junction with
the chorda tympani.

28. (D)Examinationof
secretoryfunction-
• Examination ofSecretory Functions
• Tear productionmay be quantitated
with the Schirmer test.
• Lacrimalreflex istearing, usually
bilateral, caused by stimulatingthe
cornea.
• Nasolacrimalreflex iselicited by
mechanicalstimulation ofthe nasal
mucosa, or by chemicalstimulation
usingirritatingsubstancessuch as
ammonia.
• Abnormalitiesofsalivation are
usually suggested by the history.

29. • • TOPOGNOSTIC TESTING- tear-hear-taste-face
• 1. Schirmer test for lacrimation (GSPN)
• 2. Stapedial reflex test (Stapedial branch) 3.
• 3.Taste testing (Chorda tympani nerve)
• 4. Salivary flow rates & pH (Chorda tympani)
• • ELECTROPHYSIOLOGIC TESTS
• 1. Nerve stimulation test (NST)
• 2. Electromyography(EMG)
• 3. Maximal stimulation test (MST)

30. Facial weakness-
• Two types of neurogenic facial nerve
weakness:
• Peripheralor lower motor neuron -
result from a lesion anywhere from the CN
VII nucleus in the pons to the terminal
branches in the face.
• Central facial palsy (CFP)orupper
motor neuron - due to a lesion involving
the supranuclear pathways before they
synapse on the facial nucleus.

31. Peripheral Facial Palsy-
• There is flaccid weakness of all the muscles of facial expression on
the involved side, both upper and lower face, and the paralysis is
usually complete

32. Cont..
• Palpebral fissure is open wider than normal, and there may
be inability to close the eye (lagophthalmos).
• Very mild PFP may produce only slower and less complete
blink on the involved side.
• Bell’s phenomenon- Attempting to close involved eye
causes a reflex upturning of the eyeball
• Levator sign of Dutemps and Céstan- Patient look down,
then close the eyes slowly; because the function of levator
palpebrae superioris is no longer counteracted by orbicularis
oculi, upper lid on the paralyzed side moves upward slightly.

33. • Negro’s sign- eyeball on the paralyzed side deviates
outward and elevates more than the normal one when
the patient raises her eyes.
• Bergara-Wartenberg sign- loss of the fine vibrations
palpable with the thumbs or fingertips resting lightly
on the lids as the patient tries to close the eyes as
tightly as possible.
• Platysma sign of Babinski- asymmetric
contraction of the platysma, less on the
involved side, when the mouth is opened

34. House-Brackmann grading system
Grade I – Normal
Grade II - Mild dysfunction, slight weakness on close inspection,
normal symmetry at rest
Grade III - Moderate dysfunction, obvious but not disfiguring
difference between sides, eye can be completely closed with effort
Grade IV - Moderately severe, normal tone at rest, obvious weakness
or asymmetry with movement, incomplete closure of eye
Grade V - Severe dysfunction, only barely perceptible motion,
asymmetry at rest
Grade VI - No movement

35. Bell’s Palsy
• Most common form of lower motor neuron facial palsy.
• Incidence is 23/1,00,000
• 1 in 6o life time occurrence of single episode
• Affects men and women equally , all ages ,all times of the year.
• Increased occurrence in the elderly diabetics, hypertensives than in
the common people.
• Increased incidence in women during the third trimester of
pregnancy 2 weeks preceding delivery ,first two weeks postpartum.

36. Etiology:
• Idiopathic
• Herpes simplex virus 1
• Herpes zoster is probably second most common viral infection
associated with PFP.
• Other viruses implicated include cytomegalovirus, Epstein-Barr
virus, human herpes virus 6, and coxsackie.
• Inactivated intra nasal influenza vaccine

37. Clinical features-
• Onset of bell’s palsy is acute.
• ½ of the cases attainmaximumparalysisin 48 hours.
• All cases are clinicallyprominent by 5 days.
• Pain behind the ear may precede the paralysis by a day or two .
• Impairement of taste is present to some degree in all cases– rarely
beyond second week of paralysis.
• Hyperacusis or distortionof sound in ipsilateralear ---paralysis of
stapedius muscle.
• Paralysis is partialin 30%,complete in 70%cases.
• About 1% of cases are bilateral

38. • Enhancement of the facial nerve on gadolinium enhanced MRI
. Increased lymphocytes ,mononuclear cells in CSF.
Prognosis
• 80% patients recover within a few weeks.2-12 weeks
• 10%--permanent long term sequelae
.• 8%--recurrence

39. Treatment-
• Symptomatic
• Protection of eye during the sleep patch
• Massage of the weakened muscles
• Lubricating eye drops
• Prednisolone60-80 mg/day in divided doses intial4-5 days,thentaper
over next 7-10 days.
• Acyclovir alone is not useful.
• Acyclovir 400mg 5 times a day –10 days
• Valacyclovir 1000mg /day 5-7 days.
• No evidence that surgicaldecompressionof facial nerve is effective ---
may be harmful.

40. Facial Weaknessof Central Origin
• Weakness of the lower face, with relative sparing
of upper face
• Upper face is not necessarily completely spared,
but it is always involved to a lesser degree than the
lower face.
• Lesion involving the corticobulbar fibers
anywhere prior to their synapse on the facial nerve
nucleus will cause a CFP
• Lesions are most often in the cortex or internal
capsule.

41. • • There are two variations of CFP:
• (a) Volitional, or voluntary- weakness more marked on voluntary
contraction, when patient is asked to smile or bare her teeth.
• Result from a lesion involving either the cortical center in the
lower third of the pre-central gyrus that controls facial movements,
or the corticobulbar tract.
(b) Emotional, or mimetic –Facial asymmetry more apparent with
spontaneous expression, as when laughing.
• Most commonly results from thalamic or striatocapsular lesions,
usually infarction, rarely with brainstem lesions

42. Difference bw UMN &LMN Facial palsy-

45. Syndromes associated with facial nerve.
• Crocodile tear syndrome - involves lacrimation or tearing
whenever the patient is eating or drinking.
Freys syndrome- complication of surgery or an injury of the
salivary (parotid) gland in the cheek.
• Symptoms include sweating and flushing on the cheek,
temple or near the ear, particularly when eating foods

46. Ramsay Hunt syndrome-
• A special form of Herpes zoster
infection of the Geniculate ganglion
with the involvment of the external ear
and the oral mucosa.
Triad-
1.Ipsilatral facial paralysis
2.Ear pain
3.vesciles in ear canal and auricle

47. Melkersson Rosenthal syndrome
• Recurrent attacks of facial paralysis
• Associated with multiple episodes of non-
pitting, non-inflammatory painless edema of
the face
• Chelitis granulomatosa
• Fissured tongue

48. MOBIUS SYNDROME
• Möbius’ syndrome (congenital oculofacial paralysis) is the association
of congenital facial nerve palsy with paralysis of the extraocular
muscles, especially the lateral rectus due to hypoplasia or aplasia of
the CN nuclei .

49. • Millard-Gubler syndrome –
• ipsilateral facial peralysis
• contralateral hemiparesis
• Foville syndrome
• ipsilateral facial peralysis and
• horizontal gaze palsy with
• contralateral hemiparesis

50. •THANK YOU

51. • REFERENCES • DeJong’s The Neurological examination, 7th edition
• Grays Anatomy : 39th Edition • UptoDate. Com