The facial nerve is the seventh cranial nerve, or simply CN VII. It emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue.
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Facial Nerve
1. FACIAL NERVE
Guided by
Dr Anil Govindrao Ghom
Dr Ajit Mishra
Dr. Shweta Singh
Dr. Savita Ghom
Presented By
Dr. Bratati Dey
(PG 1ST YEAR) OMR
2. CONTENTSCONTENTS
• Introduction
• Functional components
• Origin
• Course and relations
• Branches and distribution
• Ganglia
• Clinical anatomy
– Upper motor neuron paralysis
– Lower motor neuron paralysis (Bells’s palsy)
– Clinical testing of the nerve
– Facial nerve paralysis in newborn
– Crocodile tears Syndrome
– Ramsay-Hunt Syndrome
3. INTRODUCTIONINTRODUCTION
• It is VII cranial nerve.
• It is a mixed nerve having both motor and sensory component.
It is a branch of second brancheal arch.
• Has two root sensory and motor, sensory root known as
Nervous Intermedius
4. FUNCTIONAL COMPONENTFUNCTIONAL COMPONENT
1. Special visceral or branchial
efferent,
2. General visceral efferent or
parasympathetic
3. General visceral afferent
component
4. Special visceral afferent fibers
5. General somatic afferent fibers
7. AREA OF SUPPLYAREA OF SUPPLY
1. Muscle of the face, scalp,
auricle, buccinator,
stylohyoid, platysma,
stapidius, posterior belly of
digastric, motor area of
facial nerve.
2. Secretomotor supply to
submandibular and
sublingual salivary gland
3. Sensory component bring
taste sensation from anterior
2/3 of tongue except
circumvallate papillae.
8. ORIGINORIGIN
1. Motor nucleus gives rise to motor
component of facial nerves in the
pons
2. Superior salivatory nucleus gives
rise to secretomotor component of
facial nerve in the pons.
3. Nucleus of tractus solitarious
gives rise to sensory component
of facial nerve in the medulla
oblongata.
10. COURSECOURSE
It arises from Pons and passes
laterally to leave the cranial cavity
by entering the internal auditory
meatus. (along with VIII cranial
nerve sensory root lies between
motor root and VIII nerve) in close
relation to tympanic membrane
It enters the facial canal which is
directed laterally in the inner ear then
backward downward in the middle
ear
Finally it leaves the via stylomastoid
foramen
11. Outside the skull the facial nerve passes along the styloid
process to enter the posterio-medial surface of parotid gland.
Passes transversely superficial to retro-mandibular vein &
external carotid artery.
Termination- It enters inside the parotid gland by dividing into
5 terminal branches.
13. BRANCHES AND DISTRIBUTIONBRANCHES AND DISTRIBUTION
A. Intra-cranial-
Greater-petrosal nerve,
Nerve to stapedius,
Chorda tympani nerve
B. At its exit from stylomastoid foramen-
Posterior auricular
Digastric
Stylohyoid
C. Terminal branches within the parotid gland-
Temporal
Zygomatic
Buccal
Marginal mandibular
Cervical
D. Communicating branches With adjacent cranial and spinal nerves.
14. GreaterGreater petrosalpetrosal nervenerve
• Greater petrosal nerve originates at the geniculate ganglion
• Run through pterigoid canal and carry preganglionic
parasympathetic fiber to the sphenopalatine ganglion
• Post ganglionic fiber start from sphenopalatine ganglion and
supply the lacrimal gland.
16. Nerve toNerve to stapediusstapedius
It arises opposite the pyramid of middle ear, & supplies the
stapedius muscle
The muscle damps excessive vibrations of the stapes caused
by high-pitched sounds.
Applied anatomy-
In paralysis of the muscle, even normal sounds appear too
loud & is known as HyperacusisHyperacusis.
17. ChordaChorda tympani nervetympani nerve
Arises in the vertical part of the facial canal about 6cm above
the stylomastoid foramen
It runs upwards and forwards in a bony canal &
It enters the middle ear and runs forwards in close relation to
the tympanic membrane.
Then it leave middle ear cavity by passing through
pterigopalatine fissure to enters in the infra temporal fossa
Where it joint the lingual nerve deep to muscle and
distribution with it.
18. It carries-
Preganglionic secretomotor fibers to the submandibular
ganglion for supply of sub mandibular & sublingual salivary
glands.
Taste fibers from the anterior 2/3 of the tongue except
circumvallate papillae.
19. Posterior auricular nervePosterior auricular nerve
• This nerve arises just below the stylomastoid foramen
• It ascends between the mastoid process & the external acqustic
meatus
• Area of supply-
– Auricularis posterior
– Occipitalis
– Intrinsic muscles on the back of auricle
22. Temporal branchTemporal branch
It crosses the zygomatic arch and supply
Auricularis anterior
Auricularis superior
Intrinsic muscle on the lateral side of the ear
Frontalis
Orbicularis oculi
Corrugator supercilii
24. BuccalBuccal branchbranch
Buccal branches are two in number
The upper buccal branch run above the parotid
duct and the lower buccal branch run below the
duct
They supply muscles in that vicinity especially the
buccinator.
25. MarginalMarginal mandibularmandibular branchbranch
• Marginal mandibular branch run below the angle of mandible
deep to the platysma.
• It crosses the body of mandible and supplies muscle of the
lower lip and chin.
26. Cervical branchCervical branch
• It emerges from the apex of the parotid gland, & run
downwards & forwards in the neck to supply the platysma.
27. Communicating branchesCommunicating branches
• For effective co-ordination between the movement of the
muscles of the first second and third branchial arches, the
motor nerves of the three arches communicate with each other
• The facial nerve also communicate with the sensory nerves
distributed over its motor territory.
28. GangliaGanglia
The ganglia associated with the facial nerve are as follows.
1. The Geniculate ganglion-it is a sensory ganglion. The
taste fibres present in the nerve are perepheral processes
of pseudounipolar neurons present in the geniculte
ganglion.
2. The Submandibular ganglion- it is a parasympathetic
ganglion, for relay of secretomotor fobre to the
submandibular and sublingual gland.
3. The Pterigopalatine ganglion- is also a parasympathetic
ganglion. Secretomotor fibers meant for the lacrimal
gland relay in this ganglion.
30. CLINICAL ANATOMYCLINICAL ANATOMY
Facial palsy
lower motor
neuron type
Bells’s palsy
and loss
of taste sensation
Bells’s and loss
of taste sensation
hyperausis
Upper motor
neuron type
Paralysis of
lower half of face
Paralysis of
contralateral
lower half of face
32. Facial palsyFacial palsy
UPPERUPPER MOTORMOTOR NEURONNEURON PARALYSISPARALYSIS of VII nerve results
in paralysis of contralateral lower quadrant of face only.
• It is seldom isolated palsy.
• Affect mainly the muscles of lower part of face & is never
complete.
• The emotional movement are preserved.
• No muscle contraction.
• No reaction of regeneration.
• Electromyography and nerve conduction is normal.
33. LOWERLOWER MOTORMOTOR NEURONNEURON PALSY/BELL’SPALSY/BELL’S PALSYPALSY -
It is also called 7th nerve paraplegia or idiopathic facial paralysis.
Etiology-
Cold
Trauma (after extraction, injection of local anaesthesia)
Surgical procedure (such as removal of parotid gland tumor)
Ischemia
Facial canal & middle ear neoplasm
Tumors
Other causes (multiple sclerosis)
34. Sign & symptomSign & symptom
Ear ache
Hearing loss
Pain or paraesthesia
Any abnormality on otoscopy—including otitis media
Associated cranial neuropathies or other neurological
signs
35. Hypertension
Lymphadenopathy
pallor or bruising
Vesicles in external meatus or on soft palate
Single branch involvement
Gradual progression of paralysis beyond 3 weeks Recurrence
Mastoid swelling
36. Clinical features-
Age & sex: women> men, middle age group.
Onset: it begins abruptly as paralysis of facial musculature
Prodromal symptoms: unilateral pain on ear temple &
mastoid area or at the angle of jaw.
Symptoms: speaking and eating difficulty, occasionally loss
of taste sensation on ant. 2/3 of tongue.
Eyes: Eyes can’t be closed and wrinkles disappear,
watering of eye.
37. Mask like face.
Angle of mouth drops down.
Face become asymmetrical.
Saliva drool from corner of mouth.
Syndrome associated with
melkerson-rosenthal syndrome.
Lip &facial
swelling
VII nerve palsy
Intermittent
VII nerve palsy
Fissure tongue
39. Diagnosis-
clinical diagnosis: Slurred speech, mask like face, drooling
of saliva can diagnose this condition.
lesion above origin of chorda tympani nerve show symptoms
of bells palsy plus loss of taste sensation from anterior 2/3 of
tongue except circumvallate papilae.
40. • Facial nerve can be injured at any level during its course
• Lower motor neuron paralysis of VII nerve cause paralysis of
ipsilateral half face i.e both upper quadrant & lower quadrant
of same side as the injury.
41. •• ManagementManagement--
Vasodialator: like histamine
Surgical decompression & anastomosis of nerve
Nicotinic acid
Others- systemic steroid or ACTH inj.
vitamin B12, alone or in combination with
steroids, recovered faster than those treated with
steroids alone
100% hyperbaric oxygen recovered faster than
those treated with steroids
42. Indication For Different Type Of SurgeryIndication For Different Type Of Surgery
Early immediate nerve repair, in case of injury to the nerve
Late nerve crossing by suturing perepheral branches of facial
nerve to one of the following nerves
Hypoglossal nerve, spinal accessory nerve
Phrenic nerve
Surgery to achieve movement in long standing facial palsy
43. •• StaticStatic procedureprocedure--
suspension of lips cheeks & angle of mouth to zygomatic
bone or temporal fascia using fascia lata, palmaris longus
tendon or other alloplastic material.
Medial canthoplasty to reduce epiphora.
Lateral tarsorrhaphy to prevent exposure keratitis due to
widened palpebral fissure
44. •• DynamicDynamic procedureprocedure--
Muscle transfer with carefully preserved muscle nerve &
vessel (temporalis muscle transfer, masseter muscle muscle
transfer).
Cross face nerve transplantation using sural nerve using
microscope (sural nerve is sutured to the 2-3 relatively in
significant branches to the VII nerve)
Free neurovascular gracilis muscle graft using
microvascular technique.
45. Clinical testing of the nerveClinical testing of the nerve
• The facial nerve is examined by testing the following the facial
muscle
A. Frontalis- ask the patient to look upwards without moving his head,
and look for the normal horizontal wrinkles of the forehead
B. Dilators of mouth- showing the teeth
C. Orbicularis oculi- tight closure of the eyes
D. Buccinator- puffing the mouth & then blowing forcibly as is in
whistling
46. • Platysma-
– forcible pulling the angle of the mouth downwards
& backwards forming prominent vertical fold of
skin on the side of the neck.
– The platysma contracts along with the risorius.
48. • In the infra-nuclear lesions of the facial nerve, known as bells
palsy, the whole of the face of the same side gets paralysed
– Asymmetrical face,
– affected side become motionless,
– eye can’t be closed
– Any attempt to the smile drawn the mouth to the normal side
– During mastication food accumulates between the cheek and teeth
49. • In the supra-nuclear lesions of the facial nerve
usually a part of hemiplegia, only lower part of the
opposite side of face is paralysed.
• The upper part with the frontalis & orbicularis oculi
escape due to its bilateral representation in the
cerebral cortex.
50. Facial nerve paralysis in newbornFacial nerve paralysis in newborn
• The mastoid process is absent in newborn & stylomastoid
foramen is superficial.
• Manipulation of baby’s head during delivery may damage the
VII nerve.
• This leads paralysis of facial muscles (buccinator) required for
sucking the milk.
51. Crocodile tears syndromeCrocodile tears syndrome
• Lacrimation during eating occurs
due to aberrant regeneration after
trauma.
• In case of damage to facial nerve
proximal to geniculate ganglia,
regenerating fibre for sub
mandibular salivary gland grow in
endo neural sheaths of
preganglionic secretomotor fibres
supplying the lacrimal gland.
• management- injection of
botulinum toxin.
52. RamsayRamsay--Hunt syndromeHunt syndrome
• Involvement of geniculate ganglia by herpes zoster result in
this syndrome
• It shows following syndrome
Hyperacusis
Loss of lacrimation
Loss of sensation of taste in anterior two-third of tongue
except vallate papillae (supplier by afferent IX cranial
nerve)
Bells’s palsy and lack of salivation
Vesicles on the auricle.
53. INVESTIGATIONSINVESTIGATIONS
Otoscopy is mandatory in all patients presenting with facial
paralysis
Where adequate auditory acuity cannot be confirmed an audiogram
should be arranged.
Hematological investigation- Complete blood count
Radiological investigation-
MRI (to identify brain stem pathology)
High contrast CT
Contrast enhanced magnetic resonance imaging
Neurophysiological studies-
measurement of fibrillation potential (part of electromyography)
recording of the blink reflex
54. CONCLUSIONCONCLUSION
• To date there is no clear evidence that any form of treatment
improves outcome of idiopathic facial palsy in children.
• Ninety five per cent of children will recover full function,
• most within the first three weeks of the illness.
• Protection of the cornea, with artificial tears and overnight
patching, is normally all that is required
• Neurophysiological assessment is helpful in patients with
weakness persisting beyond three weeks.
55. REFERENCESREFERENCES
BD Chaurasia’s human anatomy 354-358
Anand’s human anatomy for dental students
Anil govindrao ghom, text book of oral medicine 760,1027
K rajgopal shenoy Manipal manual of surgery 307
Inamura H, Aoyagi M, Tojima H, et al. Facial nerve palsy in
children: clinical aspects of diagnosis and treatment. Acta
Otolaryngol Suppl 1994;511:150–2.
Investigation and treatment of facial paralysis Accident and
Emergency Department, Birmingham Children’s Hospital,
Steelhouse Lane, Birmingham B4 6NH, UK