The document provides details on the anatomy and clinical examination of the facial nerve (CNVII). It discusses the supranuclear, nuclear/intra-axial, and peripheral components of the facial nerve. Key points include that CNVII has four nuclei in the lower pons and exits the brainstem in two roots. It describes the intra- and extra-axial course of the nerve through the internal auditory canal, facial canal, and branches after exiting the stylomastoid foramen. Clinical tests for assessing motor, sensory, and parasympathetic function are outlined. Localization of lesions is discussed in relation to upper and lower motor neuron palsies.

1. Facial nerve
Apooorv Pandey.

2. Content
 Introduction
 Anatomy
 Clinical Examination
 Applied aspect

3. Facial nerve
 Seventh CN- mixed nerve.
 Nerve of second brachial arch
 Nerve of facial expression.

4.  The facial nerve (CNVII) – motor + sensory
 Parasympathetic secretory fibers
submandibular, sublingual salivary glands
lacrimal gland
mucous membranes of Oral and nasal cavities.
 Sensory functions:
Taste
sensation (eardrum and external auditory canal)
sensation: the muscles it supplies

5. InfranuclearNuclear
Four
components
Supranuclear
Pyramidal and
extrapyramidal
ANATOMY

6. SUPRANUCLEAR ANATOMY
 Has specific areas on the cerebral
cortex.
 Facial pyramidal fibers begin
 It is represented according to the part
it supplies on the face.

7. Path of voluntary facial expressions
(Pyramidal)
 Contralateral precentral gyrus are carried
through corticobulbar tract (pyramidal)
Internal Capsule
Midbrain
Cross over to the opposite side
Motor Facial nerve nucleus in Pons.
DeJong's The Neurologic Examination, 6th Edition

8. Facial Nerve has 4 nuclei (lower pons)
1. Motor nucleus
2. Sup salivolacrimatory nucleus (parasympathetic)
3. Nucleus of tractus solitarius (gustatory)
4. Spinal tract nucleus (sensory)
Nuclear / Intra-axial Anatomy
DeJong's The Neurologic Examination, 6th Edition

9. Motor nucleus fibres
Ventrolateral pontine tegmentum
Floor of fourth ventricle forming
facial colliculus
Fibers then course anterolaterally to exit lateral
brainstem at pontomedullary junction

10. Sup salivolacrimatory nucleus (parasympathetic)
Nucleus of tractus solitarius (gustatory)
Spinal tract nucleus (sensory)
NERVOUS INTERMEDIUS
DeJong's The Neurologic Examination, 6th Edition

12.  The facial nerve leaves the brainstem in two roots
MOTOR ROOT (70%)
NERVOUS INTERMEDIUS (30%)

13. Extra-axial course
Emerge from lateral brainstem at
root exit zone on pontomedullary
junction just caudal to the roots of
CN V
Cerebellopontine angle (CPA) cistern
DeJong's The Neurologic Examination, 6th Edition

14. Cisternal segment
Has 2 roots at the exit
Larger motor root anteriorly
Smaller sensory nervus
intermedius posteriorly
CN8 exits brainstem posterior to CNVII
These nerves resemble the nerve roots of the spinal cord in
that
they are devoid of epineurium but covered in piamater and
bathed in cerebrospinal fluid.Diagnostic and imaging anatomyHarnsberger

15.  Intrapetrous course of the facial nerve has two portions:
(a) in the internal auditory canal
(b) in the facial canal or Fallopean aqueduct
 The internal auditory segment is 7 to 8 mm in length

16.  At the entrance to the internal
auditory canal (IAC)
 The facial nerve at this point lies in
close proximity to the anterior
inferior cerebellar artery (AICA)

18.  In its course through the facial canal the nerve has four
segments:
1) Labyrinthine
II) Horizontal or tympanic
III) Pyramidal
IV) Mastoid
Bell’s Palsy: Diagnosis and Management JEFFREY D. TIEMSTRA, MD, and NANDINI
KHATKHATE, MD University of Illinois at Chicago College of Medicine, Chicago, Illinois

19. The labyrinthine segment
lies laterally between the
cochlea and vestibule,
toward the medial wall of
the tympanic cavity
It extends from the internal auditory canal to the geniculate
ganglion. (3–5 mm)

20.  The nerve turns abruptly
and runs horizontally for
about 1 cm (horizontal or
tympanic segment)
 Turns backward and arches
downward behind the
tympanic cavity.
 Extends from the geniculate
ganglion to the second turn
of the facial nerve External genu & geniculate ganglion

21.  The tympanic nerve segment is covered by a thin bony sheath.

22.  The pyramidal segment joins the horizontal and
mastoid segments, and gives off the branch to the
stapedius muscle.
 The mastoid segment (13–15 mm)
extends from this point to the
stylomastoid foramen.

24. In the adult, it is protected
laterally by the mastoid tip,
tympanic ring and mandibular
ramus.
Whereas in children younger
than 2 years it is relatively
superficial.
Postauricular incisions in this younger population must be
carefully planned because the trunk of the facial nerve is a
subcutaneous structure at this level.

25. Pesanserinus

26. Sensory
Greater sup. petrosal nerve
Chorda tympani
Motor
Nerve to stapedius
Posterior auricular
Nerve to Diagastric
Nerve to stylohyoid
Muscles of facial expression
Branches

28.  After exiting the stylomastoid foramen, the facial nerve gives
off branches to
The posterior auricular
The posterior belly of digastric
The stylohyoid

29. Post auricular branch
 Ascends btw EAM and mastoid
 Divides into auricular and occipital branches
Digastric branch
 Posterior belly of digastric
Stylohyoid branch
 Stylohyoid muscle

30. Final Innervation
Innervates the muscles of facial expression.

31. General Somatic Efferents

32. Parasympathetic fibres

33.  Temporal bone
via the petrosal foramen
 Enters middle cranial fossa
via the foramen lacerum
 And reaches the base of medial pterygoid plate
 Meet sympathetic fibers of deep petrosal nerve.
 The parasympathetic and sympathetic fibers together make up the
nerve of the pterygoid canal
Greater Superficial Petrosal Nerve

34.  Upon exiting the pterygoid canal, pre-ganglionic
parasympathetic fibers of CNVII synapse in the
pterygopalatine ganglion
(which is suspended from the fibers of the maxillary division of
the trigeminal nerve (V2) in the pterygopalatine fossa.)

35.  Post-ganglionic parasympathetic
the lacrimal gland (via the lacrimal nerve)
mucous membranes of the nasal and oral pharynx

36. Special Visceral Afferents or Sensations

37. Corda Tympani Course
The fibers pass through the middle ear in close
relationship with the tympanic membrane and exit
the base of the skull to enter the inferotemporal
fossa.

38.  In the inferotemporal fossa the
chorda tympani joins the lingual
branch of the mandibular division
of CNV (V3).
 Pre-ganglionic fibers synapse in
the submandibular ganglion
 Post-ganglionic fibers then enter
the submandibular gland

39. General Somatic Afferents

40. Applied aspect

41. (1829):THE DISCOVERY
OFTHE NERVE OF
FACIAL EXPRESSION
 Sir Charles Bell (1829)
 3 cases of facial paralysis due
to facial nerve trauma.

42. Causes of nerve palsy

43. Clinical Examination of the facial nerve
Motor
 Frontalis,
 Corrugator Supercilii
 Orbicularis oculi
 Buccinator
 Orbicularis Oris
 Platysma

45. Sensory
 Evaluation of taste on the anterior two-thirds of the
tongue.
 Four fundamental tastes (sweet, sour, salty and bitter)
and asymmetries documented.

46. Reflex and Parasympathetic Function
Corneal Reflex Lacrimation
Salivation

47. Other important tests
1. Schirmer's Tear test
2. Nerve conduction and Potential Studies
3. CT / MRI

48.  Inflammatory facial nerve lesions can be
demonstrated by MRI after gadolinium contrast
administration.
 Otogenic and traumatic facial paralysis should always
be evaluated by thin-slice bone-window CT scanning
of the temporal bone.

49. Testing facial nerve function
 90% of nerve disorder occurs along the nerves intra temporal
course
 Electro diagnosis – testing degree of distal axonal degeneration
 Topognosis – testing function of accessory branches

50. Facial nerve tests:
 Topognosis - lacrimation, stapedial reflex, salivary
flow, taste
 CT- to rule out trauma to the nerve
 Prognosis – Electromyography (EMG)
Electrical Nuro Graphy (ENoG)
 Diagnostic – Blink reflex, EMG, ENoG

51. Electro diagnostic testing
 EMG-electromyography
 Is a electro physiologic test
 It measures electrical response
1. During needle insertion
2. At rest
3. During volitional movement

52. Nerve conduction time:
 Nerve stimulated near the foramen and record one of
the facial muscle group
 Latency for each action potential is defined as the time
between onset of stimulus and onset of response

55. Cortical innervation of
left face
Upper half: BiLateral
Lower Half: Predominantly
contralateral
Left

56. Lower Motor Neuron (LMN) Lesion

57. Clinical Examination

58. Upper Motor Neuron (UMN) Palsy

59. Facial Paralysis
UPPER MOTOR NEURON LOWER MOTOR NEURON
Lesions is above the pons. Lesions is in the pons or in the
pathway from pons to its exit.
Patient can make furrows on looking
upwards
Furrows are absent on looking
upwards of the affected side of
face.
Lower part of the face is involved on
the opposite side of the lesion.
The whole face and forehead
involved on the same side of the
lesion.
Isolated involment of this type is
rare.
Isolated involment of this type is
common.
It is invariably associated with
hemiplegia .
It may be associated with
hemiplegia .

60. GRADING
Dr John W. House and Dr Derald E. Brackmann,
otolaryngologists in Los Angeles, who first described the
system in 1985.
Vrabec JT, Backous DD, Djalilian HR, et al. (April 2009). "Facial Nerve Grading
System 2.0". Otolaryngol Head Neck Surg

62. Localization of Lesions Affecting Cranial
Nerve VII
 Supranuclear Lesions (Central Facial Palsy)
 Nuclear and Fascicular Lesions (Pontine Lesions)
 Peripheral Facial Nerve Palsy

63. Nuclear Lesions
 May affect either the nucleus of the facial nerve or its intrapontine axons
Ipsilateral Facial palsy with
Abducens fascicle or nucleus
Paramedian Pontine Reticular Formation
(PPRF)
(paralysis of conjugate gaze to the psilateral side)
Corticospinal tract (contralateral hemiplegia)

64. Abducens fascicle or nucleus

65. PERIPHERAL LESIONS

66. Lower motor lesion of Facial nerve
• Palsy +loss of taste sensation – in the canal
• Palsy +loss of taste +hyperacusis – just after entrance
into the canal
• All the above + loss of hearing – at the internal
auditory meatus
• All the above + lateral rectus damage – cerebo
potine angle involvement Bell’s palsy.

67. Millard-Gubler Syndrome
Lesion located in the ventral pons that destroys the fascicles of the facial and
abducens nerves and the corticospinal tract
Ipsilateral peripheral-type facial paralysis
Ipsilateral lateral rectus paralysis
(diplopia with failure to abduct
the ipsilateral eye)
Contralateral hemiplegia

68. Foville Syndrome
 Lesion located in the pontine tegmentum that
destroys the fascicle of the facial nerve, the PPRF,
and the corticospinal tract.
 Ipsilateral peripheral-type facial paralysis
 Paralysis of conjugate gaze to the side
 of the lesion
 Contralateral hemiplegia

69. Möbius syndrome
 Möbius syndrome results from the
underdevelopment of the VI and
VII cranial nerves.
 Loss of facial expressions and
horizontal gaze.

70. EXTRAPYRAMIDAL SYSTEM
 Consist of basal ganglia and the descending motor projections
other than the fibers of the pyramid or cortico-bulbar tracts.
 Extrapyramidal system, involves diffuse axonal connections
between multiple regions including the basal ganglia,
hypothalamus, and motor cortex.
 The extrapyramidal system is capable of producing
involuntary facial movements (absence of major pyramidal
pathways)

71.  A dissociation between voluntary facial movements
(volitional facial palsy) and emotional facial movements
(emotional or mimetic facial palsy)

72. Important points during Embryonic Development
• 7th
cranial nerve is first identifiable at the end of 3rd
week
• Important steps in facial nerve development occurs
throughout gestation and the nerve is not fully developed
until appx 4yrs after birth.
• Because the cell collection also gives rise
to the 8th
cranial (acoustic) nerve, it is
referred to as the facioacoustic
cranial primordium or crest.

73.  During its development the facial andVestibulochochlear
nerve are not distinguishable till the 37th
day of the
embryonic life.
 The facial nerve is the nerve of the second branchial arch
and its branch, chorda tympanic develops as the nerve to
the first branchial arch during the early embryonic
period.
 6th
an 7th
cranial nerve motor nuclei lie in close approximation
Congenital Mobius syndrome
Acquired inflammatory /vascular / neoplastic

74. THANK YOU