The seventh cranial nerve is an extremely important entity to dental professionals..... specially if we want to see that pretty smile on our patients face after we are done with the treatment. hence this was an effort to make a seminar on facial nerve. hope it helps you!!!

1. 1 22-Sep-16

2. Nikita Burde
1st MDS
THE FACIAL NERVE
22-Sep-162

3. INTRODUCTION
FUNCTIONAL COMPONENTS
NUCLEI
THE FACIAL NUCLEUS
INTRACRANIAL COURSE
ROOTS
COURSE AND RELATIONS
COMMUNICATING BRANCHES
BRANCHES OF DISTRIBUTION
APPLIED ANATOMY
REFERENCES3 22-Sep-16

4. 4 22-Sep-16

5. 5
Special Visceral
efferent
(Branchial
efferent)
General Visceral
efferent
(Parasympathetic)
General Visceral
afferent
Special Visceral
afferent
General somatic
afferent
22-Sep-16

6. 6 22-Sep-16

7. 7 BRANCHIAL EFFERENT 22-Sep-16

8. 8
GENERAL VISCERAL EFFERENT
PARASYMPATHETIC
(SECRETOMOTOR) 22-Sep-16

9. 9
SPECIAL VISCERAL AFFERE
22-Sep-16

10. 10
GENERAL SOMATIC AFFERENT22-Sep-16

11. 11
NUCLEI
MOTOR
(BRANCHIOM
OTOR)
LACRIMATO
RY
(PARASYMP
ATHETIC)
SUPERIOR
SALIVATORY
(PARASYMPA
THETIC)
TRACTUS
SOLITARIUS
(GUSTATORY
)
22-Sep-16

12. THE FACIAL NUCLEUS
12
 Lies deep in the pontine
reticular formation
 Receives both crossed
corticonuclear fibers and
smaller ipsilateral number and
ipsilateral rubroreticular
 Axons of large motor neurons
form facial nerve
 At first they incline
dorsomedially towards the
fourth ventricle below the
abducent nucleus and
ascending medial to it near the
medial longitudinal fasciculus
through which the facial nerve
may communicate with other
cranial nerves
 Fibers now curve
anterolaterally round the upper
pole of abducent nucleus
GENICULUM OF FACIAL
NERVE 22-Sep-16

13. 13
 1) Motor root 2) Sensory root
NERVUS INTERMEDIUS
 The course of the facial nerve can be divided into six
segments
a. Intracranial segment
b. Meatal segment (Brainstem to internal acoustic
meatus)
c. Labyrinthine segment (Internal acoustic meatus to
geniculate ganglion)
d. Tympanic segment (geniculate ganglion to
pyramidal eminence)
e. Mastoid segment (pyramidal eminence to
stylomastoid foramen)
f. Extracranial or extratemporal segment (stylomastoid
Within
the ear
22-Sep-16

14. 14 22-Sep-16

15. 15
 The two roots emerge at the
CAUDAL border of the PONS
lateral to the INFERIOR OLIVE
and INFERIOR CEREBELLAR
PEDUNCLE.
 Nervus Intermedius or nerve
of Wrisberg which lies
between the motor root and
vestibulocochlear nerve, hence
the name, contains sensory
and parasympathetic fibers of
facial nerve.
INTRACRANIAL COURSE
22-Sep-16

16. 16
The nervus intermedius usually
cleaves at first to the vestibulocochlear
nerve rather than the facial nerve,
passing to the facial nerve as it
approaches the internal acoustic
meatus.
22-Sep-16

17. 17
NERVUS INTERMEDIUS
22-Sep-16

18. 18
• Muscles of facial
expression, scalp,
auricles, platysma,
stylohyoid and the
posterior belly of digastric.
Motor
root
• Conveys from CHORDA TYMPANI:
gustatory fibers from presulcal area of
tongue.
• From the palatine and greater petrosal
nerves: taste sensations from soft palate.
• Preganglionic parasympathetic
secretomotor fibers of
SUBMANDIBULAR and SUBLINGUAL
SALIVARY GLANDS, LACRIMAL
GLANDS and GLANDS OF NASAL and
PALATINE MUCOSAE
Sensory
root
22-Sep-16

19. 19 22-Sep-16

20. MOTOR NUCLEUS
20
Deep in the reticular
formation
Represents the
BRANCHIAL EFFERENT
COLUMN
Nucleus receives fibers from
both CORTICONUCLEAR
TRACTS
Contralateral corticonuclear
fibers supply lower half of the
face
Corticonuclear projection to
22-Sep-16

21. 21 22-Sep-16

22. 22
In the RETICULAR
FORMATION
DORSOLATERAL to the
CAUDAL end of the motor
nucleus
Form the General Visceral
Efferent column
Sends fibers to sensory root,
via the chorda tympani
ultimately reach the
submandibular and
sublingual glands through
the submandibular ganglion
Preganglionic fibers reach
the pterygopalatine ganglion
22-Sep-16

23. 23
SENSORY NUCLEUS
Lies at rostral (front)
end of NUCLEUS
SOLITARIUS
In the MEDULLA
OBLONGATA
Receives
GUSTATORY
AFFERENTS
22-Sep-16

24. Course & Relations
WITHIN THE MEATUS
24
The two roots enter the internal acoustic meatus in a
groove on the 8th cranial nerve. Minute filaments
connect the facial nerve with the vestibulocochlear
nerve. 22-Sep-16

25. 25
•Laterally above the vestibule
•Runs backwards in relation to medial wall of middle ear above the
PROMONTARY
•Vertically downwards behind PROMONTARY
WITHIN THE CANAL
22-Sep-16

26. 26
Nerve undergoes a sharp bend of 130° lies over the antero-superior
part of PROMONTARY (GENU)
Hence the name GENICULATE GANGLION
•Second bend is gradual and lies between the promontary and the
aditus to the mastoid antrum
WITHIN THE PETROUS TEMPORAL BONE
22-Sep-16

27. 27
LEAVES THE SKULL THROUGH THE STYLOMASTOID FORAME22-Sep-16

28. 28 22-Sep-16

29. 29
Crosses the lateral side of
the STYLOID process
Enters posteromedial surface of the
PAROTID GLAND
Crosses the retromandibular vein and
external carotid artery
Divides into five terminal branches behind
the neck of the mandible
Emerge along the anterior border of
parotid gland
EXTRACRANIAL COURSE
22-Sep-16

30. 30
PES ANSERINUS (GOOSE FEET)
22-Sep-16

31. COMMUNICATING BRANCHES
31
INTRACRANIAL
Vestibulocochlea
r
FACIAL CANAL
Auricular
branch of
vagus
GENICULATE
GANGLION
Pterygopala
tine
ganglion via
the
GREATER
PETROSAL
NERVE
Otic ganglion
via the
LESSER
PETROSAL
NERVE
Middle
meningeal
sympathetic
plexus 22-Sep-16

32. 32
At the exit from
STYLOMASTOID
foramen
To glossopharyngeal,
vagus, great auricular
and auriculotemporal
nerves
Post-
Auricular
To the
LESSER
OCCIPITAL
NERVE
22-Sep-16

33. 33
FACIAL
With the
TRIGEMINAL
NERVE
CERVICAL
With the
TRANSVERSE
CERVICAL
NERVE
22-Sep-16

34. 34
GREATER
PETROSAL
NERVE
Begins from the
geniculate
ganglion
Carries taste
fibers from
palatal mucosa
Preganglionic
fibers to
pterygopalatine
ganglion
Relayed through the
zygomatic and lacrimal
nerves to lacrimal gland
Through the nasal and
palatine nerves to the
nasal and palatine
glands 22-Sep-16

35. 35
DEEP PETROSAL NERVE
The greater petrosal nerve
traverses the hiatus on the
anterior part of the petrous
temporal bone
Enters a groove
Passes under the
trigeminal ganglion to the
foramen lacerum
Joined by the DEEP
PETROSAL NERVE
This forms the NERVE TO
PTERYGOID CANAL
Traverses the canal and
ends in the pterygopalatine
ganglion
22-Sep-16

36. BRANCHES OF DISTRIBUTION
36
• Nerve to stapedius
• Chorda tympani
In the
facial canal
• Posterior auricular
• Digastric (posterior belly)
• Stylohyoid
At exit from
stylomastoi
d foramen
• Temporal
• Zygomatic
• Buccal
• Marginal mandibular
• Cervical
On the face
22-Sep-16

37. THE NERVE TO STAPEDIUS
37
 Behind the pyramidal eminence of the posterior
wall of the tympanic cavity, passes forwards
through a small canal to reach the muscle
22-Sep-16

38. THE CHORDA TYMPANI
38
 Leaves the facial
nerve about 6mm
above the
stylomastoid foramen,
ascending forwards in
a canal to perforate
the posterior wall of
the tympanic cavity
 Runs medial to the
handle of malleus to
re-enter the bone via
its anterior canaliculus
at the medial end of
the pterygotympanic
fissure
 Descends ventrally on
the medial surface of
the sphenoid spine 22-Sep-16

39. 39
Joins the
posterior
aspect of
lingual nerve
at an acute
angle.
Contains efferent preganglionic parasympathetic
(secretomotor) fibers which enter submandibular
ganglion.
From here post ganglionic fibers are relayed to the
submandibular and sublingual glands.
Most fibers are afferent from the mucosa of the
anterior, presulcal part of the tongue, constituting for
taste sensation for the lingual region.
22-Sep-16

40. 40
Before it
unites
with the
lingual
nerve it is
joined by
a small
branch of
the OTIC
GANGLIO
N
22-Sep-16

41. THE POSTERIOR AURICULAR NERVE
41
Arises near the stylomastoid foramen
Ascends in front of the mastoid process
22-Sep-16

42. 42
Joined by the auricular
branch of VAGUS NERVE
and communicates with
GREAT AURICULAR AND
OCCIPITAL BRANCHES.
As it ascends between the
EXTERNAL ACOUSTIC MEATUS and
the MASTOID PROCESS
AURICULAR OCCIPITAL
22-Sep-16

43. 43
AURICULAR
Auriculari
s
posterior
Intrinsic
muscles on
the auricle’s
cranial
aspect
OCCIPITAL
Occipital
belly of
OCCIPITOFR
ONTALIS
22-Sep-16

44. THE DIGASTRIC BRANCH
44
Starts at the
stylomastoid
foramen, dividing
into multiple
filaments which
supply the
posterior belly of
the digastric
22-Sep-16

45. THE STYLOHYOID BRANCH
45
Frequently arises with
the digastric branch
Enters the middle part
of the STYLOHYOID
MUSCLE.
22-Sep-16

46. THE TEMPORAL BRANCHES
46
Cross the Zygomatic arch to
reach the Temple and join the
ZYGOMATICOTEMPORAL
branch of maxillary nerve and
AURICULOTEMPORAL
branch of mandibular nerve.
These branches supply the FRONTAL BELLY OF
OCCIPITOFRONTALIS , ORBICULARIS OCULI,
CORRUGATOR SUPERCILI
Join the SUPRAORBITAL and the LACRIMAL
branches of the OPHTHALMIC NERVE
22-Sep-16

47. THE ZYGOMATIC BRANCHES
47
 Cross the zygomatic bone to the lateral canthus
of the eye, supplying the ORBICULARIS OCULI
and joining filaments of the LACRIMAL NERVE
and ZYGOMATICOFACIAL branch of the
maxillary nerve.
22-Sep-16

48. THE BUCCAL BRANCHES
48
 Pass horizontally
 Distribution is below the orbit and around the
mouthSUPERFICIAL
• Superficial
muscles
UPPER DEEP
• Pass under
and supply the
zygomaticus
major and the
levetor labii
superioris
Levetor anguli
oris,
zygomaticus
minor, levetor
labii superioris
alaque nasi
and small
nasal
branches
LOWER DEEP
• Buccinator
and
orbicularis
oris,
• Joins
filaments of
the buccal
branch of
mandibular
nerve
22-Sep-16

49. THE MARGINAL MANDIBULAR
BRANCHES
49
 Runs forwards below
the angle of the
mandible under the
platysma
 Turns upwards and
forwards across the
body of the mandible
to pass under the
depressor anguli oris
 Supplies the Risorius
and muscles of lower
lip and chin
 Joins the mental nerve
22-Sep-16

50. THE CERVICAL BRANCH
50
Arises from the
lower part of the
parotid gland.
Supplies the
PLATYSMA.
Communicates with
the TRANVERSE
CUTANEOUS
CERVICAL NERVE
22-Sep-16

51. ASSOCIATED GANGLIA
51
 THE GENICULATE GANGLION
 THE SUBMANDIBULAR GANGLION
 THE PTERYGOPALATINE GANGLION
22-Sep-16

52. THE GENICULATE GANGLION
52
Located at the
first bend
within the
canal in
relation to the
medial wall of
middle ear
Sensory
ganglion
Taste fibers
present in the
nerve are
peripheral
processes of
pseudo-
unipolar
neurons
present in the
ganglion22-Sep-16

53. THE SUBMANDIBULAR
GANGLION
53
•Small, fusiform body
•Is a PERIPHERAL
PARASYMPATHETIC
GANGLION
•Superior to deep part of
submandibular gland and
inferior to lingual nerve
suspended by filaments
•Is FUNCTIONALLY
related to the FACIAL
NERVE and CHORDA
TYMPANI
22-Sep-16

54. THE PTERYGOPALATINE
GANGLION
54
Parasympathet
ic ganglion.
Secretomotor
fibers to
lacrimal gland
relay at this
ganglion.
Fibers reach
the ganglion
from the nerve
to the
pterygoid
canal. 22-Sep-16

55. APPLIED ANATOMY
55 22-Sep-16

56. 56
Rainer Schmelzeisen et al. reported following
causes of facial nerve palsy in 1999
 Congenital
 Neurologic
 Neoplastic
 Infectious
 Iatrogenic
 Traumatic
 Other causes
22-Sep-16

57. FACIAL NERVE PALSY
57
 Bell’s palsy
 Supranuclear and infranuclear lesions and stroke(CVA) due to
lacunar infarcts
 Moebius syndrome(underdevelopment of the nerve at birth) ,
Miescher-Melkerson Rosenthal syndrome(recurring facial
palsy, swelling of upper lip, development of folds and furrowed
tongue)-bilateral palsy
 Guillain- Barre syndrome( autoimmune condition of peripheral
nervous system), multiple sclerosis, myasthenia gravis
 Tumors, Schwannoma, Glomus tumors, neuromas, congenital
cholesteatomas, hemangiomas, acoustic neuromas, parotid
tumors, metastasis of other tumors
 Otitis media- otorrhoea, hearling loss, otalgia,
cholesteatoma(destructive expanding keratinised growth of
squamous epithelium in middle ear and/or mastoid process),
Mastoiditis
 Lymes disease(Borrelia burgdorferi)(bacteria spread through
the nervous system causing facial nerve damage leading to
unilateral weakness or paralysis of facial muscles,
22-Sep-16

58. 58
 Heerfortd’s Syndrome/ Heerfortd’s-Mylius Syndrome,
Heerfortd’s-Waldenstrom Syndrome, Waldenstrom
uveoparotitis(uveitis, parotitis, chronic fever, facial palsy in
some cases)(hereditary/ mycobacteria, propionibacteria)
 Ramsay Hunt’s Syndrome
 Complications of parotidectomy
1. Intra-operative- Transection of facial nerve (incision is always
given horizontal)
2. Post-operative- Facial nerve paralysis, facial sinkinesis after
facial palsy, cosmetic deformity
 Trauma- transverse fractures of temporal bone in horizontal
plane, gunshots, lacerations
 Diabetes mellitus(vascular>metabolic-site of lesion is distal to
chorda tympani causing diabetic mono-neuropathy due to facial
nerve ischemia leading to disturbance of taste)
 Burning mouth syndrome-due chorda tympani hypofunction
leading to disturbance of taste, burning and tingling sensation)
 Bell’s palsy in pregnancy-(attributed to high extracellular fluid
content, viral inflammation, and immuno-suppression occurring
rd
22-Sep-16

59. 59
FACIAL PARALYSIS
INFRANUCLEA
R LESION
INVOLVING LOWER
MOTOR NEURON
SUPRANUCLE
AR LESION
INVOLVING UPPER
MOTOR NEURON
Contra-lateral Lower part
of the face is affected
Ipsilateral upper and lower
quadrant of the face is
affected 22-Sep-16

60. 60
LOWER MOTOR NEURON v/s UPPER MOTOR NEURON
The upper half of face has bilateral representation while lower has
ipsilateral representation
22-Sep-16

61. 61
BELL’S
PALSY
Lesion at
stapedius
Loss of taste
sensation in anterior
two thirds of tongue
except circumvallate
papillae
Hyperacusis
Lesion above
Chorda
tympani
Loss of taste
sensation in anterior
two thirds of tongue
except circumvallate
papillae
22-Sep-16

62. FACIAL NERVE PALSY IN
NEWBORN
62
 The mastoid process is absent in newborn
 Stylomastoid foramen is superficial
 Manipulation of baby’s head during delivery
may damage the facial nerve
 Leading to paralysis of facial muscles
especially buccinator used for suckling
22-Sep-16

63. RAMSAY HUNT SYNDROME
63
 Involvement of the GENICULATE GANGLION by
HERPES ZOSTER
22-Sep-16

64. 64 22-Sep-16

65. REFERENCES
65
 GRAY’S ANATOMY-37th edition
 B.D. CHAURASIA-5th edition
 HUTCHISON’S CLINICAL METHODS-23rd edition
 Neelima Malik-3rd edition
 Ragona R. M, Fillips C. D, Marioni G, Staffieri A.
Treatment of complications of parotid gland surgery 2005
Jun;25(3):174–78.
 Pecket P, Schattner A. Concurrent Bell’s palsy and
diabetes mellitus: a diabetic mononeuropathy?
1982;45:652-55.
 Eliav E, Kamran B, Schaham R, Czeminski R, Gracely
RH, Benoliel R. Evidence of chorda tympani dysfunction
in patients with burning mouth syndrome J AM DENT
ASSOC 2007 May;138(5):628-33.
22-Sep-16

66. 66 22-Sep-16