The facial nerve is the 7th cranial nerve with motor, parasympathetic, and sensory components. It has nuclei in the pons and medulla. The nerve exits the pons and travels through the internal acoustic meatus into the Fallopian canal. It gives off branches like the chorda tympani and exits at the stylomastoid foramen. Damage can cause Bell's palsy or Ramsay Hunt syndrome. Studies have mapped the nerve's relationship to anatomical landmarks to safely guide surgery on structures like the mandible and zygomatic arch.

1. FACIAL NERVE (CN VII)
Guided By:
Dr. Abhinav Srivastava
Reader
Presented By:
Dr. Yogendra Rawat
JR I, Oral & maxillofacial
surgery
SPPGDMS

2. CONTENTS:
• Introduction
• Nuclei Component
• Course of Facial nerve
• Branches of facial nerve
• Clinical Significance
• Examination of facial nerve
• References

3. Introduction
• Facial nerve is the seventh cranial
nerve.
• The facial nerve is a
predominantly.
a motor nerve with
parasympathetic and a sensory
components.
• It is the nerve of second brachial
arch.

4. Nuclei Component:
There are mainly two roots.
-Large motor root (Facial nerve proper)
General somatic efferent: motor supply
facial muscles
-Small sensory root (nervus
intermedius)
General visceral efferent:
parasympathetic secretomotor supply to
submandibular and sublingual salivary
glands and the lacrimal gland)

5. Special visceral afferent: taste
sensation from anterior two-thirds
of the tongue)
General somatic afferent:
cutaneous sensations from the
pinna and the external auditory
meatus.

6. Motor nucleus
Its deeper, lying ventrolateral in pontine
reticular formation, posterior to the dorsal
trapezoid nucleus & ventromedial to the
trigeminal spinal tract and nucleus.
The upper motor neuron (UMN) of the
facial nerve is located in the primary motor
cortex of the frontal lobe. UMN axons
descend ipsilaterally as the corticobulbar
tract via the genu of the internal capsule and
reach the facial nucleus in the pontine
tegmentum.

7. Sensory nucleus
• This is the rostral end of the
nucleus solitarius in the medulla
oblongata
• The nervus intermedius
carries
parasympathetic (general
visceral efferent) fibers. These
fibers arise from the superior
salivatory nucleus.

8. Special visceral afferent fibres
arising from the Nucleus of
tractus solitarius.
General somatic afferent fibres
arising from the spinal nucleus
of trigeminal nerve.

9. COURSE OF FACIAL NERVE
INTRAPONTINE COURSE:
• Fibers from the motor nucleus
course through the pons taking a
sharp bend around the abducent
nucleus.
• Thus producing internal genu of
the facial nerve.

10. • Finally they pass between their
own nucleus medially and the
spinal trigeminal nucleus
• They leave the pons through
pontomedullary junction.

11. Intracranial course:
The two roots of the facial nerve
pass laterally and forward in the
cerebellopontine angle along with
vestibulocochlear nerve and
labyrinthine artery.
• These structures together enter
the internal acoustic meatus.
• In the distal end of the internal
acoustic meatus, the facial
nerve [VII] enters the fallopian
canal(facial canal) & continues
laterally.

12. COURSE INSIDE THE FALLOPIAN CANAL
LABRINTHINE SEGMENT:
• Meatal foramen to the region of the
facial canal occupied by the
enlargement the first genu or turn of
the facial canal.
• The enlargement is the sensory
geniculate ganglion. At the geniculate
ganglion the facial nerve turns and
gives off the greater petrosal nerve.
(it supplies preganglionic
parasympathetic general visceral efferent
to the pterygopalatine ganglion)
LABRINTHINE
Tympanic
MASTOID

13. TYMPANIC SEGMENT:
• The tympanic segment starts
from the geniculate ganglion and
until the second bend of the
facial canal.
• In this segment the nerve passes
above stapes horizontally and
gives a branch nerve to
stapedius.
(It supplies general somatic
efferent to the stapedius muscle)
NERVE TO
STAPEDIUS

14. Mastoid segement:
• The mastoid segment starts from
the second bend of the facial
canal, going downwards, towards
the stylomastoid foramen.
• In this segment it gives off
chorda tympani which runs
posteriorly across the tympanic
membrane.
(It supplies SVA and GVE to the anterior
2/3rd of the tongue and to the
submandibular ganglion respectively).
CHORDA
TYMPANI

15. EXTRACRANIAL:
• After emerging from the
stylomastoid foramen, the facial
nerve gives two branches
(It gives (GSA) fibers to the pinna of the
ear and external auditory meatus and
(SVE) fibers to the posterior belly of
digastric, stylohyoid, the superior and
posterior auricular, and occipitalis
muscles)

16. Parotid divisions
• Through the parotid gland, it
branches into pes anserinus (i.e,
five terminating branches)
(It gives (GSE) fibres to the
muscles of the face)

17. Branches of the Facial Nerve:
Branches of the facial nerve inside
the Fallopian canal:
• The greater superficial petrosal nerve–
joins deep petrosal nerve (forms
sympathetic plexus around ica) – together
forms nerve to pterygoid canal (vidian
nerve) – joins pterygopalatine ganglion

18. • Small branch to the stapedius
muscle– supplies stapedius
muscle – it dampens excessive
vibrations caused by high pitched
sounds.
• The chorda tympani– it conveys
taste fibres from ant 2/3rd part of
tongue and pre ganglionic fibres
to submandibular ganglion.

19. Branches of the Facial Nerve
Immediately After it leaves the
stylomastoid foramen:
1.The posterior auricular nerve: Supplies
the occipital belly of occipitofrontalis,
superior and posterior auriculares
muscles.
2. The nerve to the posterior belly of the
digastric muscle
3. Nerve to stylohyoid muscle.
Posterior
auricular
nerve
DIGASTRIC
NERVE

20. Branches of the Facial Nerve
The five terminal branches of
the facial nerve:
1. Temporofacial division
Temporal nerve
Zygomatic nerve
2. Cervicofacial division.
Buccal nerve:
Marginal mandibular
nerve
Cervical nerve
TEMPORAL
Nerve
Temporofacial division
Cervicofacial division
Zygomatic
Nerve
Buccal
nerve
Marginal
mandibular
nerve
Cervical nerve

22. Clinical Significance

23. Damage to the facial nerve can have various etiologies
like:
• Trauma
• Stroke
• Iatrogenic
• Idiopathic Bell’s palsy
• Neoplasm
• granulomatous meningitis.
• Viral infections

24. 1. SUPRA NUCLEAR LESIONS – involves
upper motor neurons of corticobulbar tract.
results in loss or impairment of movements
of lower facial muscle of contralateral side.
2. NUCLEAR LESIONS – involves motor
nucleus of facial nerve along with abducent
nucleus. results in loss of movements of all
facial muscles of ipsilateral side,
associated with internal strabismus due to
involvement of lateral rectus muscle.
3. INFRANUCLEAR LESIONS – lesion
involving peripheral part of facial nerve –
known as bell’s palsy – involves facial
muscles of the affected side.

25. Idiopathic Facial Paralysis (Bell's Palsy)Criteria
• Unilateral
• Peripheral
• Acute onset
• No apparent cause
• Does not involve any
other cranial nerves
• Bell's phenomenon

26. Traumatic Facial Paralysis
• Traumatic rupture
• Stretch injury
• Nerve compression (by hematoma or
bone fragments)
• Trauma-induced swelling
• Thermal injury (from a drill during
surgical procedures)

27. RAMSAY HUNT SYNDROME
Due to involvement of geniculate
ganglion in herpes zoster infection
• Symptoms include–
1.Herpetic vesicles on auricle
2.Hyperacusis
3.Loss of lacrimation
4.Loss of sensation in anterior 2/3rd of
tongue
5.Bell’s palsy

28. CROCODILE TEAR SYNDROME
• Also known as Bogorad syndrome
• Patients recovering from nerve injury
lesion proximal to geniculate
ganglion
• cross innervations develop leading to
gustatory reflex.

29. APPLIED ANATOMY

30. DINGMAN RO AND GRABB STUDY (1962)
•OBJECTIVE
1. Define relations of marginal
mandibular branch of facial
nerve to the mandible to aid
in planning approaches to the
body and ramus of mandible.

31. Result
1. The marginal mandibular nerve
course runs anterior and
posterior to facial artery.
2. Posterior to facial artery,
mandibular ramus branch pass
above inferior border of
mandible in 81% cases and in
19% cases it passes below ;
within 1cm of inferior border of
mandible.
3. In 100% cases, nerve passes
superficial to anterior facial
vein.

32. APPLICATION OF DINGMAN AND GRABB STUDY
• Based on their study, authors
recommended skin incission to
approach body of mandible
extraorally placed
“ONE FINGER BREADTH
OR 2CM BELOW LOWER
BORDER OF MANDIBLE,
ALONG THE SKIN LINES,
TO AVOID DAMAGE OF
MARGINAL MANDIBULAR
BRANCH OF FACIAL
NERVE.”
Incision placed
2cm below the
lower border of
mandible

33. AL KAYAT A BRAMLEY P STUDY (1979)
• OBJECTIVE
1. To analyse the position of the facial nerve in relation to
easily identifiable landmarks. improve the visibility
and safety of the surgical approach to the zygomatic
arch and temporomandibular joint (tmj).

34. Observations
Observations were made on
56 facial halves
Point A Point B Range (in cm)
C Z 0.8-3.5
B F 1.5-2.8
PG F 2.5-3.5

35. OBSERVATION ON TEMPORAL FASCIA
1. Superiorly the temporal fascia is
a single, thick layer attached to
the entire extent of the superior
temporal line.
2. At about 2 cm above the
zygomatic arch the temporal
fascia divides into two layers,
one of which is attached to the
lateral aspect of the periosteum
of the zygomatic arch while the
other is attached to the medial
aspect.

36. 3) At the level of the zygomatic
arch, the periosteum firmly
blends with both the outer layer
of the temporal fascia and the
superficial temporal fascia. this
fusion of these three layers
forms a tough connective tissue
through which run the temporal
and zygomatic branches of the
facial nerve. in all cases it was
difficult to dissect out the nerves
without damaging them

37. NEW SURGICAL
APPROACH
• A “question mark” shaped
incision was made in the
temporal region with an
inferior preauricular/end aural
extension
• The temporal component is
made posterior to the temporal
vessels and is carried through
the skin and superficial
temporal fascia to the level
of the deep temporal fascia.

38. • Blunt dissection in this plane is carried
downwards to a point about 2 cm
above the zygomatic arch where the
temporal fascia splits and contains
fatty tissue, which is easily visible
through the thin lateral layer.
• Starting at the root of the zygomatic
arch, an incision running at 45°
upwards and forwards is made through
the superficial layer of the temporal
fascia

39. • Once inside this pocket, the
periosteum of the zygomatic
arch can be safely incised and
turned forwards as one flap
with the outer layer of
temporal fascia and the
superficial fascia. proceeding
downwards from the lower
border of the arch and
articular fossa, the tissues
lateral to the joint capsule are
dissected and retracted and
the tmj and the condyle can
be exposed.

40. Examination of facial nerve
• Visual examination:
• Asymmetrical expression
Patient to look upwards
Test strength
Determine any difference in tone
• Upper part of the face is relatively spared
in facial paresis of an upper motor neuron
• lower motor neuron lesion results in
paresis/paralysis of all the ipsilateral facial
muscles.

41. Examination of facial nerve
• Schirmer test(Tear test)
• Acoustic reflex

42. References
• GRAY’S ANATOMY
• BD CHAURASIA
• Neuroanatomy, Cranial Nerve 7 (Facial) article by Dominika
Dulak; Imama A. Naqvi. july 25, 2022.
• AL-KAYAT A, BRAMLEY P. A modified pre-auricular approach to
the temporomandibular joint and malar arch. br j oral surg 1979; 17:
91–103
• DINGMAN RO, GRABB WC. surgical anatomy of the mandibular
ramus of the facial nerve based on the dissection of 100 facial halves.
Plast reconstr surg. 1962; 29: 266–72

43. THANK YOU