this presentation gives a brief view of the anatomy of the trigeminal nerve and facial nerve with applied aspects from a dentists point of view

1. GOOD
MORNING

2. ANATOMY OF TRIGEMINAL AND
FACIAL NERVE
Seminar - 2

3. • Terminologies
• Introduction to cranial nerves
• Trigeminal nerve
Development
Nucleus
Course and Branches
Ganglions associated
Applied aspect
• Facial nerve
development
origin
Course & Branches
Ganglions associated
Applied aspect
• Conclusion
• References
Contents

4. Terminologies
Nerve : A bundle of fibers that uses chemical and electrical
signals to transmit sensory and motor information
from one body part to another.
Sensory Nerve : A nerve that passes impulses from receptors
towards or to the CNS
Motor Nerve : Any nerve that transmits impulses from the
CNS – muscles/ organs.

5. Afferent Nerve- A nerve conveying impulses from the
periphery to the CNS.
Efferent Nerve : A nerve conveying impulses from the
CNS to the periphery.
GANGLION : Is a tissue mass that contains the dendrites and
cell bodies of nerve cells.

6. NUCLEI : Group of nerve cells within the CNS bearing a
direct relationship to the fibers of a particular nerve
PREGANGLIONIC FIBERS : In the ANS, fibers from CNS to the
ganglion.
POST GANGLIONIC FIBERS :In the ANS, fibers from ganglion to
the effector organ

7. • SYNAPSE : a specialized junction at which a nerve cell
communicates with a target cell.
• NEURALGIA: intense burning or stabbing pain caused by
irritation or damage to a nerve.

8. Introduction to
Cranial Nerves

9. Trigeminal nerve
• Largest of the cranial nerves
• Fallopian and Meckel described it in 1748.
• The name “Trigeminal “was given by Winslow on account
of its 3 divisions.
• tri- 3 gemini- twins
• Components GSE + BE
• DENTIST nerve

10. Development

11. Nucleus
• Chief Sensory Nucleus Of TGN
• Spinal Nucleus Of TGN
• Mesencephalic Nucleus
• Motor Nucleus

12. Functional Components
Componen
t
Nucleus Ganglion Function
General
sensory
(afferent)
Trigeminal
nucleus
Trigemina
l
ganglion
For general sensation from the face and anterior
scalp as far posteriorly as the apex of the head,
conjunctivae, bulb of the eye, mucous membranes
of paranasal sinuses, and nasal and oral cavities
including the tongue and teeth, part of the
external aspect of the tympanic membrane, and
from the meninges of the anterior and middle
cranial fossae
Branchial
motor
(efferent)
Masticator
nucleus
To innervate the muscles of mastication:masseter,
temporalis, medial and lateral pterygoid muscles
plus tensores tympani, tensores veli palatini,
mylohyoid, and anterior belly of the digastric
muscles

13.  Emerge from two roots on the ventro lateral surface of
the pons.
 Large sensory root and small motor root
 Sensory has a swelling called the Trigeminal Ganglion
located in a fossa on the petrous part of the Temporal
bone.
Course
Trigeminal ganglion /semi lunar
Cresent shaped
Lies in a depression over the anterior
aspect of the petrous temporal bone
near its apex.
Within a pouch recess of dura mater
– TG cave & closely related to
posterior end of cavernous sinus.
Anteriorly- convex border - V1, V2,
V3.
Posteriorly- TGN

14. Course and branches
pons at its junction with middle cerebellar peduncle
Forward and laterally over petrous bone
Trigeminal ganglion
Opthalmic (runs forward into lateral wall of cavernous sinus)
Lacrimal nerve
fronatal Naso ciliary
V3- mandibular nerveMaxillary nerve

15. Ophthalmic nerve
• Smallest
• Purely sensory
• Approx. 26,000 myelinated fibres.
• Arises from anteriomedial end of trigeminal ganglion as a flat
band 2.5 cm long
• Forms the affernet limb of corneal reflex

17. Ophthalmic nerve

18. Applied : Corneal reflex

19. Maxillary Nerve V2
• From the middle of the ganglion
• Sensory
• Intermediate size
• Carries the afferent limb of sneeze reflex

20. Course &Branches
Within the
cranium
• Middle meningeal
nerve
• -Receives ramus from
internal carotid
sympathetic plexus
• - Supply the middle
cranial fossa
In the
pterygopalatine
fossa
• Zygomatic nerve
• Pterygopalatine nerves
• The Nasopalatine
Nerve
• The Palatine branches
• The Pharyngeal
branch
In the
infraorbital
canal
• MSA nerve
• ASA nerve
On the face
• Inferior palpebral
• External nasal
• Superior labial
branches

21. Trigeminal ganglionV2
Foramen rotundum
Pterygo Palatine nerve
Meningeal branch from MCF
ASA
PSA
V2
MSA
Superior labial
Nerve
Zygomatico temporal
infra orbital nerve &
foramen
Zygomatico facial
Zygomatic nerve

23. TWO GANGLIONIC BRANCHES
- Connect the nerve with
pterygopalatine ganglion
- Contain secretomotor fibres
from lacrimal gland
- Secretory fibres from orbital
periosteum and mucous
membrane of nose, palate and
pharynx
IN THE PTERYGOPALATINE FOSSA
Palatine branches
oAnterior palatine - palatal soft
tissue and bone as anterior as
premolar parts of soft palate
oMiddle palatine - mucous
membrane of soft palate
oPosterior palatine - tonsillar
region
Pharyngeal branch
- Mucous membrane of pharynx
Orbital branch
- Periosteum of orbit and orbitalis
muscle
Nasal branch
- Superior and middle conchae
- Roof of nose and nasal septum
- Naso palatine nerve : incisal
teeth and supporting structure
Lacrimal branch
- Communicating branch to
lacrimal nerve.

24. On the face
INFERIOR PALPEBRAL BRANCHES
• Supply the skin of lower eyelids
• Joins the facial and zygomaticofacial nerve near lateral
canthus
EXTERNAL NASAL BRANCHES
• Supplies the skin of side of nose ,nasal septum
SUPERIOR LABIAL BRANCHES
• Supply the skin of the superior part of the cheek, upper lip,
oral mucosa, labial glands
• Joined by the facial nerve to form the infra orbital plexus

25. Applied aspect
Trigeminal neuralgia –
Anesthetize the nerve at foramen rotundum
Referred pain from sinusitis- upper teeth and skin over
infra orabital region.

26. Mandibular Nerve V3
• The largest division
• Arises from the most anterolateral part of the trigeminal
ganglion
• It is the nerve of first branchial arch
• Supplies all the structures derived from it

27. Course & Branches

28. Branches
Main trunk
• Nervus spinosus
• Medial pterygoid nerve
Anterior division
• Nerve to masseter
• Nerve to lateral
pterygoid
• Deep temporal nerve
• Long buccal nerve
Posterior division
• auriculotemporal
• Lingual nerve
• Inferior alveolar nerve

30. Lingual nerve

31. Applied aspect
Jaw-jerk reflex
-supplies both afferent and efferent loops
- Tapping of the chin causes contraction of pterygoid muscle.
refered pain in ear and temporal fossa- carcinoma tongue
-close to auriculotemporal nerve
Lesions at foramen ovale-
Parasthesia- mandible,tongue temporal region
Paralysis – muscles of mastication , loss of jaw jerk reflex.
3rd molar extraction/ angle of mandible fracture
- Loss of sensation from 2/3rd of tongue.

32. Inferior alveolar nerve
Injury - Altered sensation over the chin

33. Ganglions associated
with TGN
• Non synaptic but receive communication
- tensor tympani (from trigeminal motor nucleus)
- tensor veli palatini (from trigeminal motor nucleus)
- levator veli palatini (from Facial nerve)
• Innervates - Parotid gland
• Pre-ganglionic parasympathetic from Glossopharyngeal
nerve through Lesser Petrosal nerve
• Post-ganglionic sympathetic to plexus around middle
meningeal artery
The Otic Ganglion:

34. The Pterygopalatine
Ganglion
• Nasal ganglion, Meckel’s ganglion, Sphenopalatine ganglion,
Ganglion of hay fever.
• Flattened reddish grey in color
• Associated with the Maxillary nerve(palatine nerves).
• Parasympathetic root:
- Facial nerve (preganglionic)
- Lacrimal nerve of Ophthalmic division (post-ganglionic)
- Lacrimal gland, Nasal, Palatine and Pharyngeal glands
• Sympathetic root from superior cervical ganglion

35. • The Submandibular
Ganglion
• Innervates submandibular and
sublingual salivary glands.
• Preganglionic parasympathetic:
from superior salivatory
nucleus(medulla) via Lingual
nerve
• Postganglionic parasympathetic: to
oral mucosa, submandibular and
sublingual salivary glands.

36. The Ciliary Ganglion:
• Motor Root:
Preganglionic to
Pupillary sphincter,
Ciliary muscles of Iris
• Sensory Root:
Postganglionic to
Radial fibres of dilator
pupillae
• Sympathetic Root: fibers
from Cavernous sinus

37. Applied aspect

39. Loss of pain and
temperature sensation in
ipsilateral side of face
Loss of ipsilateral
discriminative touch and
muscles of mastication is
affected
All sensory modalities on
the opposite side are
afffected

40. Features
• Loss of general sensation from face and mucous membrane of
nasal and oral cavities.
• Loss of corneal reflex.
• Flaccid paralysis of masticatory muscles.
• Jaw deviates to the side of lesion – unopposed lateral
pterygoid
• Hypoaccusis

41. Clinical Examination
• SENSORY EXAMINATION
 descriminative touch pathway
 Pain and temperature pathway
 Simple touch pathway
 Corneal reflex

42. MOTOR EXAMINATION
Clench the jaw
Opening of the mouth
Side to side movement of the jaw
Jaw-jerk reflex

43. Trigeminal neuralgia
• Trigeminal neuralgia, also known as “tic douloureux”
(painful spasm), is a condition in which excruciating
paroxysms of pain occur in one or more divisions of the
trigeminal nerve.
• The pain is typically lancinating in character and lasts a few
seconds.
• “Trigger zones“

44. • Diagnosis: classic symptoms and signs, anestheic blocks at
trigger points to differentiate trigeminal neuralgic pain from
neuritic pain.
• Treatment:
• Medical:
- This is the first line of treatment
- analgesics, sedatives, vit-B12 injections(earlier),
antiepileptics(phenytoin, carbamazepine).
• Surgical:
- alcohol injections, peripheral neurectomy,
decompression, excision of afferent tracts.

45. Trigeminal neuritis/neuromyopathy
• Burning, boring, pulling, drawing or pressure type of ache
• Due to dental surgical procedures, tumors, intracranial
aneurysms.
Paratrigeminal/Raeder’s Syndrome
• Severe headache with ocular paralysis
• Homolateral pain with sweating
• Unknown cause and seen more in males

46. Sphenopalatine Neuralgia
• Horton’s syndrome / Vidian nerve neuralgia / Sluder’s
headache / “Alarm clock” headache
• Caused by vasodilatation of internal maxillary artery
• Unilateral paroxysms of intense pain in the region of eye,
ear, maxilla,mastoid, base of nose with a rapid onset of
pain persisting for 15 minutes to several hours.
Atypical Facial Neuralgia
• Vague, deep, poorly localized pain in regions of V, IX
cranial nerves and II, III cervical nerves distribution
• Unanatomic distribution of pain, persists for long duration
• Diagnosis of exclusion

47. Facial nerve

48. Facial nerve
 It is the nerve of the second branchial arch.
 The facial nerve attaches to the lateral surface of the
brainstem, between the pons and medulla oblongata.
 large motor root and a smaller sensory root(the
intermediate nerve/ nerve of Wrisberg).
 The intermediate nerve - SA fibres (taste),the
parasympathetic GVE fibres and the GSA fibres.
 The larger motor root contains the BE fibres.

49. Embryology

50. Nucleus
• Motor Nucleus /branchiomotor
• Superior salivary nucleus /parasympathetic
• Special lacrimatory nucleus
• Nucleus of tractus solitarius

51. Functional components
Component Nucleus Ganglion & Cell of
Origin
Function
General
sensory
(afferent
Pontine
trigeminal
nucleus (for
touch) Spinal
trigeminal
nucleus (for
pain)
Geniculate
ganglion
For general sensation from a small
variable area of the concha of the
external ear (pinna/ auricle), external
acoustic meatus, and external (lateral)
surface of the tympanic membrane, and a
small area of skin behind the ear
Special
sensory
(afferent)
Nucleus solitarius
(rostral gustatory
portion)
Geniculate
ganglion
Taste buds
For taste sensation from the anterior
two-thirds of the tongue and
soft palate
Branchial
motor
(efferent)
Motor nucleus of
cranial nerve VII
To innervate the muscles of facial
expression
Parasympatheti
c
motor (visceral
efferent)
Superior
salivatory
nucleus
Pterygopalatine
and submandibular
ganglia
To stimulate the lacrimal,
submandibular, and sublingual
glands as well as the oral, nasal,
and pharyngeal mucosal glands
Component Nucleus Ganglion & Cell of Origin Function
General
sensory
(afferent)
Pontine trigeminal
nucleus (for touch)
Spinal trigeminal
nucleus (for
pain)
Geniculate
ganglion
For general sensation from a small variable area of
the concha of the external ear (pinna/ auricle),
external acoustic meatus, and external (lateral)
surface of the tympanic membrane, and a small area
of skin behind the ear
Special
sensory
(afferent)
Nucleus solitarius
(rostral gustatory
portion)
Geniculate
ganglion
Taste buds
For taste sensation from the anterior two-thirds of
the tongue and soft palate
Branchial
motor
(efferent)
Motor nucleus of
cranial nerve VII
To innervate the muscles of facial
expression
Parasympathetic
motor (visceral
efferent)
Superior salivatory
nucleus
Pterygopalatine
and submandibular
ganglia
To stimulate the lacrimal,
submandibular, and sublingual
glands as well as the oral, nasal,
and pharyngeal mucosal glands

52. Course & Branches

53. • Intra cranial part
INJURY - LOSS OF LACRIMATION,LOSS OF STAPEDIAL REFLEX,LOSS OF TASTE
FROM ANTERIOR 2/3RD OF TONGUE,LOSS OF SALIVATION AND FACIAL MUSCLE
PARALYSIS
• Infra temporal part
INJURY - CAUSE LOSS OF STAPEDIAL REFLEX,LOSS OF TASTE,LOSS OF SALIVATION AND
LOSS OF FACIAL EXPRESSION.
• Extra-cranial Part
INJURY – LOSS OF FACIAL EXPRESSION
FORCEPS DELIVERY-
LESS DEVELOPED MASTOID PROCESS.- FACIAL NERVE INJURY

54. Branches of distribution

55. Applied aspect
The intimate relationships between the facial nerve and the parotid gland mean that surgical
removal of the parotid gland is a difficult dissection if all branches of the facial nerve are to
be spared.

56. Branches of
communication
1) In Internal acoustic meatus
• With VIII nerve
2) At Geniculate ganglion
• With pterygopalatine ganglion through greater petrosal
nerve
• With Otic ganglion by a branch joining lesser petrosal nerve
3) In Facial canal
• With auricular branch of vagus

57. 4)Below Stylomastoid canal
• With IX,X,auriculotemporal and greater auricular nerves
5) In the face
• With branches of V nerve
6) In the neck
• With transverse nerve of the neck

58. The facial nerve is responsible for:
I. Contraction of the muscles of the face
II. Production of tears from a gland (Lacrimal gland)
III. Conveying the sense of taste from the front part of the
tongue (via the Chorda tympani nerve)
IV. The sense of touch at auricular conchae

59. Ganglions associated
• GENICULATE GANGLION:
- Sensory ganglion.
- The taste fibers present in the nerve are peripheral processes
of pseudounipolar neurons present in geniculate ganglion.
• SUBMANDIBULAR GANGLION
• PTERYGOMANDIBULAR GANGLION

60. Applied aspect
• Upper motor neuron lesions
• Lower motor neuron lesions
• Bells palsy

61. Clinical examinations
1. Function of muscles of
facial expression
2. Taste from the taste buds
3. Somatic sensation from
exernal ears.
4. Function of stapedius
5. Secretomotor innervation
of lacrimal and salivary
gland

63. Bells palsy

64. Syndromes associated
with facial palsy
• Ramsay hunt syndrome
• Melkersson Rosenthal syndrome
• Guillain Barre syndrome
• Moebius syndrome

65. Conclusion
• As dental professionals an understanding of the basic
components of the nervous system as well as the major nerves of
the head and neck is required. Differential diagnosis of the
source, cause of the pathology in the facial area, requires an in
depth knowledge of the structures, their relations , functions
and deviations that occur in the disease. A through knowledge
of the 5th and 7th cranial nerve is necessary since it provides
innervation of majority structures of orofacial region.

66. References
• Chaurasia BD, human anatomy.5th ed.P.157-62,354-7.
• Malamed SF. Handbook of local anesthesia.5th ed.P.170-84
• Singh V. Text book of clinical neuroanatomy.2nd ed.P.90-110
• Pauwels lw, stewart pa, akesson ej, spacey sd. CRANIAL
NERVES function and dysfunction 3rd ed.p.83-110. 119-142.
• Drake RL, vogl AW, mitchell AWM. Gray’s anatomy for
students 2nd ed.P.

67. Thank
you