1. TRIGEMINAL
NERVE
1

2. It is V and Largest cranial nerve
Mixed -- Small motor root
Large sensory root
Nerve of the first pharyngeal arch
2

3.  Exteroceptive from
Skin of the face & forehead;
Mucous membrane of the
nasal cavity;
Oral cavity;
Nasal sinus;
Floor of mouth, teeth;
Anterior 2/3 of tongue;
Cranial dura
Proprioception
from
 Teeth;
 Periodontium;
 Hard palate;
 TMJ
3

4. Attached to lateral part of pons
Sensory root (portio major)
Motor root (portio minor)
4

5. 5

6.  Fibers arise from Semilunar
Ganglion
 Semilunar ganglion
– Develops from neural crest
– Crescent shaped
– Unipolar neurons
– Location- Meckel’s cavity;
superior to petrous part of
temporal bone
6

7. 7

8. 8

9.  Afferent station
 Afferent fibers accompany fibers of motor root
 Proprioception from TMJ, periodontal membrane, teeth, hard
palate
 Afferent impulses from stretch receptors in the muscles of
mastication
9

10. 10

11. 11

12.  Located at midpontine level
 Medial to main sensory nucleus
 Fibres distribute to muscles of mastication,
mylohyoid, anterior belly of digastric, tensor
tympani, tensor veli palatini.
12

13.  Location – midpons
 Forms dorsal trigeminothalamic tract
 Ascending fibers terminate in this nucleus
 Convey light touch, tactile discrimination,
sense of position and passive movements
13

14.  True sensory ganglion
 Contains
cells
that
are
structurally
and
functionally ganglion cells
 Convey impulses from the muscles innervated by
the trigeminal nerve and the extraocular muscles,
as well as from the periodontal ligament of the
teeth
14

15.  Largest nucleus
 Extends caudally from main nucleus to level C3 of
spinal cord
 Forms ventral trigeminothalamic tract
 Conveys pain and temperature
15

16. extends to the
pontomedullary
junction inferiorly
pontomedullary
junction to obex
Tactile sense
Obex(medulla) to C3
level of spinal cord
Pain and temperature
16

17. 17

18. 18

19.  Smallest division
 From anterior medial part of semilunar ganglion
lateral wall of cavernous sinus
 Sensory fibres from Scalp, skin of forehead,
upper eyelid lining frontal sinus, conjunctiva
of eyeball, lacrimal gland, skin of the lateral
angle of eyeball & lining of ethmoid cell
19

20. Ophthalmic division
20

21. Short
ciliary
nerves
Long
ciliary n.
Infratrochlear
21

22. LACRIMAL NERVE (n. lacrimalis)
 Smallest branch.
 Enters the orbit through the narrowest part of the superior orbital
fissure
 Runs along the upper part of the lateral rectus
 Communicates with zygomatic branch of maxillary nerve.
 Enters the lacrimal gland – gives of several filaments
 Finally pierces the orbital septum & ends in supplying the skin of
upper eyelid.
22

23. FRONTAL NERVE (n. frontalis)
 Largest branch.
 Enters the orbit through the superior orbital fissure.
 Runs forward between levator palpebrae superioris and
periosteum
 Divides into two branches in the midway between the apex and
base of the orbit
 Supratrochlear
 Supraorbital
23

24. •
Supraorbital
Smaller than supratrochlear. Gives filament to join the
infratrochlear.
Supplies – Skin over the lower forehead.
Conjunctiva
Skin of the upper eyelid.
Supratrochlear
Passes through the supraorbital foramen.
Branches into medial & lateral.
Supplies – Conjunctiva.
Skin of the upper eyelid.
Twigs to pericranium.
24

25. Nasociliary Nerve (n. nasociliaris)
 Intermediate in size and more deeply placed.
 Enters the orbit between the two heads of rectus lateralis.
 Further passes through anterior ethmoidal foramen.
 Supplies internal nasal branches to mucous menbrane.
 Emerges as external nasal branch supplying the skin of the ala
and apex of the nose.
25

26.  Sensory
 From lower eyelid, side of the nose,
upper lip;
 All maxillary teeth & gingivae, mucous
membrane of most of nasal cavity, hard
and soft palate;
 Tonsillar region and region of pharynx
26

27. 27

28. 28

29. Sphenopalatine
ganglion
29

30. 30

31. Zygomaticotemporal:
 Exits the zygomatic bone on its medial surface
 Pierces the temporal fascia to supply skin
over temple
 Receives a branch from lacrimal nerve
 Communicates with facial nerve and
auriculotemporal branch
Zygomaticofacial
:
 Leaves zygomatic bone on its lateral surface
 Supplies skin over malar prominence
 Communicate with facial nerve & with inferior
palpebral branch of maxillary
31

32. Posterior superior alveolar nerves
• Arise in the pterygopalatine fossa
• Leaves maxillary nerve in pterygopalatine
fossa
• Enters the posterior alveolar canals
Branches to
 Sinus lining
 Three twigs to Molars
 Gingiva
 Adjoining part cheek
32

33. Middle superior alveolar nerves
• Arise from the nerve in the posterior part of the infraorbital canal
• Runs in infraorbital groove on the lateral wall max sinus
• Supply premolars, gingiva & adjoining part cheek
• Forms a superior dental plexus with anterior and posterior superior alveolar
branches
33

34. NTERIOR SUPERIOR ALVEOLAR NERVES
• Given off just before exiting from the infraorbital foramen.
• Supplies the incisor and canine teeth.
• Descends in canalis sinosus in anterior wall of maxillary sinus.
• Gives off a nasal branch to supply the mucous membrane of the anterior part
of inferior meatus and nasal floor.
• Communicates with the nasal branches of the sphenopalatine ganglion.
34

35. INNERVATION OF HARD PALATE
Sensory innervations
Greater palatine
Nasopalatine
These are branches of maxillary N passing through Pterygopalatine
ganglion
Lesser Palatine N ( middle & posterior ) – Uvula, tonsil, soft palate
Pterygopalatine ganglion
Greater palatine nerve
Lesser palatine nerve
35

36. 36

37. 37

38. 38

39. 39

40. 40

41. GANGLIONS
41

42. Ciliary ganglion
• Suspended from nasociliary nerve
• Anatomically belongs to trigeminal
nerve
• Functionally belongs to oculomotor
nerve
• Carries parasympathetic motor fibres
from Edinger – Westphal nucleus
42

43. OTIC GANGLION
• Suspended from mandibular nerve
• Anatomically belongs to trigeminal nerve but functionally
belongs to glossopharyngeal nerve
• Carries the secretomotor ( nucleus is superior salivary )fibres
& distributed via lesser superficial petrosal nerve to Parotid
glands.
43

44.  Suspended from lingual nerve
 Anatomically belongs to
trigeminal nerve but
functionally belongs to facial
nerve
 Carries the secretomotor
( nucleus is superior salivary )
fibres & distributed via chorda
tymoani nerve to
submandibular & sublingual
salivary glands.
44

45. PTERYGOPALATINE GANGLION
• Suspended from maxillary nerve
• Anatomically belongs to trigeminal nerve but functionally
belongs to facial nerve
• Carries secretomotor fibres & distributed via the great
superficial petrosal nerve ( Nucleus is inferior salivary ) to the
Lacrimal glands & the glands of the palate
45

46. 46

47. 47

48. 48

49. 49

50. 50

51.  Surgical removal of third molars(Von Arx and
Simpson, 1989; Rood, 1992)
 Osteotomies (Walter and Gregg, 1979; Yoshida et
al, 1989)
 Trauma (De Man and Bax, 1988)
 Tooth extractions (Strassburg, 1967; Hansen, 1980)
 Pulpectomy (Holland, 1994)
Experimental Trigeminal Nerve Injury G.R. Holland CROBM 1996 7: 237
51

52.  Implant placement
 Hydroxypatite ridge augmentation
 Endodontic surgeries
 Tumour resection
 Salivary gland and duct surgery
 Vestibuloplasty
 Biopsy procedures
52

53. • Inferior alveolar nerve injury – 0.41-7.5%
• Lingual nerve injury – 0.06-11.5%
53

54. 54

55. Risk factors for nerve injury
55

56.  Local anesthetic toxicity
 Formation of epineural hematoma
 Needle-barb mechanism of injury
 Chemical injury
56

57.  Sagittal split osteotomy
 Mandibular
osteotomies.
advancement
procedure
 Intraoral vertical ramus osteotomy (IVRO)
 Genioplasty procedures
57

58. 58

59.  Fracture of mandibular body and ramus
 LeFort I & II fractures
 Fracture of condylar segment medially
 Mandibular angle, body and symphysis fracture
 Inadvertent placement of screws
59

60. 60

61. 61

62.  Overinstrumentation
 Chemical injury
 Direct trauma from apicoecotomy
62

63.  TMJ exposures by preauricular approach
 Damage is minimized by incision and dissecting in
close apposition to cartilagenous portion of external
auditory meatus
 Fracture of neck of condyle
63

64.  Trigeminal neuralgia is defined as sudden, usually
unilateral, severe, brief, stabbing, lancinating type of
pain in the distribution of one or more branches of 5th
cranial nerve
 Specific etiology unknown
64

65.  Sudden, unilateral, intermittent paroxysmal, sharp,
shooting, lancinating, like pain.
 Pain is elicited by slight touching superficial ‘Trigger
points’
 Common triggers include touch, talking, eating,
drinking, chewing, tooth brushing, etc.
65

66. MEDICAL TREATMENT
DRUGS CURENTLY USED:1.Carbamazepine is used as a standard drug ,
adult dose 200mg TDS & can be increased upto 1600
mg/day in divided doses
initially started as small dose & gradually increased to
prevent side effects
adverse effects include dizziness, ataxia, vertigo, skin rashes
.
,etc
bone marrow suppression is rare but requires routine
.
monitoring
66

67. 2.Phenytoin sodium
usually used in combination of carbamazepine
dose 100-400mg/day
side effects: gum hyperplasia
3. Gabapentin
dose is 1200-3600mg/day
used with caution in patients with renal & hapatic disease
4. Gaba agonist
these drugs reduce the central projection of painful
impulses
eg. Baclofen , adult dose being 10-30 mg TDS
67

68. Surgical treatment
• Peripheral nerve block procedure: It involves blocking
of peripheral nerve by long acting LA.
• Alcohol block : 0.5 -2 ml of 95% alcohol can be used
for blocking of peripheral nerve.
• Blocking of gasserian ganglion: more effective but it
has hazards in sense that alcohol escape into the
surrounding subarchanoid space & may cause palsy of
adjacent cranial nerve.
68

69. • Post ganglionic sectioning: peripheral neurectomy in
which peripheral branch of nerve is avulsed.
• Cryotherapy: peripheral branches are subjected to
application of extreme cold by using cryoprobes
In this the nerve is not sectioned but destroyed
• Percutaneous procedure: Percutaneus procedures
involes mechanically or chemically damaging parts of
trigeminal groove
69

70. • Radiation therapy:
Gamma knife has been used which consists of multiple
rays of high energy photon concentrated on trigeminal
nerve root.
Can be used to destroy specific components of nerve
Source of radiation is Co 60
70

71.  Head neck and brain- bd chaurasia
 Gray’s anatomy
 Monheim’s local anesthesia and pain control in
dental practice
 Handbook of local anesthesia - malamed
 Peterson’s principles of oral & maxillofacial surgery
 Experimental trigeminal nerve injury g.R. Holland
crobm 1996 7: 237
71