trigeminal as known as dental nerve plays very important role in dentistry every dental student must have through knowledge about the nerve

1. Trigeminal Nerve
and
Periodontal Application
Presented by Dr. Aishvarya Hajare
1st year Postgraduate

2. Contents
›Introduction
›Anatomy
1. Origin
2. Course
3. Branches
›Periodontal implications
›Conclusion
›References

4. A neuron also known as a
neurone or nerve cell is an
electrically excitable cell
that processes and
transmits information
through electrical and
chemical signals.
A typical neuron consists
of a cell body (soma),
dendrites, and an axon.

5. Ganglion is a nerve cell
cluster or a group of nerve
cell bodies located in the
autonomic nervous system.
Ganglia house the cell bodies
of afferent nerves.
Nucleus is a cluster of
densely packed cell bodies of
neurons in the central nervous
system, located deep within
the cerebral hemispheres and
brainstem.

6. Introduction
 Trigeminal nerve is the fifth paired cranial nerve.
 The great sensory nerve of the head and face, and the motor nerve of the
muscles of mastication.
 The trigeminal nerve is associated with derivatives of the 1st pharyngeal
arch.

7. Anatomy
›Origin
The trigeminal nerve originates from three sensory nuclei
(mesencephalic, principal sensory, spinal nuclei of trigeminal
nerve) and one motor nucleus (motor nucleus of the trigeminal
nerve) extending from the midbrain to the medulla.

8. ›At the level of the pons, the sensory nuclei merge to form a sensory root. The
motor nucleus continues to form a motor root. These roots are analogous to the
dorsal and ventral roots of the spinal cord.
›In middle cranial fossa, the sensory root expands into the trigeminal ganglion.

9. Trigeminal ganglion
›The trigeminal ganglion is located lateral to the cavernous sinus, in meckel’s
cavity, on the anterior surface of the petrous portion of the temporal bone. This
depression is known as the trigeminal cave.
›The ganglia is flat and crescent shaped and measures approx. 1.0x 2.0cms.
›It is also known as the Gasserian ganglion & Semilunar ganglion.

10. ›The peripheral aspect of the trigeminal ganglion gives rise to 3 divisions:
›Ophthalmic (V1)
›Maxillary (V2)
›Mandibular (V3)

12. Course:
Enters the lateral wall of the cavernous sinus
Runs forward below the trochlear and oculomotor nerves.
Enters the orbit through the superior orbital fissure
Opthalmicbranch
Nasociliary nerve
Lacrimal nerve
Frontal nerve
External surface of the nose,
Anterior nasal cavity
Ethmoid sinuses , Sphenoidal sinus
Medial eyelids &Eyeball- cornea
Lateral part of the upper eyelids,
Conjuctiva
Lacrimal gland. Cranial dura
Frontal sinuses,
Upper eyelid
Bridge of the nose,
Forehead.

15. Ciliary ganglion Ciliary ganglion is a peripheral
parasympathetic ganglion placed
in the course of the occulomotor
nerve
It lies near the apex of the orbit
between the optic nerve, it has
parasympathetic, sensory and
sympathetic roots.
Parasympathetic root arises
from nerve to inferior oblique .
Sensory root- comes from
nasociliary nerve contains
sensory fibers for eyeball.
Sympathetic root is branch of
internal carotid plexus.

16. Maxillary nerve (V2)
›Wholly sensory
›Course: Traverse foramen rotundum
›post. wall of pterygopalatine fossa
›enters the inferior orbital fissure
›enter infra orbital canal
›emerges on face as infraorbital nerve

18. ›In the cranial cavity:
›Meningeal (to dura mater)
›In pterygopalatine fossa:
›Ganglionic- connected to PP ganglion; contain lacrimal secretomotor &
sensory fibres from orbital periosteum and mucosa of nose, palate and pharynx.
In the pterygopalatine fossa
›Zygomatic nerve ; it divides into zygomaticotemporal and zygomaticofacial
supply the cheek and temple.

19. Pterygopalatine ganglion

21. ›Pterygopalatine nerves supply the orbit, nose & palate. The nasopalatine nerve leaves nasal
cavity enters incisive foramen & supplies gingiva adjacent to maxillary central and lateral
incisors.
›The palatine branches are greater and lesser (palatal soft tissues and area around premolars)
›Posterior superior alveolar nerve ; supplies maxillary buccal gingiva of premolars and
molars. It enters bone supplies the distobuccal and lingual roots of 1st molar
›In the infraorbital canal:Supplies skin of nose, lower eyelid, and upper lip
› Middle- premolars and the mesiobuccal root of maxillary molar
› Anterior-the maxillary anterior teeth
›On face:
› inferior palpebral
› lateral nasal
› superior labial

22. Mandibular nerve(V3)

23. Origin
›The mandibular nerve is the largest division of the trigeminal
nerve. It is mixed nerve with two roots : a large sensory root & a
smaller motor root.
›The sensory root of the v3 originates at the inferior angle of the
trigeminal gangilion, whereas the motor root emerges from the
medulla oblongata.
›The two roots emerge from the cranium separately through the
foramen ovale , the motor root lying medial to the sensory. They
unite just outside the skull & form the main trunk of the third
division. The trunk remains undivided for only 2 to 3 mm before it
splits into small anterior and large posterior.

24. i. Branches from the undivided nerve
›A. Nervous spinosus – the nervous spinosus arises outside the
skull and then passes into the middle cranium fossa to supply the
dura and the mastoid cells.
›B. Nerve to the medial pterygoid muscle – a motor root passes to
innervate the medial pterygoid muscle. And the it gives off
branches to tensor veli palatini and tensor tymphani muscles.

25. ii Branches from the divided nerve
›Anterior division
›The anterior division is smaller than the posterior division. It
receives sensory and motor fibers that supply the muscles of
mastication, the skin and mucous membrane of the cheek and the
buccal gingivae and lower molars. It passes downward and
forward, where it divides
›1. Branch to the lateral pterygoid muscle.
›2. Branch to masseter
›3. Branch to temporal muscles
› a. Ant. Deep temporal nerve
› b. Post. Deep temporal nerve
›4. Buccal (long buccal ) nerve

26. ›Pterygoid nerve. It enters the medial side of the lateral pterygoid
muscle to provide its motor supply.
›2. Masseter nerve. Passes above the lateral pterygoid to
transverse the mandibular notch and enter the deep side of the
masseter muscle.
›3. Nerves to the temporal muscle
› a. Ant deep temporal nerve. This nerve passes upward &
crosses the infratemporal crest of the sphenoid bone and ends in
deep part of anterior portion of temporal muscle.
› b. Post deep temporal muscle. This nerve passes upward to the
deep part of temporal muscle.

27. ›4. Buccal nerve – usually the buccal nerve passes
downward, anteriorly and laterally between the two heads of
the lateral pterygoid muscle. At above the level of occlusal
plane of mand. 3rd and 2nd molar, it divides into several
branches that ramify the buccinator muscle.
›Sensory fibers are distributed to the skin of cheek, Buccal
gingiva of the mandibular molars and the mucobuccal fold of
that region.

28. ›B. Posterior division ; large posterior division is mainly sensory
but it carries some motor components.
 1. Auriculotemporal nerve – it arises by medial & lateral root.
These roots embrace the middle meningeal artery and unite
behind the artery just below the foramen spinosum. The
united nerve passes posteriorly deep to the external
pterygoid muscle , and then between the spenomandibular
ligament and the neck of the condyle of the mandible.
 It transverses the upper part of parotid gland & crosses the
posterior part of zygomatic arch. It passes with superficial
temporal artery in its upward course and divides into tragus
of the pinna of the external ear, to the scalp about the ear
and finally upward the skull.

29. a) Communication with the facial nerve, providing sensory
innervation to skin over motor innervation of facial nerve:
the zygomatic, buccal and mandibular
b) Communication with otic ganglion, providing sensory
secretomotor and vasomotor fibers to parotid gland
c) The anterior auricular branches supplying skin over helix
and tragus of ear
d) Branches to external auditory meatus, innervating the skin
over meatus and tymphanic membrane
e) Articular branches to the posterior portion of TMJ
f) Superficial temporal branches supplying the skin over
temporal region.

30. Lingual nerve
 At first it passes medially to the lateral pterygoid muscle
then as it descends, lies between the medial pterygoid
muscle and ramus of mandible in the pterygomandibular
space.
Chorda
tymphani
Lingual nerve
Inferior alveolar nerve

31. LINGUAL NERVE

33.  It runs anterior and medial to inferior alveolar nerve
whose path it parallels, then continues downward and
forward deep to ptyergomandibular raphe below the
superior constrictor .
 To reach the side of base of tongue, it lies just below
mucous membrane
 Proceeds anteriorly across the muscle of tongue, looping
downward and medial to submandibular duct to the
deep surface of sublingual gland, where it breaks up into
terminal branches.

34. Communication of the lingual nerve with the chorda
tympani branch of the facial nerve
 As the lingual
nerve passes
medially to the
external pterygoid
muscle, it is jointed
from behind by the
chorda tymphani
nerve.

36. ›Nerve fibers from the chorda tympani hitchhike
along the LN as special sensory fibers to provide
taste sensation from the anterior two-thirds of the
tongue and presynaptic parasympathetic fibers to
the submandibular ganglion.

37.  The secretory fibers of the chorda tymphani nerve
pass to the submandibular ganglion, where they
synpase.
 The secretory nerve fibers to the sublingual gland join
in a small branch from the submandibular ganglion to
rejoin the lingual nerve and pass with this nerve to the
sublingual gland
Chorda tymphani

38. Position of LN in Third Molar Region
 As the LN courses anteriorly to the retromolar region, it
follows the contours of the medial aspect of the mandible.
 Lingual nerve lies inferior & lingual to the crest of lingual
plate of mandible with a mean position of
2.28mm(±0.9)below the crest & 0.58mm (±0.9) medial to
crest - Kiesselbach & Chamberlain
 MRI study demonstrated that the nerve is located at a
mean distance of 2.53mm medial to and 2.75mm below
alveolar crest

39. Kiesselbach Miloro
Pogrel

41. Inferior alveolar nerve
 It passes downward on the medial side of the lateral pterygoid
muscle and the medial side of mandibular ramus.
 On the medial side of the ramus in the pterygomandibular
space, it enters the mandibular foramen.
 Within pterygomandibular space the inferior alveolar nerve
descends in the inferior alveolar canal and its distributed
throughout the body of mandible.

42.  It travels along with artery and vein anteriorly in the canal
as forward as mental foramen where the nerve divides
into terminal branches :
The incisive nerve and the mental nerve.

43.  The variations in the course of IAC are frequent. (Nortje´ et
al.1977; Berberi et al. 1994; Anil et al. 2003)
 Liu et al (2009) OPG classification of the course of the nerve
Linear spoon shaped elliptic arc turning curve

44. A. Gershenson H, Nathan E, Luchansky. Mental Foramen and Mental Nerve:
Changes with Age Acta Anatomica.1986;126:21-28

45. Anterior loop of IAN
›IAN courses inferiorly and anteriorly and then loops back to
emerge from the foramen.
Arzouman et al. Observations of the Anterior Loop of the Inferior Alveolar Canal.
International Journal of Oral & Maxillofacial Implants. May/Jun1993, Vol. 8 Issue 3, p1-11.

46. Loop dimensions – on radiographs (0-7.5mm), on cadaver specimens
(0-1mm), on panoramic radiographs (0.5-3.0mm)
Greenstein G et al The mental foramen and nerve: clinical and anatomical
factors related to dental implant placement: a literature review. J Periodontol.
2006 Dec;77(12):1933-43.

48. Mandibular foramen
›The mandibular foramen was located 4.12 mm below the occlusal
plane at the age of 3.
›By the age of 9, it had reached approximately the same level as
the occlusal plane.
›The foramen continued to move upward to 4.16 mm above the
occlusal plane in the adult group.
Hwang TJ et al. 1990 Age changes in location of mandibular foramen
Dental Association Of Republic Of China

49. Mental
nerve
Incisive
nerve

50.  The Mental nerve passes upward, backward & outward
to emerge from the mandible via the mental foramen
between & just below the apices of the premolar teeth.
 It immediately divides into three branches. Two of which
pass upward & forward to form an incisor plexus labial to
the teeth, supplying the gingiva.

51. ›From this plexus & the dental branches, fibers turn
downwards & then lingually to emerge on the lingual
surface of the mandible on the posterior aspect of
symphysis or opposite the premolar teeth; probably
communicating with the lingual or mylohyoid nerve.
›The third branch of mental nerve passes though the
intermingled fibers of depressor anguli oris & platysma to
supply the skin of lower lip & chin.

52. Position on mental foramen
SINGH, R. & SRIVASTAV, A. K. Study of position, shape, size and incidence of mental foramen
and accessory mental foramen in Indian adult human skulls. Int. J. Morphol., 28(4):1141-1146,
2010

53.  Incisive nerve- in mandibular canal, the inferior alveolar
nerve runs downward & forward, generally below the
apices of teeth until below the first & second premolars.
 The incisive branch continues forward in the bony canal
or in plexiform arrangement, giving off branches to the
first premolars, canine & incisors teeth & associated
labial gingiva.

54. Nerve to Mylohyoid
 It branches from the inferior alveolar
nerve before the latter’s entry into the
mandibular canal.
 It runs downward and forward in the
mylohyoid groove on the medial
surface of the ramus and along the
body of mandible to reach the
mylohyoid muscle and the anterior
belly of diagastric.

55. Otic ganglion
 Small, fusiform, between mandibular nerve and tensor tympani.
 Peripheral parasympathetic ganglion
 Connected functionally with glossopharyngeal nerve.

56. ›The preganglionic parasympathetic fibres originate in the inferior
salivatory ganglion of the glossopharyngeal nerve. They leave the
glossopharngeal nerve by its tympanic branch and then pass via the
tympanic plexus and the lesser petrosal nerve to the otic ganglion.

57. ›Here, the fibres synapse, and the postganglionic fibers pass by
communicating branches to the auriculotemporal nerve, which
conveys them to the parotid gland. They produce vasodilator and
secretomotor effects

58. Its sympathetic root is derived from the plexus on the middle meningeal
artery. It contains post-ganglionic fibers arising in the superior cervical
ganglion. The fibers pass through the ganglion without relay and reach the
parotid gland via the auriculotemporal nerve. They are vasomotor in
function.

59. Submandibular ganglion
 Small, fusiform, present on upper part of hyoglossus
 Superficial to deep part of submandibular Gland
 Connected functionally to facial nerve

61.  Sympathetic fibres from the external carotid (facial artery) plexus
pass through the submandibular ganglion.
 Preganglionic parasympathetic fibers from the superior
salivatory nucleus of the Pons, via the chorda tympani and
lingual nerve, which synapse at this ganglion.
 Postganglionic parasympathetic fibers are distributed to the
oral mucosa and the submandibular and sublingual salivary
glands. They are secretomotor to these glands.
 Branches: to submandibular and sublingual glands.

62. Applied Anatomy
›Trauma, tumors, aneurysms or meningeal infections will cause:
 Paralysis of muscles of mastication with deviation of mandible
towards the site of lesion.
 Loss of soft tactile, thermal or painful sensations on the face
 Loss of corneal reflex and sneezing reflex

63. ›Trigeminal Neuralgia :
› This is one of the most common clinical problems of the
trigeminal nerve.
› It is characterized by periods of severe shooting pain in the area
of supply of the trigeminal nerve.
›The pain localizes to the side of the face, and involves the areas
of innervation of one or more of the divisions of CN V - usually
the maxillary or mandibular divisions.
›The origin of the pain is unknown.

64. ›Herpes Zoster :
› As with other sensory ganglia, the trigeminal ganglion is vulnerable to
this infection.
› This viral infection results in considerable pain and ulceration of the
skin and mucous membranes supplied by the affected fibres. The
ophthalmic division is most frequently affected.

65. ›Periodontal ligament and intraosseous anesthetic injection techniques:
alternatives to mandibular nerve blocks.
›The PDL injection and the IO injection are effective anesthetic techniques
for managing nerve block failures and for providing localized anesthesia in
the mandible.
J Am Dent Assoc. 2011 Sep;142 Suppl 3:13S-8S.

66. THE PERIODONTAL LIGAMENT ANESTHETIC INJECTION

67. THE INTRAOSSEOUS ANESTHETIC INJECTION

68. Applied anatomy of implant
›Posterior superior alveolar nerve may get injured during sinus
augmentation with lateral approach, infraorbital nerve may get
paresthesized during fixation of implant when inserted through
graft and into structure.
›Subperiosteal implants designed for an atrophic maxilla should
not extend into the site of infraorbital nerve and vessels.

69. ›The potential use of reconstruction techniques on
computed tomograhic scans &MRI may increase clincians
ability to locate inferior dental canal precisely within the jaw
bone.
›In excessively resorbed the mental foramen within its
content of mental nerve and vessels can be found on the
crest of ridge.
›Nerve to mylohyoid is closely related to the ramus of
mandible, surgical intervention in this area may lead to
injury of important motor nerve which is mylohyoid

70. Conclusion
›Trigeminal nerve also known as dental nerve sensory supply the head
and neck region & motor supply to masticatory muscles thus through
knowledge about its course and branches is essential.

71. References
 Gray’s anatomy 41st edition
 B.D. chaurasia vol 3 anatomy of head neck and face
 Neelima Mallik’s Textbook Of Oral And Maxillofacial Surgery
 Malamed 6th edition Texbook of Local anaesthesia
 Moore PA, Cuddy MA, Cooke MR, Sokolowski CJ. Periodontal ligament
and intraosseous anesthetic injection techniques: alternatives to
mandibular nerve blocks. J Am Dent Assoc. 2011 Sep;142 Suppl 3:13S-
18S
 Arzouman et al. Observations of the Anterior Loop of the Inferior
Alveolar Canal. International Journal of Oral & Maxillofacial Implants.
May/Jun1993, Vol. 8 Issue 3, p1-11

72. References cont.
 Greenstein G et al The mental foramen and nerve:
clinical and anatomical factors related to dental implant
placement: a literature review. J Periodontol. 2006
Dec;77(12):1933-43
 A. Gershenson H, Nathan E, Luchansky. Mental
Foramen and Mental Nerve: Changes with Age Act
Anatomica. 1986;126:21-28
 Hwang TJ et al. 1990 Age changes in location of
mandibular foramen Dental Association Of Republic Of
China