Trigeminal nerve/prosthodontic courses

18/07/08
Trigeminal nerve
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

contents
 Introduction
 Formation
 Course
 Divisions of trigeminal nerve
1. Opthalmic nerve
a.lacrimal nerve
b.frontal nerve
c.nasocilliary nerve

 Maxillary division
1. Branches to middle cranial fossa
2. Branches in pterygopalatine fossa
a. zygomatic
b. pterygopalatine
c. post .superior alveolar branches
d. branches in the infraorbital groove
and canal
3) Terminal branches of max division of face

 Mandibular division
1. Branches from undivided nerve
2. Branches from divided nerve
a. Anterior division
b. Posterior division
 Autonic gangia associated with the
mandibular division of T N
a. Submandibular ganglion
b. Otic ganglion
 Applied anatomy
 conclusion www.indiandentalacademy.com

INTRODUCTION
 There are 12 pairs of cranial nerves.
 Which originate from different parts of brain like
forebrain, midbrain, pons, and medulla.
 Each cranial nerve has name and no as follows:

FORMATION
 Trigeminal nerve is largest cranial nerve composed of small
motor root and considerably large sensory root.
 It has four nuclei:
 1. MAIN SENSORY NUCLEUS:
 Lies in posterior part of pons lateral to motor nucleus. It is
continuous below with spinal nucleus.
Function:- Touch, pressure from skin and mucous
membrane of facial region.
 2. SPINAL NUCLEUS:
It extends inferiorly through the whole length of medulla
oblongata and into upper part of spinal; cord up to second
cervical segment.
Function:- Pain and temperature from skin of face and
mucous membrane.
1.

 3. MOTOR NUCLEUS:-
It is situated in pons medial to sensory nucleus.
Function:- Movement of mandible.
 4. MESENCEPHALIC NUCLEUS:-
It is composed of unipolar cells situated in lateral part of
gray matter around the cerebral aqueduct. It extends
inferiorly into pons
Function:- It serves as afferent station that receives
proprioception impulses from temporomandibular joint,
periodontal ligaments, muscles of mastication and facial
and extra ocular muscles

Mesencephalic nucleus
Spinal
nucleus

COURSE:-

 It leaves anterior part of pons as small motor root
and a large sensory root. The sensory root arises
from mid-lateral surface of pons passes forward
out of posterior cranial fossa to rest on petrous
temporal bone where it expands to form cresent
shaped trigeminal ganglion which is situated in
Meckels cave.
 Small motor root attached to the pons
superomedial to sensory root arises from cells of
masticator nucleus. It passes under ganglion
from its medial to lateral side and joins the
mandibular nerve at foramen oval

Internal carotid art.
Ophthalmic nerve
. Trigeminal ganglion
Motor root

 Within trigeminal ganglion sensory
pseudounipolar nerve cells forms one process
which then divides into central and peripheral
processes.
 Central processes leave the semilunar ganglion
and pass back and enter pons where they divide
into ascending and descending fibers.
 Ascending fibers terminates into upper sensory
nucleus in pons lateral to motor nucleus.
Ascending fiber conveys light touch, tactile
discrimination, sense of position and passive
movement.

 Upper sensory nucleus gives rise to dorsal
trigeminothalamic tract.
 Spinal nucleus of trigeminal nerve gives
rise to ventral trigeminothalamic tract.
Fibers from vetral trigemonothalemic
tracts cross to opposite side and ascend to
thalamus. From thalamus this fibers
continues to cerebral cortex.
 These fibers convey pain and temperature
from entire trigeminal area.

 Mesencephalic root of trigeminal nerve:-
 - It consists of afferent fibers that accompany the
fibers of motor root. These fibers enter the pons
from peripheral distribution of mandibular nerve
and ascend to mesencephalic nucleus.
 It serves as afferent station that receives
proprioception impulses from TMJ, periodontal
ligaments, muscles of mastication, hard palate.
 These fibers are concerned with perfect
synchronization in controlling the biting force of
jaws.

Divisions of trigeminal nerve
 Three large nerves proceed through
convex part of semilunar ganglion.
1. Ophthalmic nerve. [V1]
2. Maxillary nerve [V2]
3. Mandibular nerve [V3]

 OPTHALMIC NERVE:-
 It is first division of trigeminal nerve. It
is smallest of three divisions and sensory in
nature.
 It leaves anteromedial part of ganglion and
passes forward in lateral wall of cavernous
sinus. Just before entering orbit via superior
orbital fissure it divides into its three main
branches:-
 Lacrimal
 Frontal
 Nasocilliary

 LACRIMAL NERVE:-
It is smallest of three branches. It passes into
orbit at lateral angle of superior orbital fissure
then proceeds in anterolaterally to reach lacrimal
gland. Here it supplies sensory fibers to gland
and adjacent conjunctiva.
 FRONTAL NERVE:-
 It is the largest of three branches. It enter orbit
through superior orbital fissure at about middle of
orbit.

 Frontal nerve divides into two branches:-
 Supra orbital
 Supratrochlear
 Supraorbital nerve : -
Largest branch of frontal nerve. It leaves the
orbit through supraorbital foramen.
 Supratrochlear nerve: -
Smallest branch of frontal nerve. It passes
towards upper medial angle of orbit. Here it
pierces the fascia of upper eyelid to supply skin of
upper eyelid and lower medial portion of
forehead.

NASOCILLIARY NERVE:
 Third main branch of ophthalmic division.
It enter orbit through superior orbital
fissure
 Branches of Nasocilliary nerve:-
 Long cilliary nerve
 Nerve to cilliary ganglion
 Infratrochlear nerve
 Anterior ethmoidal nerve
 Posterior ethmoidal nerve

Branches of ophthalmic division with area of distribution
DIVISION BRANCHES AREA OF DISTRIBUTION
Frontal nerve Supra orbital nerve Forehead, conjunctiva, skin of
upper eyelid, frontal sinus
Supra Trochlear nerve Skin of upper eyelid, lower
medial portion of forehead
Naso-cilliary
nerve
Long cilliary nerve sclera
Nerve to cilliary ganglion Eye ball
Infratrochlear nerve Conjunctiva, lacrimal sac,
medial ends of eyelids &
upper half of eternal nose
Anterior ethmoidal nerve Middle & anterior ethmoidal
air sinuses, medial internal
nasal, lateral internal nasal,
external nasal
Posterior ethmoidal nerve Sphenoidal & posterior
ethmoidal air sinuses
Lacrimal nerve Nerve to lacrimal gland Lacrimal gland
Nerve to eyelid Lateral skin of upper
eyelid

Autonomic ganglion associated with
ophthalmic division
 Cilliary ganglion:- It is located near apex of
orbit between optic nerve & origin of lateral
rectus muscle.
Roots:-
 Sensory roots:- It comes from naso cilliary
nerve. It carries sensory fibers from eye ball.
 Motor root:- arises from occulomotor nerve. It
carries preganglionic fibers from Edinger- westfal
nucleus. Post ganglionic fibers pass through short
cilliary nerve and supply to cilliaris and sphincture
pupillae muscles.

 Sympathetic root:- derived from branch of
internal carotid plexus carries post ganglionic
fibers of superior cervical ganglion to supply
blood vessels of eyeball and dilator pupillae .

MAXILLARY NERVE
 It is second division of trigeminal nerve, is
entirely sensory.
 It originates in middle of semilunar ganglion runs
forward in lateral wall of cavernous sinus below
ophthalmic nerve and leaves middle cranial fossa
by passing through foramen rotundum and enters
the pterygopalatine fossa where it gives posterior
superior alveolar nerve and zygomatic nerve
branches. Beyond which it is continued as
infraorbital nerve.
 It enters the inferior orbital fissure to pass into
orbital cavity.

In its course from semilunar ganglion
maxillary nerve gives of branches in four
regions:-
 In middle cranial fossa
 In pterygopalatine fossa
Ganglionic branches
Zygomatic nerve
posterior superior alveolar nerve
 In infraorbital groove and canal
Middle superior alveolar nerve
Anterior superior alveolar nerve
 On face

 Branches in middle cranial fossa:-
Meningeal branch: - supplies the dura matter of cranial
fossa.
 Branches in pterygopalatine fossa:-
 A] Ganglionic branches:-
Ganglionic branches are actually branches of maxillary
nerve.
 1] Orbital branches:-
Pass through inferior orbital fissure and supply the
periosteum of orbit and orbitalis muscle.
 2] Palatine branches:-
- Greater or anterior palatine nerve descends through greater
palatine canal supplies hard palate and lateral wall of nose.
- Lesser or middle palatine nerves supply soft palate and
tonsils.

 3] Nasal Branches:-
- enter nasal cavity through sphenopalatine
foramen.
- Lateral posterior superior nasal nerve and
medial posterior superior nasal nerve supplied
thee roof of nose and nasal septum. Largest of
these nerves are known as naso palatine nerve
which descends up to anterior part of hard palate
through incisive foramen.
 4] Pharyngeal branch:-
Passes through palatovaginal canal and supplies
part of nasopharynx behind auditory tube.

B] Zygomatic nerve:-
It enters orbit through inferior orbital fissure and
divides into zygomaticofacial and
zygomaticotemporal nerves.
1] Zygomaticofacial nerve: - supplies skin on
prominence of cheek.
2] Zygomaticotemporal nerves: - supplies
innervations to the skin on side of forehead.
 Before leaving orbit zygomatic nerve sends a
branch that communicates with lacrimal nerve of
ophthalmic division. This branch carries secretory
fibers from sphenopalatine ganglion to the
lacrimal gland. www.indiandentalacademy.com

Posterior superior alveolar nerve:-
 Two- three branches leave maxillary division
before it enters inferior orbital fissure. They
pass downward and continue on surface of
maxilla.
 When two trunks are present one remains
external to bone continuing downwards on
posterior surface of maxilla to provide
sensory innervations -buccal gingiva in
maxillary region and adjacent facial mucosal
surfaces.
 Where as the other branch -sensory
innervations to mucous membrane of sinus.

 Continuing downwards this second
branch of PSA provides sensory
innervations.
- alveoli,
-periodontal ligaments,
- pulpal tissues of maxillary 3rd, 2nd
and 1st molars with exception of
mesiobuccal root of 1st molar

Branches in infraorbital canal:-
 Within infraorbital canal the maxillary
division gives two branches of significance
in dentistry.
 Middle superior alveolar nerve
 Anterior superior alveolar nerve
Middle superior alveolar nerve:-
 - It passes along the lateral wall of
maxillary sinus joins with superior dental
plexus and supplies premolar teeth.

Anterior superior alveolar nerve
 - It supplies sensory innervations to mucous
membrane of anterior part of maxillary sinus as
well as maxillary central, lateral, incisors,
cuspids and their respective gingivae.
Branches on face (Terminal branches):-
 Infra orbital emerges through infra orbital
foramen onto face to divide into:
1. Inferior palpebral-skin of lower eyelid,surfaces of
conjuctiva
2. Lateral nasal-skin on lateral aspect of nose
3. Superior nasal.-skin and mm of of upper lip,
sometimes adjacent gigiva of 2nd
premolar teeth.

FUNCTIONS
 The maxillary nerve transmits sensory
fibers from the skin of face between lower
eyelid and the mouth from the nasal cavity
and sinuses and from the maxillary teeth.

MANDIBULAR NERVE

 Branches from main trunk:-
Nerve to medial pterygoid
Meningeal branch [nervous spinosm]
 From anterior division:-
Buccal nerve
Deep temporal nerve
Massetric nerve
Nerve to lateral pterygoid

 Branches from posterior division:-
Auriculotemporal nerve
Inferior alveolar nerve
Lingual nerve

 It is largest of three divisions of trigeminal nerve.
It is mixed nerve and consist of large sensory and
small motor root arises directly from trigeminal
ganglion and the motor root arises directly from
pons.
 From middle cranial fossa both root emerges
through foramen ovale. Just before foramen
ovale both roots join together and form the
mandibular nerve trunk. After a short course the
trunk divides into small anterior divisions and
large posterior division.

Branches from main trunk:-
Meningeal branch [nervous spinosm]:-
 Enters skull through foramen spinosm
along with middle meningeal artery and
supplies dura matter of middle cranial
fossa.
Nerve to medial pterygoid:-
 It supplies medial pterygoid and tensor
palatini, tensor tympani.

 From anterior division:-
 It gives three motor and one sensory branch.
 Buccal nerve:-
 It is only sensory branch of anterior division. It
emerges between two heads of lateral pterygoid
and appears on cheek beneath the anterior
border of masseter.
 Buccal nerve supplies sensory fibers to gingiva of
mandibular molars, mucous membrane of lower
part of buccal vestibule and mucous membrane of
cheek related to buccinator muscle.

 Deep temporal nerve: - supplies deep
part of temporalis muscle.
 Massetric nerve: - emerges through
mandibular notch and enters deep side of
masseter.
 Nerve to lateral pterygoid:- supplies
lateral pterygoid muscle.

Branches from posterior division
They are mainly sensory.
Auriculotemporal nerve
Inferior alveolar nerve
Lingual nerve

Auriculotemporal nerve:-
 It usually arises by two roots which encircles
middle meningeal artery, then these roots unites
to form single trunk below the foramen spinosm.
United nerve passes deep to lateral pterygoid
muscle and neck of condyle.
 It traverses upper part of parotid gland and then
crosses the posterior part of zygomatic arch.
Finally it enters temple where it divides into
superficial temporal branches.

 It receives communicating branches from otic
ganglion which convey post ganglionic
secretomotor fibers to parotid gland
 Branches:-
Auricular branch: -
 supply to tragus, anterior wall of external
acoustic meatus
Superficial temporal branches: -
 supplies skin of temple.
Articular branches:-
 supplies temporomandibular joint

 2] Inferior alveolar nerve:-
Largest branch of mandibular division. It descends medial
to lateral pterygoid then to region between
sphenomandibular ligament and medial surface of
mandibular ramus where it enters the mandibular foramen.
 It finally divides into incisive and mental nerves
 1] From mandibular canal:- it supplies molar, premolar
teeth and adjacent gingival.
 2] Incisive nerve:- supplies canine, incisors teeth and
adjacent gingival.
 3] Myelohyoid nerve:- it is motor nerve arises from
inferior alveolar nerve before it enters mandibular foramen.
It supplies mylohyoid and anterior belly of diagastric
muscle
 4) mental nerve:- leaves body of mandible and supplies to
the chin, lower lip

3] Lingual nerve:-
 It passes downwards medial to lateral pterygoid
muscle. It runs anterior and medial to inferior
alveolar nerve. it then continues downwards and
forwards deep to pterygomandibular raphe and
below attachment of superior constrictor of
pharynx to reach side of base of tongue slightly
below and behind mandibular 3rd molar.
 It communicates with chorda tympani nerve and
with submandibular ganglion on hyoglossus.
Through this communication it conveys
secretomotor fibers to submandibular and
sublingual gland

Otic ganglion:-
 Topographically it is related to mandibular nerve but
functionally related to glossopharyngeal nerve.
 Situation:- it is situated in infratemporal fossa just beneath
the foramen ovale.
Roots:-
 Parasympathetic root: - it is derived from lesser petrosal
nerve.
 Preganglionic fibers from inferior r salivatory nucleus are
passed through glossopharyngeal nerve. Its tympanic
branch and lesser petrosal nerve to reach the ganglion.
 The post ganglionic fibers reach parotid gland through
auriculotemporal nerve.
 Sympathetic root: - derived from a nerve plexus around
middle meningeal artery. And conveys post ganglionic fibers
from superior cervical ganglion.www.indiandentalacademy.com

APPLIED ANATOMY:-
 Trigeminal neuralgia
 Definition - as a sudden, usually unilateral,
severe, brief, stabbing, lancinating,
recurring pain in distribution of one or
more branches of 5th
cranial nerve
 John Locke 1677
 Nicholaus Andre 1756- Tic doloureux
 John Fothergills 1773- fothergills disease

ETIOLOGY:-
 Unknown
 Dental – westrum and black , loss of teeth and
degeneration of nerves
 Infections
 Multiple sclerosis
 Post traumatic neuralgia
 Intracranial tumors
 Intracranial vascular abnormalities
 Viral etiology

General characteristics:-
Incidence : 4 in 100,000 persons
Age :5th
or 6th
decade
sex : female predisposition (58%)
Affliction for sides: for right side (60%)
Division : v3 > v2 and v1 rarely

Clinical characteristics:-
 Manifests as a sudden, unilateral,
intermittent, paroxymal, sharp, shooting,
lancinating, shock like pain , elicited by
slight touching of superficial trigger points
which radiates from that point, across the
distribution of one or more branches of the
trigeminal nerve.

 Pain confined to one part of one division
 Pain is of short duration and last for few
sec, but may reccur with variable
frequency
 During attack the patient grimaces with
pain, clutches with his hands over the
affected side of the face, stopping all the
activities and holds or rubs the face male
patients avoid shaving , the oral hygiene
is poor

 Paroxyms occur in cycles
 Extreme cases– frozen or mask like
appearance
 Presence of an intraoral and extraoral
triggerpoints provocable by by obvious
stimuli
 Stimuli – touching face, chewing ,speaking
or smiling, brushing, shaving or even
washing face etc.

 Location of trigger points
 In v2- on skin of upper lip, ala of nasi or
cheek or on the upper gums
 In v3- lower lip, teeth gums of lower
jaw,tongue
 In v1– supraorbital ridge
  attack do not occur during sleep
 Pts undergo teeth extractions pain mimics

Diagnosis:-
Well taken history
MRI SCANNING
CT SCAN
Diagnostic Injections Of Local Anesthesia

 TREATMENT
 Medical care:-
 Carbamazepin
 Gabapentine
 Lamotrigine
 Phenytoin
 Baclofen
 Surgical care:-
 alcohol block
 cryotherapy
 Micro vascular decompression

 Pain from diseased mandibular teeth or
carcinoma of tongue is referred along the
distribution of auriculotemporal nerve to ear and
temporal region.
 A lesion of trigeminal nerve cause anesthesia of
anterior half of scalp, face cornea, conjunctiva,
mucosa of nose, mouth, anterior two third of
tongue.
 If lingual nerve is involved in anterior to junction
with chorda tympani loss of taste in half of
anterior part of tongue occurs. Extraction of mal
placed wisdom tooth have higher incidence of
lingual nerve injury

 Damage to the inferior alveolar nerve as the
result of root canal therapy
 mechanical trauma from overinstrumentation into
the inferior alveolar canal;
 the pressure phenomenon from the presence of
the endodontic point or sealant within the inferior
alveolar canal
 the neurotoxic effect from the medicaments used
to clean the canal or that are in the sealant.
(M. Anthony Pogrel, jada july 2008)

 Endodontic overfilling involving the mandibular
canal may cause an injury of the inferior alveolar
nerve (IAN) resulting in disabling sensory
disturbances such as pain, dysesthesia,
paresthesia, hypoesthesia, or anesthesia.
 sagittal osteotomy was used to remove the
endodontic paste and to perform nerve
decompression. All the patients experienced
immediate relief of dysesthesia and paresthesia.
(Paolo Scolozzi, et al Oral Surg Oral Med Oral
Pathol Oral Radiol Endod 2004;97:625-31)

CONCLUSION
CONCLUSION

references
 Grays anatomy 4th
edition
 Monheims –Richard Bennett
 Local anesthetics- Stanley Malamed
 Oral and maxillofacial surgery- Neelima Anil Mallik
 Grants anatomy
 Colour atlas of human anatomy
 Human anatomy – B.D. Chaurasia
 Hand book of neurosurgery, mark green berg,
3rd edition

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