trigeminal nerve anatomy

1. Trigeminal nerve

2. Contents
• Introduction
• Trigeminal Nuclei
• Functional Components
• Course & Distribution
• Trigeminal Ganglion
• Divisions of Trigeminal Nerve
• Clinical Examination of V Nerve
• Applied Anatomy
• Summary
• References

3. Introduction
• The largest cranial nerve
• It is mixed nerve ( sensory and motor )
• Sensory to  Skin of face
-Mucosa of cranial viscera
-Except base of tongue and pharynx
• Motor to  Muscles of Mastication
-Tensor villi palatini , Tensor tympany
-Anterior belly of digastric
-Mylohyoid

4. Trigeminal nuclei
• A cranial nerve nucleus is a collection of neurons (gray matter) in
the brain stem that is associated with one or more cranial nerves.
• Axons carrying information to and from the cranial nerves form
a synapse first at these nuclei.
• Lesions occurring at these nuclei can lead to effects resembling those
seen by the severing of nerve(s) they are associated with.

5. Sensory nuclei

7. Mesencephalic nucleus
• Cell body of Pseudo-unipolar neuron
• Relay proprioception from muscles of mastication,
• Extra ocular Muscles, Facial muscles.
• Situated in Midbrain just lateral to Aqueduct

8. Principal sensory nucleus
• Lies in Pons lateral to Motor nucleus
• Relays touch sensation

9. Spinal nucleus
• Extends from caudal end of principal sensory Nucleus in pons to 2nd
or 3rd spinal segment
• It relays Pain and Temperature

10. Motor nucleus
• Innervates muscles of mastication and tensor tympani and tensor
palatini
• Derived from first branchial arch.
• Located in pons medial to principle sensory nucleus.

13. FUNCTIONAL COMPONENTS
• Sensory Root
• Motor Root

14. SENSORY ROOT
• GENERAL SOMATIC AFFERENTS- Face, Scalp, Teeth, Gingiva, Oral,
Nasal, Cavities, Para nasal sinus, Conjunctiva and Cornea.

16. MOTOR ROOT

19. Course & distribution
• Both motor and sensory root are attached ventrally to junction of
pons and middle cerebellar peduncle
• Pass anteriorly in middle cranial fossa to lie below tentorium cerebelli
in cavum trigeminale, here motor root lies inferior to sensory root.

20. • Sensory root connected to posteromedial concave border of the
trigeminal ganglion.
• Convex anterolatateral margin of the ganglion gives attachment to the
3 divisions of the trigeminal nerve.

23. • Motor root turns further inferior with sensory component of V3 to
emerge out of foramen Ovale as Mandibular nerve.
• Ophthalmic and Maxillary division emerges through Superior orbital
fissure and foramen Rotundum respectively.

25. Ganglion

26. THE TRIGEMINAL GANGLION
• SEMILUNAR OR GASSERIAN GANGLION.
• Crescentic in shape with convexity
anterolaterally.
• Contains cell bodies of pseudo unipolar
neurons.
• LOCATION: lies in a bony fossa at apex of the
petrous temporal bone on floor of middle
cranial fossa

27. • COVERINGS: covered by dural pouch = MECKLES CAVE or CAVUM
TRIGEMINALE.
• lined by pia and arachnoid thus the ganglion is bathed in CSF.
• ARTERIAL SUPPLY: Ganglionic branches of Internal Carotid
Artery, middle meningeal artery and accessory meningeal artery.

28. RELATIONS
SUPERIORLY: *superior petrosal sinus
*free margin of tentorium cerebelli
INFERIORLY: *motor root
*greater petrosal nerve
*petrous apex
*foramen lacerum
MEDIALLY: *posterior part of lateral wall of cavernous sinus
*Internal Carotid Artery with its sympathetic plexus
LATERALLY: *uncus of temporal lobe
*middle meningeal artery and vein
*nervous spinosum

30. Divisions
1. Ophthalmic nerve
2. Maxillary nerve
3. Mandibular nerve

31. OPTHALMIC NERVE(V1)
• Smallest division.
• Sensory only
• Supplies : eyeballs, conjunctiva, lacrimal gland, mucosa of nose and
paranasal sinus, skin of forehead eyelid and nose

32. Course :

33. Lacrimal nerve
• Smallest
• Passes into orbit through lateral compartment
of the Superior orbital fissure outside the
tendinous ring.
• Receives communicating branch from
Trochlear nerve

34. • Receives branch from Zygomaticotemporal nerve branch of maxillary
• Sensory to lateral conjunctiva, Upper Lid, lacrimal gland
• Post synaptic parasympathetic fibres from pterygopalatine ganglion to
lacrimal gland (parasympathetic secretomotor).

36. FRONTAL NERVE
• Largest
• Enters orbit through lateral part of superior orbital fissure outside
tendinous ring
• Passes forward between roof of orbit and Levator Palpebral Superioris
Supratrochlear Nerve
• Divides midway into :
Supraorbital Nerve

38. SUPRATROCHLEAR NERVE SUPRAORBITAL NERVE
• Smaller nerve
• Medial branch
• Receives communication
branches from
infratrochlear nerve
• Curves around
superomedial margin of
orbit
• Larger nerve
• lateral branch
• Passes through
supraorbital notch
• Divides in medial and
lateral branches.

39. SUPRATROCHLEAR NERVE SUPRAORBITAL NERVE
• supplies: median
conjunctiva, Upper Lid and
lower part of forehead
• Lies between frontalis and
corrugator supercilliary
muscles
• Lies beneath frontalis muscle
• Supplies: conjunctiva,
scalp until vertex , mucous
membrane of frontal sinus

40. NASOCILLIARY NERVE
• Purely Sensory
• Passes through middle part of superior orbital fissure within the
tendonous ring .
• Runs along medial wall of orbit between Superior Oblique and Medial
Rectus
• Divides into Anterior Ethmoidal and External Nasal
• 5 branches in orbit.

41. 1. Short Cilliary Nerves: Fibers reaches eyeball and also contains
fibers from Cilliary Ganglion
2. Long Cilliary Nerves : 2 or 3in no. supply to Iris and Cornea.
3. Post Ethmoidal Nerve: passes through posterior ethmoidal foramen
to supply the Ethmoid and Sphenoid PNS.
4. Infratrochlear Nerve: appears on face above med angle the eye.
Supplies to skin of lacrimal sac and caruncle.

44. 5. Anterior Ethmoidal Nerve:
larger terminal branch
Course: anterior ethmoidal foramen and canal
into anterior cranial fossa on sup surf of cribriform plate
Through slit lat to crista galli into nasal cavity
Med internal nasal branch lat internal nasal branch
Supplies ant nasal septum supplies ant part lat nasal
cavity emerges as
external nasal nerve to
skin of ala,vestibule,and
tip of nose

45. MAXILLARY NERVE(V2)
• Second division of
trigeminal nerve
• Pure sensory
• Supplies derivatives of
maxillary process and
frontonasal process

46. Course:
Trigeminal ganglion-> Middle cranial fossa
Lateral wall of cavernous sinus
Foramen rotundum
Pterigopalatine fossa
In groove on posterior surface of maxilla
Through inferior orbital fissure into orbit as INFRA ORBITAL N
Through infraorbital foramen on face

49. Branches
• IN MIDDLE CRANIAL FOSSA:
• - Meningeal branch : Travels along the middle meningeal artery and
provides sensory innervation to cranial dura matter.

50. • IN PTERYGOPALATINE FOSSA:
• 1. Ganglionic branches-
• Arises as 2trunks.Trunks join to form single root within
pterygopalatine ganglion.
• Gives Orbital branches
• Palatine branches,
• Pharyngeal branches,
• Nasal branches

51. • Gives postganglionic secretomotor fibers to lacrimal gland via
zygomaticotemporal and lacrimal.

53. • Orbital branch: Supplies periosteum of orbit
• 3.Nasal branch: Supplies to mucosa of superior and inferior conchae,
posterior ethmiodal sinus and posterior portion of nasal septum. It
also includes Nasopalatine branch.

55. 4. Palatine branch: Arise as greater palatine (anterior) and lesser
palatine (middle and posterior)
• -Greater palatine nerve descends through pterygopalatine canal
from the ganglion and emerges from greater palatine foramen of hard
palate.
• -Middle palatine and posterior palatine emerges from lesser palatine
foramen and supply soft palate and tonsilar region respectively.

58. 5. Pharyngeal branch: It leaves the posterior part of pterygopalatine
ganglion and passes through the pharyngeal canal
• It is distributed to the mucous membrane of the nasal part of
pharynx, posterior to eustachian tube.

59. Posterior Superior Alveolar Nerve
• -It arises from the main trunk of maxillary nerve pterygopalatine
fossa just before the nerve enters the inferior orbital canal
• arises as 2 trunks.
• crosses the pterygoplatine fossa reaching infratemporal surface of
maxilla.
• - 1st trunk continues downwards on posterior surface of maxilla and
provide sensory innervation to buccal gingiva in maxillary molar
region and adjacent facial mucosal surface

60. • 2nd trunk enters maxila through PSA canal to travel to posterolateral
wall of maxillary sinus providing sensory innervation to sinus mucosa.

62. Zygomatic nerve
• It enters orbit through infra orbital fissure
. Zygomaticofacial nerve
-Appears on face through foramen in the zygomatic bone
-Supplies skin on prominence of cheek

63. Zygomaticotemporal nerve
-Appears in infratemporal region thru foramen in zygomatic
bone
-Supplies skin of temporal region after peircing temporal fascia 2
cm above zygoma
-Gives communicating branch to lacrimal N suppling parasymp.
Secretomotor fibres to lacrimal gland.
.

64. IN THE INFRAORBITAL CANAL
1.Middle superior alveolar nerve:
runs along lateral wall of maxilla
Participates in superior dental plexus
Supplies premolars.
2. Anterior superior alveolar nerve:
Runs in canal in ant wall of maxilla=canalii sinosus
#Dental branches # nasal branches
Joins sup dental plexus lat wallof inf meatus to
to supply canines opening of max sinus.

65. • 3. FACIAL BRANCHES:
• 1.Palpebral nerves-pierces Orbicularis Occuli and supplies skin of
lower lid.
• 2.Nasal branches-supplies skin of lat wall nose and mobile part of
septum.
• 3. Superior labial nerve- forms infraorbital plexus
• supplies skin and mm of upper lip, cheek and labial glands.

67. MANDIBULAR NERVE

68. MANDIBULAR NERVE

70. Branches
• Trunk (undivided)
• Nervous Spinosus
• Nerve to medial Pterygoid
• Anterior Division
• Massetric Nerve.
• Deep temporal Nerve.
• Nerve to lateral Pterygoid
• Buccal Nerve.
• Posterior Division
• Auriculo Temporal Nerve
• Inferior. Alveolar Nerve
• Lingual Nerve.

71. Branches from trunk
• Before dividing into anterior and posterior division it gives 2 branches during its 2-
3mm path
1.Nervous spinosus or Meningeal branch of Mandibular nerve
• It reenters cranial cavity through foramen spinosus along with middle meningial artery
• Supply Dura matter of middle cranial fossa and mastoid air sinus
2.Nerve to medial Pterygoid
• Supplies medial pterygoid
• Through Otic ganglion without interruption to
Tensor tympani
Tensor palatini

73. Branches from the anterior division
• The anterior division is significantly smaller than posterior.
• After dividing from the main trunk. It runs anteriorly and below the
lateral pterygoid muscle to over its upper border.

74. • After this the nerve is buccal nerve. reach its external surface of
muscle by either passing through two heads or winding
• 1.Nerve to lateral pterygoid: It enters the deep surface of the muscle.
It may arise as independent branch or may arise in common with
buccal nerve.

75. 2.Massetric nerve- Emerges at the upper border of the lateral pterygoid
just in front of TMJ. Passes laterally through mandibular notch along
with massetric vessels, and enters the deep surface of masseter, also
suppliesTMJ

76. 3.Buccal nerve-is the only sensory branch of ant div. travels betwn 2
heads of lat pterygoid and emerges in cheek at ant border of masseter.
Supplies skin and mucous membrane of cheek.
4.Deep temporal nerve-There are anterior and posterior deep temporal
nerves. Passes between skull, and enters deep surface of the
temporalis. Anterior is often a branch of buccal nerve and the posterior
may arise in common with massetric nerve.

77. Branches Of Posterior Division

78. 1.Auriculotemporal nerve-
Arises from 2 roots which run backwards and encircle the
middle meningeal artery and form single trunk
The trunk passes posterior to lateral pterygoid between neck
of mandible and sphenomandibular ligament superior to 1st
part of maxillary art.
Lies behind the TMJ close to the parotid
Ascends behind superficial temporal vessels and then in
temporal region divides into superficial temporal branches.

79. Branches Of Auriculotemporal Nerve
• Auricular branches- supply tragus, upper part of
aurical,roof of external auditory meatus, anterosuperior part
of tympanic membrane
• Superficial temporal branches-supply skin of temple
• It also supply sensory and secretomotor to parotid.
• Articular branches-supply the TMJ.

80. 2. Inferior alveolar nerve:
• Is mixed nerve
• Runs vertically downwards medial to lateral ptrygoid and
lateroposterior to lingual nerve
• Enters mandible through mandibular foramen

81. Branches
1.Mylohyoid: Supplies to mylohyoid muscle and anterior belly of
digastric. It is also sensory to skin on inferior and anterior
surface surfaces of mental protuberance. It may provide
sensory innervation to mandibular incisors. There is also
evidence that mylohyoid supply to mesial root of mandibular
frist molar.

82. 2.Branches to lower teeth and gums.
3.Mental nerve : It exits canal and divides into three branches innervating skin of
chin and skin and mucous membrane of the lower lip.
4.Incisive nerve : It remains within the canal and form plexus that innervates pulpal
tissue of first premolar canine and incisors through dental branches.

84. 3.Lingual nerve:
lies anterior to inferior alveolar n between lateral
pterygoid and tensor palatini
receives chorda tympani (SVA)
Emerges from inferior border of lateral pterygoid to lie between ramus and
medial pterygoid in peterygomandibular space
moves downwards and forwards deep to pterygomandibular raphe between
origins of supirior constrictor and mylohyoid
Reach to side of base of tongue 1 cm below and behind 3rd
molar just below
mucous membrane of lateral lingual sulcus

85. -Then proceeds anteriorly across the muscles of tongue ,looping
medially and downwards to submandibular duct to deep surface of
submandibular gland where it breaks into terminal branches
-Sensory to anterior 2/3 of tonge along with special sensation also
sensory to floor of mouth and gingiva on lingual side of mandible.

86. Branches of lingual nerve and its communications:
1.Chorda tympani
2.Communications with submandibular ganglion
3.Hypoglossal nerve

87. Ganglia Associated With The Trigeminal Nerve
1 .Cilliary Ganglion: connected with nasocilliary nerve by ganglionic
branches in orbit,
non synapsing
sensory for orbit
2.Pterygopalatine Ganglion: connected to maxillary nerve in
infratemporal fossa
sensory to orbital septum, orbicularis and nasal cavity, max sinus,
palate, nasopharynx.

88. 3. Otic Ganglion: between trunk of mandibular n and tensor palatini,
nerve to med pterygoid passes thru but does not synapse in the
ganglion.
4.Submandibular Ganglion: related to lingual n, rests on hypoglossus
supplies post gang. Parasym secretomotor fibres to submandibular and
sublingual gland.

89. CUTANEOUS DISTRIBUTION OF TRIGEMINAL
NERVE
Each half of face is supplied by 13 cutaneous Nerve
1motor and 12 sensory
Of 12 sensory : 11 are from trigeminal Nerve
1 is c2 greater auricular Nerve
Branches of trigeminal N
5 from ophthalmic: lacrimal
supraorbital
supratrocheal
infratrochlear
external nasal

90. 3 from maxillary N: infra orbital N
zygomaticofacial N
zygomaticotemporal N
3 from mandibular N: buccal N
auriculotemporal N
mental N

92. Examination of trigeminal nerve
1- Sensation Function
2- Motor Function
3- Corneal reflex
4- Test jaw jerk

93. • Sensation function
use sterile sharp item on forehead, cheek, and jaw
If any abnormality present we test the thermal sensation and light
touch

94. • Corneal reflex
• a clean piece of cotton wool and ask the patient to look away
gently touch the cornea with the cotton wool and the patient will
blink.

95. • Test jaw jerk
• Doctor finger on tip of jaw, grip patellar hammer halfway up
shaft and tap finger lightly usually nothing happens, or just a
slight closure.

96. Applied Anatomy
. Trigeminal Neuralgia – Tic Douloureux
• Sudden, usually unilateral severe, brief, stabbing lancinating,
recurring pain in the distribution of one or more branches of the
5th Nerve

97. 2. TRIGEMINAL NEUROPATHY
• sensory loss of face or weakness of the jaw muscles
• causes- sjogren syndrome
• herpes zoster, leprosy
• meningioma,schwanomma

98. 4. HERPES ZOSTER OPHTHALMICUS:
• Recurrent neuro-cutaneous infection In opth. division of
trigeminal dermatome, most freq. affecting nasociliary branch
• HHV3 / varicella zoster
• Gasserian ganglion
ophthalmic nerve
Supraorbital N. Infraorbital N.
Supratrochlear N.
Infratrochlear N.
Nasal N.

99. 5. Cavernous sinus syndrome
• Multiple cranial neuropathies
• Exophthalmos, ocular motor defects, sensory loss in V1 and / or V2.
• Pupils may be spared or involved.
causes: bacterial thrombophlebitis
actinomycosis
rhinocerebellar mucormycosis
aspergillosis
tolosa hunt syndrome
neoplasms
vascular lesions

100. 6.Gradenigos syndrome
• Gradenigo Syndrome (GS) is classically described as a clinical triad of
otitis media, facial pain and abducens palsy that is most commonly
developed from infection in the petrous temporal bone
• Infection is commonly caused by Streptococcus
pneumoniae, Haemophilus influenzae, Pseudomonas, and
Staphylococcus aureus

102. Prosthodontic significance
• Innervates major nerves in maxilla and mandible
• Nerve  damage during LA
• Nerve  Implant planning & Treatment

103. Summary
• Since Trigeminal nerve is mixed nerve, suplies mainly head and neck
region.
• Hence as a dentist one should know thoroughly about intracranial and
extracranial course and distribution of Trigeminal nerve, to diagnose
the pathologies associated with Trigeminal nerve and for appropriate
treatment.