The trigeminal nerve is a mixed nerve that is the largest of the cranial nerves. It has both sensory and motor functions. Sensory branches provide sensation to the face and motor branches innervate the muscles of mastication. The trigeminal nerve has three major divisions - ophthalmic, maxillary, and mandibular nerves. These divisions branch further to innervate specific regions of the face. The trigeminal ganglion contains the cell bodies of pseudounipolar neurons that relay sensory information from the face to the brainstem trigeminal nuclei.

1. THE TRIGEMINAL NERVE
BY Dr A K PANDEY
RESIDENT OPHTHAL

2. 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 veli palatini, Tensor tympani
-Anterior belly of digastric
-Mylohyoid

5. 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.

6. Sensory Nuclei – mesencephalic nucleus in
midbrain
- primary sensory nucleus in pons
- spinal nucleus in medulla and
spinal cord
Motor nucleus - one motor nucleus in pons

8. SENSORY NUCLEI
MESENCEPHALIC
NUCLEUS
 Cell body of
Pseudounipolar neuron
 Relay proprioception from
muscles of mastication,
Extra ocular Muscles, Facial
muscles.
 Situated in Midbrain just
latetral to Aqueduct

9. Principal sensory
nucleus
Lies in Pons lateral to
Motor nucleus
Relays touch sensation

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

11. 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 COMPONENT
Sensory root
Motor root

14. Sensory root

15. MOTOR ROOT

17. COURSE AND DISTRIBUTION
Both motor and sensory root are attached vertically
to junction of pons and middle cerebellar peduncle
with motor root lying ventromedially to sensory root
Pass anteriorly in middle cranial fossa to lie below
tentorium cerebelli in cavum trigeminale, here motor
root lies inferior to sensory root

18. Sensory root connected to posteromedial concave
border of the trigeminal ganglion
Convex anterolateral margin of the ganglion gives
attachment to the 3 div of trigeminal nerve.

19. 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.

21. TRIGEMINAL GANGLION
 SEMILUNAR OR GASSERIAN GANGLION.
 Cresentric in shape with convexity anterolaterally.
 Contains cell bodies of pseudounipolar neurons.
 LOCATION: lies in a bony fossa at apex of the petrous
temporal bone on floor of middle cranial fossa, just lateral to
posterior part of lateral wall of the cavernous sinus.

22.  COVERINGS: covered by dural pouch = MECKLES CAVE or
CAVUM TRIGEMINALE. cave 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.

24. RELATIONS
 SUPERIORLY: uncus and temporal lobe
 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: *middle meningeal artery and vein *nervous
spinosum

26. DIVISION OF TRIGEMINAL NERVE
1. Ophthalmic nerve
2. Maxillary nerve
3. Mandibular nerve

28. OPHTHALMIC NERVE
Smallest division.
Sensory only
Supplies : eyeballs, conjunctiva, lacrimal gland,
mucosa of nose and paranasal sinus, skin of forehead
eyelid and nose

29. COURSE

31. BRANCHES OF OPHTHALMIC NERVE
 Lacrimal nerve
 Frontal nerve
 Nasociliary nerve

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
(secretomotor), branch of maxillary
Sensory to lateral conjunctiva, Upper Lid, lacrimal
gland
Post synaptic parasympathetic fibers from
pterygopalatine ganglion to lacrimal gland i.e
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
 Divides midway into :
1. Supraorbital Nerve
2. Supratrochlear Nerve

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

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

40. NASOCILLIARY NERVE
 Purely Sensory
 Passes through middle part of superior
orbital fissure within the tendenious
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.  Short Clliary Nerves: Fibers reaches eyeball and also
contains fibers from Cilliary Ganglion
 Long Cilliary Nerves : 2 or 3 in no. supply to Iris and Cornea.
 Post Ethmoidal Nerve: passes through posterior ethmoidal
foramen to supply the Ethmoid and Sphenoid PNS.
 Infratrochlear Nerve: appears on face above medial angle of
the eye. Supplies to skin of lacrimal sac and caruncle

44. MAXILLARY NERVE
 Second division of
trigeminal nerve
 Pure sensory
 Supplies derivatives of
maxillary process and
frontonasal process

45. COURSE

46. After leaving foramen rotundum it moves anteriorly
in the uppermost part of pterygopalatine fossa.
As it passes through pterygopalatine fossa it also
gives branches to sphenopalatine ganglion, posterior
superior alveolar nerve and zygomatic branches

47. It then moves laterally and moves in a groove on
posterior surface of maxilla.
Then enters orbit through infra orbital fissure and
moves through infra orbital groove where it is called
as Infraorbital nerve and emerges on face from infra
orbital foramen

49. BRANCHES
 Meningeal branch – travels along the MMA and provides sensory innervation
to cranial dura matter
 IN PTERIGOPALATINE FOSSA:
1. Ganglionic branches-
Arises as 2 trunks. Trunks join to form single root within pterygopalatine
ganglion.
Gives Orital branches, Palatine branches, Pharyngeal branches,
Nasal branches
Gives postganglionic secretomotor fibers to lacrimal gland via
zygomaticotemporal and lacrimal

50. 2.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.
-It passes across roof of nasal cavity downwards and forwards lying
between mucosa and periosteum of nasal septum.
-Reaches to floor of nasal cavity and give branch to anterior part of
nasal septum and floor of nasal cavity.
-Enters Incisor canal and enters oral cavity through insicisor foramen
-It provides sensation to palatal mucosa of premaxilla region.

51. 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.
-Then moves anteriorly between mucoperiostem and hard
palate upto 1st premolar supplying sensory innervation to
palatal soft tissue and bone.
-Middle palatine and posterior palatine emerges from lesser
palatine foramen and supply soft palate and tonsilar region
respectively

52. 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

53. 6. POSTERIOR SUPERIOR ALVEOLAR NERVE
 It arises from the main trunk of maxillary nerve in the
petrygopalatine fossa just before the nerve enters the inferior
orbital canal
 Usually arises as 2 trunks.
 Passes downwards and 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

54. 2nd trunk enters maxilla through PSA canal to travel
to posterolateral wall of maxillary sinus providing
sensory innervation to sinus mucosa. Continuing
downwards this also provides sensory innervation to
alveoli, pulp of molar tooth.

56. Branches In Infraorbital canal
Middle superior alveolar nerve- runs along the lateral
wall of maxilla and participate in superior dental
plexus. Supplies premolars
Anterior superior alveolar nerve – runs in canal in
anterior wall of maxilla and gives dental and nasal
branches
Facial branches – palpebral , nasal and superior labial
nerve

58. MANDIBULAR NERVE
Formed by union of two trunks, the large sensory
trunk and small motor trunk
These two trunks pass through the foramen ovale
and unite to form one trunk
Motor root supplies the muscles of mastication, the
tensor tympani, the tensor veli palatine, mylohyoid,
anterior belly of digastric

59. APPLIED ANATOMY
Trigeminal neuralgia – sudden, usually unilateral
severe, brief stabbing, lancinating, recurring pain in
the distribution of one or more branches of the 5th
nerve
Trigeminal neuropathy- sensory loss of face or
weakness of the jaw muscles, caused due to Sjogren
syndrome, herpes zoster, leprosy, meningioma and
schwanomma
HZO – recurrent infection of ophthalmic div of
trigeminal dermatome most frequently affecting
nasociliary nerve

61.  Cavernous sinus syndrome- multiple cranial neuropathies,
exophthalmos, ocular motor defects, sensory loss in V1 and/or
V2 . Pupils may be spared
 Gradenigos syndrome- petrous bone osteitis due to otitis
media. Characterized by ipsilateral trigeminal nerve palsy,
retro orbital pain and ipsilateral sixth nerve palsy
 Neuroparalytic keratitis – due to involvement of trigeminal
nerve or section of its sensory root for neuralgia