trigeminal nerve

1. Course of trigeminal nerve & its
importance in OMFS
Anchal Mehra
PG OMFS

2. Contents
• Introduction
• Anatomy
• Clinical examination
• Clinical importance
• Nerve injury
• Related pathology
• Conclusion
• References

3. INTRODUCTION
It’s motor to the muscles of 1st
branchial arch & several small muscles.
It’s sensory to the head & face region.

4. • At the level of the pons,anterolaterally, the
sensory nuclei merge to form a sensory root.
• The motor nucleus continues to form a motor root.
• Nerve leaves the anterior aspect of the pons as a
small motor root and a large sensory root, and it
passes forward, out of the posterior cranial fossa,
to reach the apex of the petrous part of the
temporal bone in the middle cranial fossa.

5. Functional component
• Special visceral efferent (SVE) fibers- arise from
motor nucleus of CN5, & supply muscles of
mastication,mylohyoid,anterior belly of
diagastric,tensor veli palatini,tensor tympani.
• General somatic afferent (GSA)- they carry
proprioceptive sensation from
muscles of mastication, TMJ,
teeth & terminate in the motor
nucleus.
Exteroceptive sensation (i.e,
pain.touch & temperature ), from
skin of the head & face,,nasal
cavity,meninges etc. & terminate in
the principal nucleus of CN5

6. Sensory root
GSA- face,scalp,teeth,gingiva,oral & nasal
cavities, para nasal sinus, conjunctiva, cornea.

7. Motor root
CNS
Motor nucleus
Motor root
Mandibular nerve
Muscles of mastication, mylohyoid,tensor
tympani,tensor veli palatini.

8. Trigeminal ganglion
1. Largest sensory ganglion in body. Cresent &
flat in shape.
2. Approximately, 1 x 2 cms, covexity face
anteriorly & downward.
3. Medially, it is in relation with the internal carotid
artery and the posterior part of the cavernous
sinus.
2. Lies under meningeal dura , lateral to the
cavernous sinus in meckle’s cave on
the apex of petrous temporal bone in
middle cranial fossa.

9. Divisions
• The peripheral aspect of the trigeminal ganglion
gives rise to 3 divisions:
• ophthalmic (V1),
• maxillary (V2) and
• mandibular (V3).

10. OPHTHALMIC NERVE
• Purely sensory.
• It runs forward in the lateral wall of the cavernous
sinus in the middle cranial fossa and divides into
three branches, which enter the orbital cavity through
the superior orbital fissure.

11. Branches
Tentorial
branch
Frontal
Supraorbital
Supratrochlear
Lacrimal
Nasocilliary

12. Frontal nerve
• After emerging from the ophthalmic nerve , it
enters the superior part of the superior orbital
fissure.

13. Frontal nerve
• Runs forward between the
levator palpebrae superioris
muscle and periosteum of the
ROOF of the orbit.
• About midway across the
orbit, it divides into the
supraorbital and
supratrochlear nerves.

14. supraorbital
• Continues anteriorly to
supra orbital foramen.
• Supplies frontal sinus
• Ascends superiorly along
the scalp.
• Supply skin of forehead &
scalp as far as lambdoid
suture.
supratrochlear
• Supplies conjunctiva & skin
of the medial aspect of
upper eye lid.
• Supplies the frontal sinus
• Skin of the forehead &
scalp.

15. Lacrimal nerve
• In the orbit it travels on
the superior border of the
lateral rectus with the
lacrimal artery.
• It receives a
communication from the
zygomatic nerve through
which secretory fibres
pass to the lacrimal
gland.
The lacrimal nerve then enters the
lacrimal gland and gives branches
to the conjunctiva and the skin of
the lateral part of upper eyelid.

16. Nasocilliary nerve
• Runs along the medial
wall of the orbit, within
the tendinous ring, giving
branches to nasal cavity
& ending in the skin at
the root of the nose.

17. Branches
1. Sensory root to the ciliary
ganglion.
2. Long & short ciliary
nerves
3. Posterior ethmoidal nerve
4. Anterior ethmoidal nerve
5. Infratrochlear nerve

18. Posterior ethamoidal
• Travels deep to the
superior oblique m.
to pass through the
posterior ethmoid
foramen.
• Supplies the
sphenoid sinus and
the posterior
ethmoid sinus.
Anterior ethamoidal
• Enters the anterior
ethmoid foramen
and travels through
the canal to enter the
anterior cranial fossa
• Supplies the anterior
and middle ethmoid
sinus before entering
and supplying the
nasal cavity
• Terminates as the
external & internal
nasal n. on the face.
Infratrochlear
• Passes anteriorly on
the superior border
of the medial rectus
m.
• Passes inferior to the
trochlea toward the
medial angle of the
eye.
• Supplies the skin of
the eyelids and
bridge of the nose,
the conjunctiva.

19. Maxillary nerve

21. Branches within mid cranial fossa
• Meningeal branch- supplies the meninges.

22. BRANCHES WITHIN THE
PTERYGOPALATINE FOSSA
Posterior
superior alveolar
Zygomatic
Ganglionic
branches
Infraorbital

23. • Zygomatic -Passes through the inferior orbital fissure
to enter the orbit.
• Passes on the lateral wall of the orbit and branches
into the zygomaticotemporal and zygomaticofacial
branches
• The zygomaticotemporal branch gives
parasympathetic secretomotor fibers to the lacrimal
gland via the lacrimal nerve. Supply the skin on side
of the forehead.

24. • Zygomaticofacial nerve- traverse
inferolaterally in the orbit , emerging through
a zygomaticofacial foramen in zygomtic bone,
perforating orbicularis oculi. supply the skin
on the prominence of the cheek.

25. • PSA- Passes through the pterygomaxillary
fissure in the infratemporal fossa, it passes on
the posterior surface of the maxilla along the
region of the maxillary tuberosity.
• Supplies maxillary sinus, 1st molar except
mesiobuccal root, gingiva & mucosa of the
same.

26. • Ganglionic branches- two short nerves that suspend
the pterygopalatine ganglion in the pterygopalatine
fossa.
• They also contain postganglionic parasympathetic
fibers from the pterygopalatine ganglion & from the
zygomaticotemporal nerve, that are going to the
lacrimal gland.

27. Branches of pterygopalatine nerve-
• supply 4 areas – orbit, nose,palate, pharynx.
• Through inferior orbital fissure, some branches
goes to the orbit.
• Supply sphenoidal sinus mucosa,ethmoidal sinus
mucosa & orbital periosteum.
Orbital part

28. Nasal branch
• From sphenoapalatine foramen-gives nasal
branch, also known as posterior superior nasal
branch.
• This nasal branch has 2 branches- posterior
superior medial & post. Sup. Lateral.
• Post. Sup. Medial comes to the palate through
the incisive canal & then from both the sides into
incisive foramen as nasopalatine nerve, supplying
the sensation to palatal mucosa in premaxilla
region

29. Palatine branches
• The palatine branches include- greater palatine & lesser
palatine branches.
• GP decends down through pterygopalatine
canal,emerging on hard palate through GP
foramen,supplying sensory innervation as far as till
premolar area.
• The lesser palatine nerves emerge from LP foramen n
goes posteriorly supplying the soft palate,tonsillar region.

30. Pharyngeal part
• Pharyngeal part – small branch leaves PPG &
passes through the pharyngeal canal & supply
nasopharynx,posterior to auditory tube.

31. • Infraorbital- Passes through the inferior orbital
fissure to enter the orbit.
• Passes anteriorly through the infraorbital groove and
infraorbital canal and exits onto the face via the
infraorbital foramen as cutaneous branch of V2.
• Branches – palpebral, nasal, superior labial.

32. Terminal branchesin the face :
a)Palpebral: to the lowereyelid.
b)Nasal: to the sideof thenose.
c)SuperiorLabial: to the upperlip.

33. Branches within INFRAORBITAL CANAL
• MSA - variable nerve.
• When present, branches off the infra orbital
nerve,while travelling in the infra orbital canal.
• which supplies the maxillary sinus as well as the
upper premolar, mesiobuccal root of 1st molar & the
gums, and the mucosa alongside the same teeth.

34. • ASA- while in the canal, has a small branch that
supplies the nasal cavity in the region of the inferior
meatus and inferior corresponding portion of the
nasal septum.
• As it descends down, it innervates part of the
maxillary sinus; anterior teeth and the gingiva and
mucosa alongside the same teeth.

35. Mandibular nerve
• The largest division of the
trigeminal nerve.
• It is a mixed nerve has a sensory
root and a motor root.
• It leaves the skull through the
Foramen Ovale
• Below foramen ovale, the 2 roots
unit to form the trunk of the nerve.
• Then , it divides into anterior &
posterior divisions

36. Branches From the Main Trunk
• Meningeal branch- re-enters the cranium through foramen spinosum
with the middle meningeal artery & and supply the dura matter.
• Nerve to the medial pterygoid muscle, which supplies not only the
medial pterygoid, but also the tensor veli palatini muscle &tensor
tympani.
• Nerves to tensor tympani, and tensor veli palatini muscles

37. Branches From the Anterior Division
• Masseteric nerve to the masseter
muscle
• Deep temporal nerves to the
temporalis muscle, anterior &
posterior.
• Nerve to the lateral pterygoid
muscle
• Buccal nerve to the skin and the
mucous membrane of the cheek .It
is the only sensory branch of the
anterior division of the mandibular
nerve.

38. Branches From the Posterior Division
• Auriculo temporal
• Lingual
• Inferior alveolar
• Mylohyoid

39. Auriculotemporal nerve
• Supplies the skin of the auricle, the
external auditory meatus, the
temporomandibular joint, and the
scalp.
• This nerve also conveys
parasympathetic secretomotor fibers
from the otic ganglion to the parotid
salivary gland.
a. Anterior Auricular
b. Branches to
external acoustic meatus
c. Articular
d. Parotid
e. Superficialtemporal

40. Lingual nerve
• which descends in front of the inferior
alveolar nerve and enters the mouth .
• It then runs forward on the side of the
tongue and crosses the submandibular
duct.
• In its course, it is joined by the chorda
tympani nerve, and it supplies the
mucous membrane of the anterior two
thirds of the tongue and the floor of
the mouth.
• It also gives off parasympathetic
secretomotor fibers to the
submandibular ganglion.

41. Inferior alveolar nerve
• Enters the mandibular canal to
supply the teeth of the lower jaw
and emerges through the mental
foramen (mental nerve) to supply
the skin of the chin .
• Before entering the canal, it gives
off the mylohyoid nerve, which
supplies the mylohyoid muscle
and the anterior belly of the
digastric muscle.

42. • Incisivenervewhich continues forwards .It
supplies the canine and incisor teeth of the
lower jaw.

43. • The inferior alveolar nerve within the mandibular
canal, forms the inferior dental plexus, which
innervates the lower teeth.
• A major branch of this plexus, the mental nerve,
supplies the skin and mucous membranes of the lower
lip, skin of the chin, and the gingiva of the lower
teeth.

44. 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 and nasal cavity, max sinus, palate,
nasopharynx.
3. Otic Ganglion:below foramen ovale in infra temporal fossa.
On the medial surface of mandibular nerve. Supplies secretomotor fibres
to the parotid gland.
4.Submandibular Ganglion: related to lingual nerve, rests on hypoglossus .
supplies post ganglionic parasympathetic secretomotor fibres to
submandibular and sublingual gland.

46. Examination of the Trigeminal Nerve
• Testing motor supply
• Test for corneal reflex
• Testing sensory supply
• Testing jaw jerk

47. Clinical Relevance
• Testing sensory supply: ask the patient to close their
eyes and introduce a cotton wisp to areas of the face
supplied by the three divisions of the trigeminal nerve
to detect tactile sensory competence.
• Testing motor supply: ask the patient to clench their
jaw as you palpate superior to the zygomatic arch to
feel for contraction of the temporalis and then repeat
palpating inferiorly for the masseter. Ask the patient to
open their mouth and deviate their mandible to the
right and left to check for competence of the medial
and lateral pterygoid muscles.

48. • Corneal Reflex
• The corneal reflex is the
involuntary blinking of the eyelids –
stimulated by tactile, thermal or painful
stimulation of the cornea.
• In the corneal reflex, the ophthalmic nerve
acts as the afferent limb – detecting the
stimuli.
• The facial nerve is the efferent limb, causing
contraction of the orbicularis oculi muscle.
• If the corneal reflex is absent, it is a sign
of damage to the trigeminal/ophthalmic
nerve, or the facial nerve.

49. Testing jaw jerk
• Place a finger on the chin & is tapped at a
downward angle while the mouth is held
slightly open.
• In response, muscles will jerk the mandible
upwards. Normally this reflex is absent or
very slight.
• In upper motor neuron lesions,
above the level of the pons,
the closure is brisk.

50. Clinical pathology
• TRIGEMINAL NEURALGIA (TIC DOULOUREUX)
• It’s a clinical condition which presents itself as
paroxysmal episodes of acute pain of sudden
onset and brief duration in the area of
distribution of 1 or more branches of the
trigeminal nerve,usually the 2nd & 3rd divisions.
• The anticonvulsive agents, carbamazepine or
oxcarbazepine, constitute the first-line treatment.
Microvascular decompression or ablative
procedures should be considered when
pharmacotherapy is ineffective or intolerable.

52. TCR
• TCR is a triad of bradycardia ,bradypnea and
gastric motility changes due to the efferent
activation of the vagal nerve in response to
the pressure distribution in the trigeminal
nerve.
• This unexpected phenomenon is usually seen
in orbital injuries and during surgical
manipulation of craniofacial structures in the
distribution of trigeminal nerve.

53. • Knowledge of the TCR is essential as it may
mimic a closed cranial injury or a cardiac
dysarrythmia in a post traumatic patient to
avoid unwarranted surgical intervention.
• A detailed ophthalmic examination in
maxillofacial injuries is essential.

55. LESIONS
• Lesion at foramen rotundum
or within infra orbital canal
involves maxillary nerve.
This results in paraesthesia
of the cheek & upper teeth.
• Loss of sneeze reflex as the
nerve supplies the afferent
limb of ‘’sneeze reflex’’.
•Lesion at the foramen ovale
involves mandibular nerve &
paraesthesia along the
mandible, lower teeth,& side
of the face.
•Paralysis of muscles of
mastication .
•Loss of the ‘’ jaw jerk
reflex ‘’, as mandibular nerve
supplies both the afferent &
efferent limbs for the jaw
jerk reflex.

56. Multiple scelrosis
• During periods of multiple sclerosis
(MS) activity, white blood cells are
drawn to regions of the white matter.
• These initiate and participate in the
inflammatory response.
• During the inflammatory phase, the
myelin surrounding the axons is
destroyed in a process known as
demyelination.
• Approximately 2 % of patients with
MS also have symptoms of trigeminal
neuralgia.

57. Herpes zoster of CN V

58. Trigeminal Schwannomas
• Arise from the trigeminal ganglion and cause
numbness and paresthesias are the most
common symptoms from these tumors, but
pain and crawling sensations are sometimes
present.
• Other tumors and perineurial spread of other
cancers in the region of the trigeminal
ganglion are rare, but can cause variable
clinical symptoms.

59. The superior orbital fissure syndrome
• Is a complex of impaired function of the cranial
nerves (III, IV, V, and VI) that enter the orbit
through the superior orbital fissure.
• Three major precipitating factors for SOFS are
trauma, tumor, and inflammation.
• Any unnatural narrowing of SOF due to trauma of
high impact to the upper and midface
(frontobasal skull, Le Fort II, III, and zygomatic
complex fractures) can precipitate this condition.

60. CLASSIFICATION OF NERVE INJURY
• Seddon’s Classification(1943)
• Sunderland’s Classification(1951)

61. Nerve injuries
Neuropraxia
• the mildest injury type that is transient.
• There is no effect on nerve continuity.
• Caused by a temporary disturbance in the conduction pathway that blocks neural
transmission but does not damage the axon.
• Symptoms include numbness, tingling, and loss of vibration and postural sensation.
• All of these effects resemble the common effects of local anesthesia.
• This type of injury will recover completely providing the cause, for example, ongoing
compression, is removed

62. Axonotmesis
– Complete interruption of nerve fibres but the
connective tissue is still intact.
– complete loss of motor, sensory, and autonomic
function.
– Tinel’s sign can be elicited initially at the site of the
injury and will advance distally over time

63. Neurotmesis
– Neurotmesis involves complete severance of the nerve.
– Complete functional loss and recovery without surgical
intervention is unlikely.
– There is a complete loss of motor and sensory function.
– Recovery can only occur after appropriate surgical repair of the
nerve
– on clinical examination and neurophysiology assessment may
be the same for axonotmesis and neurotmesis, yet there is a
clear difference in prognosis and management.

64. Sunderland’s classification

65. TRIGEMINAL NEUROPATHY
• Well recognized disorders characterized and manifesting as skin and mucosal
numbness in the region innervated by the trigeminal nerve.
• Facial numbness indicates trigeminal sensory alteration affecting the trigeminal
system
• They can be the result of traumatism, tumors, or diseases of the connective tissue,
infectious or demyelinating diseases, or may be of idiopathic origin.
• The clinical exploration reveals a loss of sensitivity in the cutaneous territory
corresponding to the affected nerve, which can be partial (hypoesthesia) or
complete (anesthesia).

66. Trigeminal nerve injuries
• CN5 may be injured by
trauma,tumors,aneurysms or meningeal
infections.
• The sensory & motor nuclei in the pons &
medulla may be destroyed by intermedullary
tumors or vascular lesions.
• An isolated lesion of the spinal trigeminal tract
also may occur with multiple sclerosis.

67. INJURY CAUSES THE FOLLOWING-
• Paralysis of muscle of mastication with
deviation of the mandible towards the side of
the lesion.
• Loss of the ability to appreciate soft
tactile,thermal or painful sensations in the
face.
• Loss of corneal reflex & sneezing reflex.

68. • Eg: involvement of the IAN in mandibular
fractures and infra -orbital in maxillary and
ZMC fractures
• Loss or diminished sensation around the lower
lips ,usually involving the lower lip and/or
tongue areas causing a mixture of pain,
numbness that may be present all the time or
intermittently.

69. • Lingual nerve lies in contact with lingual
gingiva medial to 3rd molar, may get injured
during removal of the tooth.

70. Conclusion

71. Bibliography
• Snell’s 8th edition
• Textbook of Local Anesthesia-Stanley F
Malamed
• Gray’s Anatomy
• Articles
• Internet sources

72. Thank you 

73. Applied anatomy
• Supraorbital injuries
Trauma to the supraorbital margin may damage the
supraorbital and/or supratrochlear nerves causing sensory
loss in the scalp.
• Ethmoid tumours
Malignant tumours of the mucous lining of the ethmoid air cells
may expand into the orbits, damaging branches of Va. This
may lead to displacement of the orbital contents causing
proptosis and squint, and sensory loss over the anterior nasal
skin.
• Nasal fractures
Trauma to the nose may damage the external nasal nerve as it
becomes superficial. Sensory loss of the skin down to the tip
of the nose.

74. • Infraorbital injuries: malar fractures
Trauma to infraorbital margin may cause sensory loss of infraorbital
skin.
• Maxillary sinus infections
Infections of the maxillary sinus may cause infraorbital pain or
may cause referred pain to other structures supplied by Vb .
• Maxillary teeth abscesses :The roots of the maxillary teeth
(especially the second molars)are intimately related to the maxillary
sinus. Root abscesses are painful.
• Maxillary antrumtumours
Malignant tumours of the mucous lining of the maxillary antrum may
expand into the orbit, damaging branches of Vb, particularly the
infraorbital. This may lead to anaesthesia over the facial skin. The
orbital contents may also be displaced causing proptosis

75. • TCR is actually endogenous physiological
protective mechanisms found in brain against
ischemia.
• It is one of the oxygen conserving reflexes.
• Within seconds of initiation of such reflex, there
is activation of sympathetic nerves which leads to
cerebro vascular vasodilatation.
• These responses are exaggerated and put the
patient at risk .
• During initial period of vagal stimulation,the
cardiac depression is at peak.

76. Management of nerve injury
1.Manipulation of the nerve (neurolysis)
2.Repair with a direct anastomosis or the use of
graft
3.Coaptation
4.Neurorrhaphy
5. Entubulation