The trigeminal nerve is derived from the first pharyngeal arch during embryo development. It provides sensory innervation to the face and motor innervation to the muscles of mastication. The trigeminal nerve has four nuclei and its branches include the ophthalmic, maxillary, and mandibular nerves. Trigeminal neuralgia is a condition characterized by sudden, severe facial pain and is commonly caused by compression of the trigeminal nerve root from vascular structures.

3. EMBRYOLOGY OF THE NERVE
During the development of embryo, the pharyngeal arches
appear in the fourth and fifth week.
It give rise to six pharyngeal arches, of which the 5th arch
dissapears.

4. Each arch is characterized by its own:
muscular component
nerve component
arterial component
skeletal component
- Trigeminal nerve is derived from 1st pharyngeal arch

5. Musculature of the first pharyngeal arch includes:-
Muscles of mastication :
Temporalis
Masseter
Pterygoids
Anterior belly of diagtric
Mylohyoid
Tensor tympani
Tensor palatini
The nerve supply to these muscles is provided by
mandibular division of trigeminal nerve.

6. Mesenchyme from the 1st arch also contributes to
the dermis of the face,hence sensory supply to the
skin of the face is provided by ophthalmic, maxillary
and mandibular branches of the trigeminal nerve.

7. Nuclei of trigeminal nerve:-
It has got 4 nuclei :
1) Main sensory nuclei
2) Spinal nuclei sensory
3) Mesencephalic nuclei
4) Motor nuclei

8. The trigeminal nerve nucleus

11. course

12. Examination
• Jaw reflex
• Corneal reflex
• Sensory
• Motor

13. Corneal Reflex

14. APPLIEDANATOMY:-
1.Trigeminal neuralgia.
2. Herpes zoster ophthalmicus.
3.Wallenberg Syndrome.
4. Nerve blocks of maxillary and mandibular region.

15. Trigeminal Neuralgia:-
also known as Fothergill’s disease
Tic douloureux (painful jerking)
it is defined as ,
sudden ,usually ,unilateral ,severe ,brief ,stabbing ,
lancinating , recurring pain in the distribution of
one or more branches of trigeminal nerve.
Mean age: 50 y onwards
Female predominance (male : female = 1:2 ~2:3)

16. Pathogenesis of trigeminal neuralgia
It is usualy idiopathic.
The probable etiologic factors are:-
Intra cranial tumors:-Traumatic compression of the
trigeminal nerve by neoplastic (cerebellopontine
angle tumor) or vascular anomalies eg arteriovenous
malformations
Infections :- granulomatous and non granulomatous
infections involving 5th cranial nerve.

17. postherpetic neuralgia
Demyelinating conditions
Multiple sclerosis (MS)
Petrous ridge compression
Intracranial vascular abnormalites

18. Pulsation of vessels upon the trigeminal nerve root do not
visibly damage the nerve. However, irritation from repeated
pulsations may lead to changes of nerve function, and delivery
of abnormal signals to the trigeminal nerve nucleus. Over time,
this is thought to cause hyperactivity of the trigeminal nerve
nucleus, resulting in the generation of TN pain.

19. Clinical characteristics:-
sudden
unilateral
intermittent paroxysmal
sharp shooting
lancinating shock like pain elicted by slight touching

20. superficial trigger points which radiates across the
distribution of one or more branches of the trigeminal
nerve
pain rarely crosses the midline
pain is of short duration and last for few seconds to
minutes
in extreme cases patient has a motionless face called
the frozen or mask like face
presence of intraoral or extraoral trigger points

21. TRIGGER ZONE

22. Provocated by obvious stimuli like
Touching face at particular site
Chewing
Speaking
Brushing
Shaving
Washing the face
The characteristic of the disorder being that the
attacks do not occur during sleep.

23. DIAGNOSIS:-
CLINICAL EXAMINATION with HISTORY is mandatory
Response to treatment with tablet of carbamazepine
is univeral
Injections of local anaesthetic agents into patients
trigger zone gives temporarily relief from pain.

24. TREATMENT:-
Medical treatment
Surgical treatment:-
Peripheral injections
Peripheral neurectomy
Cryotherapy
Peripheral radiofrequency
Neurolysis(thermocoagulation)
Gasserian ganglion procedures

25. E HERPES ZOSTER OPHTHALMICUS:-
Caused by Varicella zoster
Predilection for nasociliary branch of ophthalmic
division of the trigeminal nerve
CLINICALFEATURES:-
Cutaneous lesions:-
Rash
Vesicle
Pustule crust permanent scar

26. Ocular lesions:-
Eyelid:- Perorbital pain
Oedema
Hyperasthesia
Conjunctivitis
Scleritis
Corneal scarring
Glaucoma

27. TREATMENT:-
Acyclovir 800mg 5 times /day within 4 days of onset
of rash
Analgesics
Antibiotic ointments
Systemic steroids 60mg/day
Corneal grafting

28. Wallenberg syndrome:-
a stroke which causes loss of pain/temperature
sensation from one side of the face and the other side
of the body.
ETIOLOGY:-
In the medulla, the Ascending Spinothalamic Tract
(which
carries pain/temperature information from
the opposite side of the body) is adjacent to the
Descending
Spinal Tract of the fifth nerve (whch carries pain
/temperature information from the same side of the

29. A stroke cuts off the blood supply to this area
Destroys both tracts simultaneously.
Results in loss of pain/temperature sensation in a
unique “checkerboard” pattern (ipsilateral face,
contralateral body)
Characteristic diagnostic feature.