Opthalmic division of trigeminal nerve/ oral surgery courses

INDIAN DENTAL ACADEMY
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 The trigeminal nerve is the fifth cranial nerve and is
the largest of all. It is so called because it consists of
three divisions namely opthalmic, maxillary and
mandibular
 Type – it is a mixed nerve and so it is both motor and
sensory nerve.
 Two roots, motor and sensory emerge from the ventral
aspect of pons.

 Sensory root larger and motor root smaller. The motor
root lies ventrimedial to sensory root. The sensory
root passes forward from the posterior cranial fosse
and joins the concave posterior margin of trigeminal
ganglion.
 The motor root passes forward and the passes below
the sensory root and trigeminal ganglion in the
trigeminal cave and finally join with sensory part of
mandibular nerve in the foramen ovale and form trunk
of mandibular nerve.

 The trigeminal ganglion is a semilunar ganglion which
lies in the trigeminal fossa on the anterior surface of
the petrous temporal base near its apex. The ganglion
is crescent shaped. It has convex border facing
anterolaterally and on concave border facing
posteromedially. The ganglion is enclosed with a
pouch like recess of duramater. This recess is called
trigeminal cave. It bulges into the posterior lateral part
of cavernous sinus.

 Trigeminal nerve has three sensory nuclei; They are
arranged in three groups namely chief or principal
sensory nucleus, spinal nucleus and mescencephalic
nuclei .
 Deep origin or Nucleus of Origin
 Sensory Nucleus (Principal) - Situated within the
pons lateral to the Motor Nucleus of the nerve. It
receives sensory fibres for touch sensation.

 Spinal Nucleus of Trigeminal nerve – An elongated nucleus
extending from the sensory nucleus, cranially to second or
third cervical spinal segments caudally. It receives pain and
temperature from trigeminal area. This nucleus- us receives
general somatic sensations from facial, glossopharyngeal
and vagus nerves.
 Mesencephalic Nucleus - Situated in the central grey
matter of mid brain on either side of cerebral aqueduct. It
receives proprioceptive sensations of the fifth nerve.

 Motor Nucleus - Situated within the pons, medial
to sensory nucleus and the fibres from it form the
motor root of the nerve. This nucleus represents
the special visceral efferent column.
 Superficial origin - Two roots : Motor and
 sensory emerge from the ventral aspect of the
Pons.
 The molor nucleus is situated with like pons,
medial to sensory nucleus and fibers from it form
the motor root of the nerve.

1) It is one of division of trigeminal nerve.
2) It is purely a sensory nerve.
3) Arises from convex anterior margin of trigeminal
ganglion.
4) After origin it was on the lateral wall of cervernous
sinus below 4th cranial nerve and above maxillary
division.

5) In the anterior part of cavernous sinus, it terminates by
dividing into
 Frontal
 Lacrimal
 Nasociliary

1) Largest branch of opthalmic nerve.
2) It is a sensory nerve
3) It is enters the orbit through lateral part of superior
orbital fissure outside the annulus tendinous
communis (ring) lateral to trochlear nerve.
4) In the orbit the nerve passes forward between the
roof of orbit and levator palpebrae superiors.
5) It terminates in the midway between base and apex
of the orbit by dividing into
a) Supratrochlear
b) Supraorbital branches

A.Supraorbital nerve – It passes through the
supraorbital notch or foramen and terminates by
distributing following branches.
 Branches to upper eyelid an conjunctiva.
 Deep to frontals is divides into medial and lateral
branches which pierce the muscle and supply skin of
scalp, forehead upto lambdoid suture, mucous
membrane of frontal sinus and pericardium.

B. Supratrochlear
1. It passes forward above the trochlea of superior
oblique muscle of eyeball and them emerges from
orbit medial to supra-orbital foramen and
accompanied by supratrochlear vessels.
2. It gives a) Communicating branch it infratrochlear
branch of nasociliary nerve b) Branches to
conjunctiva, skin of upper eyelid and lower part of
forehead.

1) Smallest of the branches of opthalmic nerve and sensory
nerve.
2) Receives few filaments from trochlear nerve and these
filaments are those which pass from opthalmic to
trochlear nerve previously.
3) It passes to orbital through lateral compartment of
superior orbital fissure outside annulus tendinous bing
and lateral to frontal nerve.

4) In the orbit it passes above lateral rectus accompanied by
lacrimal artery and receives a twig form zygomatico fibers
temporal branch which carries post ganglionic
seeretomotor fibers for lacrimal gland.
5) It gives branches to lacrimal gland and conjunctiva.
6) Finally it pierces orbital septum and ends in the skin of
upper eyelid and joining with branches of facial nerve.

1) It is a sensory nerve and one of the three branches of
ophthalmic nerve
2) Origin it arises from the ophthalmic nerve in the anterior
part of cavernous sinus.
3) It enters the orbit by passing through the middle
compartment of superior orbital fissure within the
annulus tendinous communis and them through the two
heads of lateral rectus muscle.

4) Within the superior orbital fissure, it lies between two
rami (divisions) of occulomotor nerve and abducent
nerve .
5) Within orbit – it at first lies lateral to a Optic nerve and
then crosses above it from lateral to medial side and
passes below superior rectus and superior oblique muscle
and finally passes towards the medial wall of orbit.
6) Ultimately it passes through anterior elthmoidal
foramen and terminates by continuing as anterior
ethmoidal nerve.

7) Branches
A. Branches of communication – Sympathetic plexus,
3rd nerve, culinary ganglion. Before crossing optic
nerve, a branch arises and joins ciliary ganglion
forming its sensory root and sometimes also
sympathetic root.

B. Branches of distribution
a) Long ciliary branches – two or three in number and
arise during crossing of optic nerve and distribute it
ciliary body, iris, cornea and usually contains post
ganglionic sympathetic fibers for dilator pupillae.
b) Posterior ethmoidal – Passes through the posterior
ethmoidal foramen and distributes to ethmoidal and
sphenoidal air sinuses.

c) Infratrochleor - it communicates with 4th nerve near
the pulley of superior oblique muscle and escapes out
of orbit and supplies skin of eyelids, upper part of
nose, conjunctiva, laerimal sac and caruncle.
d) Anterior elthmoidal- it is the continuation of
nasocilitary nerve and passes through anterior
ethmoidal foramen and canal and enters the cranial
cavity and then passes in the groove on the upper
surface of cribriform plate and passes through a slit at
the side of crista galli and enters the nasal cavity. Here
it divides into. www.indiandentalacademy.com

 Internal nasal branch supplying the mucous
membrane of front part of nasal septum and anterior
part of lateral wall of nasal cavity .
 External nasal branch supplying ala, apex and
vestibule of nose.

 Testing of opthalmic division of trigeminal nerve
 The integrity of the division is tested by checking the
corneal reflex – touching the cornea with a wisp of cotton
which evokes a reflexive blink if the nerve is functional.
 Injury to the supraorbital and supratrocchear branches of
the ophthalmic nerve can occur with facial or head trauma,
dental trauma or surgery or any surgical procedure on face.

 The sensory loss is temporarily related to the injury.
Nerve regeneration can occur and is accompanied by
facial pain.
 The supraorbital branch can be damaged by blunt
injury or a result of the fracture of the upper margin of
the orbit.

 Common lesions involving opthalmic nerve are.
a) Herpes zoster opthalmicus is caused by herpes zoster
virus.
It may produce lesion in the cranial ganglia with 20%
cases involving the trigeminal ganglion.
The lesion in characterized by eruption of group of
vesicles following the course of affected nerve.
Usually the cornea is involved, often resulting in
painful corneal ulceration and subsequent scanning of
cornea.

 Herpes zoster (Commonly referred to as singles) and post
herpetic neuralgia result from reactivation of the varicella
zoster virus acquired during primary varicelle infection or
chicker pox. Where as varicella is generally a disease of
childhood, lerpes zoster and post herpetic neuralgic
become more common with increasing age.

 Occular complications occur in approximately one half
of patients with involvement of ophthalmic division of
trigeminal nerve. There complications include
mucopurulent conjunctivitis, episcleritis, keratitis and
anterior uveitis. Cranial nerve palsies of third, fourth
and sixth cranial nerve may occur affecting
extraorccular motility.

 Viral conjunctivitis may sometime involve the opthalmic
division of trigeminal nerve characterized by prodrome
fever, malaise, nausea, vomiting and severe pain and skin
lesions along the course of opthalmic division of trigeminal
nerve.
 Miller Fisher syndrome affect the opthalmic division by
trigeminal nerve and is associated with opthalmophlegia,
alaxia and blink reflex.

 Blink reflex is elicited electrophysiologically by mean
of electrical stimulation of supraorbital nerve and is
helpful in detecting the peripheral lesion of opthalmic
division of trigeminal nerve.
 Horner syndrome is associated with lesions of
nasocillary nerve, a branch of opthalmic division of
trigeminal nerve. It is characterized by miosis, partial
ptosis, exopthalmus, anhidrosis, absence of cirlio-
spinal reflex.

 Although much of this division’s course is through the
orbit, nose and cranium still it may be afflicted with a
lesion of structural disorder with may cause oro-facial
pain. Ignorance of this pain may lead to diagnostic and
therapeutic failure.

 Since the supraorbitla nerve supplies the mucous
membrane of the frontal air sinus and sends some
branches to deeper tissue of scalp, in frontal sinusitis
pain is referred to the area of scalp supplied by the
supraorbital nerve and is more commonly known as
frontal headache.

 Leprosy caused by M. Leprae may affect the nasocillary
branch of the ophthalmic division. The cornea is richly
supplied by nerves of nasocillary branch of opthalmic
division of trgeminal nerve and has no blood supply.
So the M. Leprae can invade the structure only by
direct extension and form micronodular swelling
which can be detected early as they appear in the
upper outer quadrant as faint discrete and later as
dense white grains. This early detection is possible due
to transparency of cornea.

 In other parts of cornea these form diffuse superficial
punctuate characteristic of keratitis and are lepromatous
granuloma.
 Ultimately lepromatous granuloma may from interstitial
keratitis which may seriously affect vision.
 Headache along the course of opthalmic nerve may be due
to lesion above tentorium. Lesion below tentorium cause
headache along the distribution of upper three cervical
nerves or ninth and tenth cranial nerve.

 Neuroopthalmic complication of AIDS involve the
opthalmic division of left trigeminal nerve
accompanied by several small dendritic corneal lesions
of eye.

 Clinically oriented Anatomy (51th Edition) – By Keith
L Moore, Arthur F. Dalley
 Textbook of Anatomy – By Samarendra Mitra
 Text Book of Anatomy – By Inderbir Singh
 Human Anatomy of Dental student by Mahindra
Kumar Anand

Opthalmic division of trigeminal nerve/ oral surgery courses

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