This lecture is about one of the 12 cranial nerves ..
it handles with the gross anatomy and the microanatomy including the nuclei ..
also this lecture includes the branches, innervation, lesions and how to test the integrity of this nerve ...
Trigeminal nerve V
( V )
Abbas A. A. Shawka
Nerve Modality Nucleus location Distribution
nucleus of V nerve
posterior part )
Spinal nucleus of V
Pons – C2 level Pain and
nucleus of V nerve
SVE Motor nucleus of V
Pons ( medial
anterior belly of
veli palatini, and
• The trigeminal nerve exits
from the anterolateral surface
of the pons as a large sensory
root and a small motor root .
• These roots continue forward
out of the posterior cranial
fossa and into the middle
cranial fossa by passing over
the medial tip of the petrous
part of the temporal bone .
• In the middle cranial fossa the
sensory root expands into the
trigeminal ganglion , which
contains cell bodies for the
sensory neurons in the
trigeminal nerve and is
comparable to a spinal
• The ganglion is in a depression
(the trigeminal depression) on
the anterior surface of the
petrous part of the temporal
bone, in a dural cave (the
trigeminal cave ) .
• The motor root is below and
completely separate from the
sensory root at this point.
• Arising from the anterior
border of the trigeminal
ganglion are the three
terminal divisions of the
trigeminal nerve, which in
descending order are:
• the ophthalmic nerve V1
• the maxillary nerve V2
• the mandibular nerve V3
• Note how the trigeminal nerve and its divisions pass
through the lateral wall of cavernous sinus !!
• Other nerves also pass through the lateral wall of cavernous sinus !!?
Ophthalmic nerve V1
• Purely sensory.
• From trigeminal ganglion
courses in lateral wall of
cavernous sinus interior to CN
IV, enters orbit through
superior orbital fissure (SOF)
• Befor leaving cavernous sinus it will give :-
1. Meningeal branch :- to close related structures ( not leave through SOF )
2. Frontal nerve :- enters orbit above the common tendinous ring then divides into
supra-orbital and supratrochlear nerves
3. Lacrimal branch :- enters orbit above the CTR and receive parasympathetic fibers
from the great petrosal nerve of CN VII through the zygomatic branch of CN V2
4. Nasociliary nerve :- enters the orbit through the CTR then divided to ( 6 )
• Nasociliary nerve branches = ( 6 branches ) !!
1. Infratrochlear nerve
2. Anterior and posterior ethmoidal nerves
3. Internal nasal nerve
4. External nasal nerve
5. Long ciliary nerve ( sensory + sympathetic to DPM )
6. Short ciliary nerve ( sensory + parasympathetic from CN III through ciliary
ganglion to sphincter papillae and )
Maxillary nerve V2
• Purely sensory
• MMN is given directly after
exit from the trigeminal
ganglion and accompanies the
• Corse in inferiolateral way in
CS inferior to V1
• Exit cranial cavity through
foramina rotundum to enter
the pterygopalatine fossa
1. Infraorbital nerve :- enter orbit through IOF and gives :-
- Posterior superior alveolar nerve - Middle superior alveolar nerve
- Anterior superior alveolar nerve - Inferior palpebral branch
- External nasal branch - Labial branch
2. Zygomatic nerve :- ( IOF ) then divided into :-
- Zygomaticotemporal n.
- Zygomaticofascial n.
- Parasympathetic fibers from CN VII – GPN – Pterygo. Ganglia – Zygomatic nerve (
V2 ) – lacrimal nerve ( V1 )
3. Branches bass through the pterygopalatine ganglion without synapsing in it
- Orbital ( to periosteum )
- Greater and lesser palatine nerves
- Posterior superior nasal
- Nasopalatine nerve
Mandibular nerve V3
• Sensory and motor
• The largest
• The sensory root is inferior to
V1 and V2 in the trigeminl
depression then it exit through
• V3 do not enter the cavernous
• Mandibular nerve lies in the
• Branch of V3
• Carry 2 type of fibers :
• 1- sensory fibers
• Give sensation to parotid gland,
auricle , hairy temporal and TM joint.
• 2- parasympathetic ( secretomotor )
to parotid gland ( from otic ganglion –
lesser petrosal nerve – tympanic
nerve – IX – inferior salivatory nucleus
• Pain from parotid fascia if felt by
GRAET AURICULAR NERVE !!!
Branches of auriculotemporal nerve
• Anterior auricular
• Branches to external acoustic meatus ( EAM )
• Articular branch
• Superficial temporal branches
• Communicating branches with CN VII
• Branch from the posterior trunk ( which is mainly sensory ) of V3.
• Carry three types of fibers
1. Sensation ( from V ) to tongue.
2. Test fibers to anterior 2/3 of the the tongue ( Chorda tympani – VII – solitary
nucleus tract )
3. Secretomotor ( parasympathetic fibers ) ( chorda tympani – VII – superior
salivatory nucleus )
Inferior alveolar n.
• Branch of mandibular nerve ( V3 )
• Only 1 type of fibers after giving nerve to
• ( afferent fibers ) sensation !!
• 3 branches ( nerve to myelohyoid , mental
& incisive )
Motor component of V n.
• Beneath the trigeminal sensory
• Exits the cranial cavity through
foramina ovale the joins the sensory
root of CN V3 to form the
mandibular nerve !
• Trigeminal nerve is motor for (8)
• Affections of the motor part of the fifth
nerve, whose fibres run in the mandibular
branch, are very unusual. Test for contraction
• The commonest condition affecting the
sensory part of the nerve is trigeminal
neuralgia (tic doloureux), of unknown cause
and characterized by pain in the distribution
of the maxillary and/or mandibular
• The ophthalmic branch is rarely involved
and, equally strangely, nor is the complete
distribution of the affected main branch.
• With the maxillary nerve affected the pain is
usually felt deeply in the face and nose
between the mouth and orbit, and with the
mandibular nerve from the mouth up to the
ear and the temporal region—but not along
the lower part of the mandible or the angle,
where the nerve supply is by the great
• Injection or electrocoagulation of the
trigeminal ganglion may be necessary to
abolish the pain.
• It should be noted that the sensory
distribution of the mandibular nerve
extends into the external ear and on to
the temporal region via the
auriculotemporal branch, and that the
ophthalmic nerve distribution stretches
from the tip of the nose to the vertex of
the skull, well beyond the hairline and as
far back as a line drawn upwards from
• The appearance of herpetic vesicles on
the tip of the nose should be a warning
that the cornea may become involved.
• This occurs because the nasociliary
branch of the trigeminal nerve
innervates both the cornea and the
lateral dorsum of the nose as well as the
tip of the nose
• The afferent side of the corneal reflex
depends on the ciliary branches of the
nasociliary part of the ophthalmic nerve.
Disappearance of the reflex is often the
first sign of a lesion of the ophthalmic
nerve; test by gently touching the cornea
(not the conjuctiva) with cotton wool.
• Initially test the sensory branches
by lightly touching the face with a
piece of cotton wool followed by a
blunt pin in three places on each
side of the face:
1. around the jawline,
2. on the cheek and,
3. on the forehead.
• The corneal reflex should also be
examined as the sensory supply to
the cornea is from this nerve. Do
this by lightly touching the cornea
with the cotton wool. This should
cause the patient to shut their