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1. Anatomical branches of the cranial
nerves and their localization
Prepared by: Supervised by:
Maryam Saad Dr. Ronak Saber
Dleen Hemn
Zheen Handren

2. Introduction
Those are 12 cranial nerves that
are located at the back of your
brain. They help us to feel, touch,
hear, see, smell, and also taste.
They send electrical signals
between different parts in our
upper body, for example between
the brain, neck, face, and torso.
Those 12 cranial nerves are

3. The 12 cranial nerves are
● Olfactory I: nerve used for sense of smell
● Optic II: nerve used for sight
● Oculomotor III: nerve used for the ability to move and blink your
eyes
● Trochlear IV: nerve used to move your eyes up and down or back
and forth
● Trigeminal V: nerve that gives us the ability to have sensations in
our face, cheeks, taste and jaw movements.
● Abducens VI: nerve that give ability to move our eyes

4. The 12 cranial nerves
● Facial VII: nerve used for facial expressions and sense of taste
● Vestibulocochlear VIII: nerve used for sense of hearing and
balance
● Glossopharyngeal IX: nerve that allows the ability to taste and
swallow
● Vagus X : nerve for digestion and heartbeat
● Accessory XI: nerve for shoulder and neck muscle movement
● Hypoglossal XII: nerve that provide the ability to move your
tongue

5. Anatomical branches of the olfactory
nerve and their localization:
The first cranial nerve is the olfactory nerve
(CN I). It is a sensory nerve that manages
smell sensing.The olfactory nerve originate
from the cerebrum and terminate at the
olfactory bulb which is found above the
ethmoid bone but below the frontal lobe and
the olfactory bulb is a relay center for the
transmission of impulses from the olfactory
nerve to the olfactory tract and then to the
olfactory cortex and the olfactory nerve
divides into two branches:
1. Lateral olfactory nerves
which are located in the superior
nasal concha
2. Medial olfactory nerves
which are located along the nasal
septum

6. Anatomical branches of olfactory nerve

7. Anatomical branches of optic nerves
and their localization:
The optic nerve is the second nerve from the
12 cranial nerves and it manages seeing and
sight.
The optic nerve originates from the posterior
part of the eyeball to the suprasellar space in
the middle cranial fossa.
And this nerve is about 35 mm to 55 mm in
length and is divided into four parts :
1. optic nerve head that is the intraocular
part which is 1 mm in length which is the most
anterior part of the optic nerve .
2. Intraorbital part which is 25 mm in length
and it originates from the posterior part of the eyeball
to the intraorbital opening of the optic canal.
3. Intracanalicular part which ranges from
4-10 mm in length which is found within the optic
canal and is enclosed by the meninges ( dura,
arachnoid and pia mater)
4. Intracranial part which is 10 mm in length
which extends from internal orifice and then passes
above the suprasellar part of the cavernous sinus.

8. Anatomical branches
of optic nerves:

9. Anatomical branches of oculomotor
nerve and it’s localization:
This nerve is the third cranial
nerve; it has a somatic motor and
visceral motor. It originates from
the oculomotor nucleus and
Edinger Westphal nucleus within
the midbrain of the stem and ends
at the orbit of the eye. This nerve
divides into two branches superior
and inferior:
1. Superior branch of
oculomotor nerve: supplies the
superior rectus and levator
palpebrae superioris with nerves
2. Inferior branch of
oculomotor nerve: innervates the
medial rectus, inferior rectus, and
inferior oblique.

10. Anatomical branches of oculomotor nerve

11. Anatomical branches of Trochlear
nerves and it’s localization :
It is the fourth cranial nerve and it has the longest intracranial course. It has a
general somatic motor nerve which innervates a single muscle which is the superior
oblique muscle.
Originates from the Trochlear nucleus within the gray substance of midbrain.
As in for branches for this cranial nerve there are none that are known but it does
receive connections from the corticonuclear tracts (bilaterally), medial longitudinal
fasciculus (nerve pathway carrying information about the eye movements), and the
tectobulbar tracts (nerve pathway coordinating head and eye movements).

12. Trochlear
nerve

13. 5. Trigeminal nerve
The nervous system's trigeminal nerve is in charge of
carrying pain, touch, and temperature signals from your
face to your brain. Your head has a sizable, triangular
nerve that transmits feeling. One section called the
mandibular nerve involves motor function to help you
chew and swallow.
Trigeminal neuralgia is a terminology for the stabbing
facial sensations that can occur when an impediment,
such as an artery or cyst, irritates or presses on a nerve.
Numbness, or trigeminal neuropathy, can result from
dental operations and other injuries.

14. What is the purpose of the
trigeminal nerve?
The trigeminal nerve
primarily helps you feel
(sensory), although the
mandibular nerve branch
has both sensory and
motor functions. The
trigeminal nerve helps
with:
• Biting, chewing and
swallowing.
• Facial and scalp
sensations

15. Where is the trigeminal nerve?
The trigeminal nerve, also
called the cranial nerve V
(that's the Roman numeral
five), is the fifth of 12
cranial nerves.
There are two trigeminal
nerves in your body, one on
each side. They originate in
your brain and move
throughout your head.

16. What is the anatomy of the
trigeminal nerve?
• The trigeminal nerves begin within four nuclei — or
collections of nerve cell bodies — in your brain. Three of
these nuclei control the functioning of your senses. The
fourth controls motor function (or your movement).
• These three sensory nuclei merge to become one sensory
root near the pons, which is the largest, central part of
your brainstem.
• This sensory root becomes the trigeminal ganglion as it
leaves the brainstem on each side. (A ganglion is a
collection of nerves outside the nervous system.) Each
trigeminal ganglion is located near your temple at the side
of your head, in front of your ear.
• The trigeminal ganglion splits into three trigeminal nerve
branches. These branches travel along each side of your
head to different parts of your face

17. Branches of trigeminal nerve
Ophthalmic: Your scalp and upper face
deliver nerve signals to your brain through this
branch. Eyes are considered to be ophthalmic.
Your eyes, upper eyelids, and forehead are all
affected by the ophthalmic nerve.
Maxillary: This nerve branch is responsible for
sensations in the middle part of your face.
The term "maxillary" signifies the top jaw. The
upper lip, gums, lower eyelids, cheeks, nose,
and maxillary nerves are all connected.
Mandibular: The mandibular (lower jaw)
branch helps with sensation in your lower
face, including your jaws, lower lip, and
mouth. These nerves are also used for motor
activity. They aid in biting, chewing, and
swallowing..

18. 6.Abducens nerve
Cranial nerve six (CN
VI), also known as the
abducens nerve, is one of
the nerves responsible for
the extraocular motor
functions of the eye, along
with the oculomotor nerve
(CN III) and the trochlear
nerve (CN IV).

19. Anatomical course
The abducens nucleus in the pons of the brainstem
gives rise to the abducens nerve. At the medulla-pons
junction, it leaves the brainstem.
After that, it moves into the subarachnoid space and
pierces the dura mater to pass through Dorello's canal.
The abducens nerve exits Dorello's canal and enters
the cavernous sinus at the tip of the petrous temporal
bone (a dural venous sinus). The superior orbital
fissure is where it reaches the bony orbit after passing
through the cavernous sinus.
The abducens nerve exits the bone orbit via
innervating the lateral rectus muscle.

20. Structure and location
The brainstem, which is located low in the back of your brain and
connected to your spinal column, is where the abducens nerve
emerges. The abducens nucleus is the particular region from where
the nerve emerges.
It exits the brainstem and travels into the subarachnoid space, a
region of the cerebral cortex. From there, it rises and pierces the
dura mater, a thick membrane that surrounds the brain and spinal
cord. It then travels via the Dorello canal, which connects the dura
to the skull, before making a steep curve and entering the
cavernous sinus on your face. There, it follows the internal carotid
artery to where it can enter the orbit (the eye socket) through the
superior orbital fissure.
Finally, it connects to the lateral rectus muscle of the eye. The
lateral rectus muscle connects to the outside of your eye, right in
line with the pupil. A small branch of the abducens nerve connects
to the contralateral medial rectus muscle.

21. 7. Facial nerve
The muscles that let you
frown, grin, wrinkle your
nose, raise your eyebrows,
and crease your forehead are
all controlled by the facial
nerve. Both motor and
sensory activities are carried
out by the seventh cranial
nerve. The facial nerve acts
as a link from the brain to a
few facial muscles.

22. What is the purpose of facial nerve?
The facial nerve performs these
motor (movement) and sensory
functions:
• Controls the muscles that make
your facial expressions.
• Controls muscle in your inner
ear that moderates loudness of
sound.
• Helps make tears.
• Sends information about tastes
from your tongue to your brain.

23. Where is the facial nerve ?
The facial nerve is the seventh of 12 cranial nerves in
your nervous system. You have two facial nerves, one on
each side of your head.
The facial nerve:
• Starts in your brainstem.
• Travels through the base of your skull near the
vestibulocochlear nerve, the eighth cranial nerve, which
helps you hear and maintain balance.
• Enters your face through an opening in a bone near the
base of your ear.
• Branches out through an opening near your parotid
gland, a major salivary gland.

24. What are the facial nerve branches ?
The facial nerve has five branches that perform distinct
motor functions:
• Frontal (temporal): Controls your forehead muscles.
• Zygomatic: Helps you close your eyes.
• Buccal: Allows you to move your nose, blink and raise
your upper lip and corners of your mouth to make a
smile.
• Marginal mandibular: Draws your lower lip down (like a
frown) and travels through your middle ear to help you
respond to loud noises.
• Cervical: Controls movement in your chin and lower
corners of your mouth.

25. 8. Vestibulochlear nerve
The internal auditory
meatus contains the
vestibulocochlear nerve
(internal auditory canal).
Balance and hearing are
controlled by the nerve.
Acoustic neuroma,
labyrinthitis, and vestibular
neuritis are all disorders of
the vestibulocochlear
nerve..

26. Anatomy of the nerve
The vestibulocochlear is made up of two nerves—
the cochlear nerve, which is responsible for hearing,
and the vestibular nerve, which is responsible for
balance. As one of the 12 cranial nerves, it runs
between the pons (the middle of the brainstem)
and the medulla oblongata (the lower part of the
brainstem).
The vestibular ganglion is a collection of nerve cells
that emerges from the inner ear carrying the
vestibular portion of the nerve. The spiral ganglion
is where the cochlear portion of the nerve leaves
the cochlea in the inner ear.

27. Equilibrium (Balance)
The vestibular apparatus senses changes in the position of the
head in relation to gravity. The vestibular hair cells are located
in the otolith organs (the utricule and saccule), where they
detect linear movements of the head, as well as in the
three semicircular canals, where they detect rotational
movements of the head. The cell bodies of the vestibular nerve
are located in the vestibular ganglion which is housed in the
outer part of the internal acoustic meatus.
Balance and the vestibulo-ocular reflex are coordinated using
information regarding head position. When the head turns, the
vestibulo-ocular reflex, also known as the oculocephalic reflex,
moves the eyes in the opposite direction to stabilize the
images on the retina. You can practice it by keeping one finger
motionless in front of you at a suitable distance, then moving
your head side to side while keeping your attention on the
finger.

28. Glossopharyngeal nerve IX
The glossopharyngeal nerve originates in
the medulla oblongata of the brain. It emerges
from the anterior aspect of the medulla,
moving laterally in the posterior cranial
fossa. The nerve leaves the cranium via
the jugular foramen. At this point,
the tympanic nerve arises.
At the inferior margin of
the stylopharyngeus, several branches
arise to provide motor innervation to the
muscle. It also gives rise to the carotid
sinus nerve, which provides sensation to
the carotid sinus and body.

29. The branches of glossopharyngeal
• Tympanic nerve (AKA nerve of Jacobson) – carries
parasympathetic fibers and eventually becomes the lesser
petrosal nerve, exiting the skull via the foramen ovale and
synapses in the otic ganglion
• Stylopharyngeal nerve – provides motor innervation to
the stylopharyngeus muscle
• The nerve to carotid sinus – communicates with the
vagus nerve to carry signals from the baroreceptors in the
carotid sinus and chemoreceptors in the carotid body -
this helps in regulating blood pressure (carotid sinus) and
monitoring blood oxygen and CO2 levels (carotid body)
• Pharyngeal branches – join with the pharyngeal branches
of the vagus nerve and sympathetic nerves to form the
pharyngeal plexus, which innervates the muscles of the
pharynx
• Tonsillar branches – provides sensory innervation to the
palatine tonsil
• Lingual branches – supply the vallate papillae, mucous
membrane, and follicular glands of the posterior tongue.

30. Vagus nerve X
It is a functionally diverse nerve, offering many
different modalities of innervation. It is associated with
the derivatives of the fourth and sixth pharyngeal
arches.

31. The vagus nerve has the longest course of all the cranial
nerves, extending from the head to the abdomen.
In the Head In the Neck In the Thorax In the Abdomen
The vagus nerve
originates from the
medulla of the
brainstem. It exits the
cranium via the jugular
foramen, with the
glossopharyngeal and
accessory nerves
In the neck, the
vagus nerve passes
into the carotid
sheath, travelling
inferiorly with the
internal jugular vein
and common carotid
artery.
In the thorax, the
right vagus nerve
forms the posterior
vagal trunk, and the
left forms
the anterior vagal
trunk.
In the abdomen, the
vagal trunks
terminate by dividing
into branches that
supply the
oesophagus,
stomach and the
small and large
bowel.
Within the cranium,
the auricular
branch arises.
This supplies sensation to
the posterior part of the
external auditory canal
and external ear.
Several branches
arise in the neck:
• Pharyngeal
branches
• Superior
laryngeal nerve
• Recurrent
laryngeal nerve
Two other branches
arise in the thorax:
• Left recurrent
laryngeal nerve
• Cardiac branches

33. Accessory nerve XI
The accessory nerve is divided into spinal and
cranial parts.
Spinal Component: The spinal portion arises from neurones
of the upper spinal cord, specifically C1-C5/C6 spinal nerve
roots
Cranial Component: The cranial portion is much smaller
and arises from the lateral aspect of the medulla
oblongata. It leaves the cranium via the jugular foramen,
where it briefly contacts the spinal part of the accessory
nerve.

34. Hypoglossal Nerve XII
• It is mainly an efferent nerve for the tongue musculature. The
nerve originates from the medulla and travels caudally and
dorsally to the tongue.
• The hypoglossal nerve consists of four branches: the meningeal,
descending, thyrothyroid, and muscular. However, only the
muscular branch is considered part of the real hypoglossal
nerve originating from the hypoglossal nucleus. Other branches
originate from spinal nerves (mainly C1/C2) or the cervical
ganglia.

35. Any questions/suggestions?
Thank you!