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The Cranial Nerves
1- Olfactory Nerve
Component:  Sensory Nerve

Course/Pathway:

It arise from the olfactory sensory receptor which is located at the mucous
membrane of nose above superior conchae
...

Then enter olfactory bulb and then enter to synapses in the nasal cortex area in
temporal lobe of cerebral cortex
...
It may be caused by tumor, Stroke,
Fracture of skull
...

It converges on optic disc & exit from the eye
...

The unit with the opposite side of optic nerve to form optic chiasma at the floor
of third ventricle and continue as optic tract
...

Some fibers synapse at superior colliculus of midbrain
...


Functions:

The optic nerve is also responsible for the light reflex and the accommodation reflex
...


Clinical Problems:           
Night Blindness
Color Blindness
Eyesight Problems

Causes:

Optic Neuritis
Tumor

3- Oculomotor Nerve

Component:   Motor Nerve

Origin:

Main Motor Nucleus:
It is situated in the Anterior part of Grey Matter that surrounds the cerebral
aqueduct of the Midbrain
...

It recieves corticonuclearfibers from both cerebral hemispheres
...
 
Through this routes, recieves information from visual cortex
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These fibers synapse in the ciliary ganglion and supply Ciliary Muscles
...

It passes forward between the Posterior Cerebral and the superior cerebellar
artieries
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Superior Ramus:

It supply the extra-occular muscles
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Functions:

              It allows movement of the eye muscles, constriction of the pupil, focusing the eyes and the
position of the upper eyelid
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When object is displaced near to far then Pupil Dilate
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Incomplete lesions of Oculomotor nerve are common and may spare the
extra-occular muscles
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4- Trochlear Nerve
Component:   Motor Nerve

Origin:

Trochlear Nerve Nucleus:

                                      It is situated in the Anterior part of the gray matter that surrounds the
cerebral aqueduct of the midbrain just inferior to oculomotor nerve
...

It immediately decussate with the nerve of the opposite side
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Then enters the orbit through the superior orbital fissure
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Functions:

           It enables movement in the eye's superior oblique muscle
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  5-

Trigeminal Nerve

Component:   Mixed Nerve

Trigeminal Nerve Nuclei:

1
...
Spinal Nucleus
3
...
Motor Nucleus 

Main Sensory Nucleus:

Location:

           It lies in the Posterior part of the pons, lateral to the Motor Nucleus
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Spinal Nucleus:

Location:

           It continues superiorly with the main Sensory Nucleus in pons and extend
inferiorly to the medulla oblongata and spinal cord upto the C2 segment
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Mesencephalic Nucleus:

Location:

           It is located in the lateral part of the gray matter around the cerebral
aqueduct and extends to pons
...

Motor Nucleus:

location:

        It is located at the pons medical to Main Sensory Nucleus
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Muscles of Mastication:
Mylohyoid


Digastric
Tensor Tympani 

Origin/Pathway:
Sensory Component:

                    Sensory fibers of pain, temperature, pressure goes to the trigeminal
ganglion from face and from the larger root
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It also recieves fibers from the reticular formation
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 Now the trigeminal nerve leaves the anterior aspect of the pons as a small
motor root & large sensory root
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> It divides into three Nerves
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Branches:

A-  Ophthalamic Nerve:

It is purely sensory nerve
...


Sub-branches:
1
...
Lacrimal Nerve: (recieve sensation from eye)

3
...

It leaves the skull through foramen rotundum
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Infraorbital: (receive the sensation from the lower part of orbital cavity)
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Supraorbital: (receive the sensation from the upper part of mouth/face)
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Its opening the skull from foramen ovale
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Muscular Branches: (Motor Branch)
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2
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            It supplies the lower part of skin
area        over chin and lower part of face
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Lingual Nerve:                                                     It supplies the tongue
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Motor Components:                                              Examine the teeth, jaws,
clavicle movement
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Pain is felt most commonly over the skin areas innervated by the mandibular and
maxillary divisions of the trigeminal nerve, only rarely is pain felt in the area supplied
by tha Ophthalamic division
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It receives corticonuclear fibers from both cerebral aqueduct
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It recieves fibe
3
...

The fibers enter the anterior surface of brainstem at the lower border of pons
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=One branch entering the Posterior cochlear nucleus 

=Other branch entering the anterior cochlear nucleus
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Clinical Problems:

           Damage to cochlear nerve results the deadness, tinnitus
...
Rinne's Test
2
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They runs laterally in the Posterior cranial fossa 
Then enter the internal acoustic meatus with the facial nerve
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9- Glossopharyngeal Nerve

Component: Mixed Nerve

Glossopharyngeal nerve nuclei:

1
...
Parasympathetic Nucleus
3
...

Parasympathetic Nucleus:

•It is also called the inferior salivatory nucleus
...


•It recieves efferent fibers to parotid glands
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•It takes taste sensation in thalamus
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It passes b/w the olive and the inferior cerebellar peduncle
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The nerve accompanies with the internal carotid artery & internal jugular vein
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Motor Component: terminate by supplying the muscles of pharynx
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Functions:
It supplies the stylopharyngeus muscles
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Pathology:

         Damage to the nerve can result in a loss of taste, particularly bitter and sour
flavors, and trouble swallowing
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10- Vagus Nerve

Component: Mixed Nerve

Longest Nerve
It extend from brain to spinal cord
...
The Main Motor Nucleus 
2
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The Sensory Nucleus 

Main Motor Nucleus:

It lies deep in the reticular formation of the medulla oblongata
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It supply the constrictor muscles of the pharynx and the intrinsic muscles of
larynx
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It recieves afferent fibers from hypothalamus
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Main Sensory Nucleus:

It is the lower part of the nucleus of the tractus solitarius
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It takes sensation from pharynx, palate and mouth cavity
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The nerve passes laterally through the Posterior cranial fossa and leaves the
skull through the jugular foramen
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Superior Ganglion: within the jugular foramen
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Below the Inferior Ganglion, the cranial root of accessory nerve joins the vagus
nerve
Its distributed mainly in its pharyngeal and recurrent laryngeal branches

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