Cranial Nerves Flashcards
Name the 4 eye related cranial nerves
- opticus
- occulomotorius
- Abbducens
- Trochlear nerve
Name all cranial nerves in order
I. Olfactorial
II. Optical
III. Occulomotorius
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII. Vestibulo-cochlear
IX. glossopharyngeal
X. Vagal
XI. Accessorius
XII. Hypoglossus
What CNs are usually affected by neurinoma?
CN VIII
CN VII
CN V
What is the somatosensory branch of CN VII called?
Nervus intermedius
Where does CNVII originate?
*In the pontomedullary sulcus,
*1-2 mm anterior to CN VIII,
*just anterior to foramen Luschka
*Anterior to a l?ft of choroid
* 4mm cephalate to CN IX
What is the geniculate nucleus to CN VII?
What nerve is running between SCA and PCA?
CN III (Occulomotorius)
What is geniculate neuralgia?
nerve pain from n. intermedius.
What is relayed by n.intermedius?
Its a somatosensory branch of CN VII.
What are symtoms of geniculate neuralgia?
- Otalgia - Ice pick sensation in the ipsilateral ear.
- prosopalgia - Deep pain in the orbit, post nasal and palate
+ salivation, bitter taste, tinnitus, vertigo
Trigger points are common.
How much (approx %) of the facial nerve is myelinated and innervate the facial expression?
70%
What type of neurons are the facial nerve that is not myelinated motornerves?
- somatosensory and *secretomotor - make up the nervus intermedius.
In what 3 locations are CN VII located in the brainstem?
- motor nucleus of the facial nerve
- superior salivatory nucleus
- tractus solitarius
Where does fibers influencing emotional facial expression arise?
In thalamus and Globus Pallidus.
Are facial expressions caused by emotional movement affected by cortical lesions of the facial motorcortex (supranuclear pyramidal lesions)?
No, they are initiated in the Thalamus and Globus Pallidus.
From where does the facial nucleus recieive afferent input?
- Motor cortex via internal capsule (pyramidal - corticobulbar tract)
- Thalamus/globus pallidus (extrapyramidal)
- Afferents from the trigeminal nerve and nucleus.
- Afferents from the acoustic nuclei
What reflex is due to input from the acustic nucleus to the facial nerve nuclei?
The stapedial reflex response to loud noices.
Name a trigeminofacial reflex.
The corneal reflex.
Why is an interplay between the pyramidal and extrapyramidal facial systems important?
It accounts for resting tone and stabilizes the motor responses. Masked face of Parkinsonism is associated to destruction of extrapyramidal pathways
What CN are located in the midbrain, pons and medulla respectively?
midbrain: CN I-IV
pons: CN V-VIII
medulla: CN IX-XII
Mnmonic for the 12 CN
-Oh oh oh, to touch and feel very good velvet, -A Heaven!
Mnemonics for “Types of nerves” - in numerical order.
Some Say Money Matters, But My Brother Says Big Brains Matter Most
S=sensory
M=motor
B=both
All cranial nerves except two have nuclei. Where are they situated? And what do the two other have?
Spinal cord: Accessory nucleus
Forebrain: Olfactory and Optic centres - These two doesnt have nuclei but instead their cell bodies are in the olfactory area of the roof of the nasal mucosa and in the retina of the eye.
Brainstem: All the rest.
Describe the path of smell from the nose
Olfactory nerve in nasal cavity
Through Cribriform plate in the Ethmoidal bone.
Terminate in the Olfactory bulb.
Continues as the Olfactory tract.
Disperse and end in the olfactory cortex: Piriform cortex, Amygdala, Enthorinal cortex.
Where are the the cell bodies of the CN I found?
NOT in a nucleus but in the nasal mucosa that covers the roof of the nasal cavity. Called the Olfactory area.
What three CN are most often encountering neurinoma?
- Vestibulopcpchlearis (acusticus) CN VIII
- Facial CN VII
- Trigeminal CN III
In regard to cranial nerves, what happen in a lower midbrain lesion above the level of facial nucleus?
Contralateral paresis of the face and muscles of extremeties, ipsilateral ABDUCENS muscle paresis. Ipsilateral STRABISMUS (skelögdhet) (esotropia= medialt riktad fixation).
IF the lesion is far lateral, it might include emerging facial fibres and a peripheral ipsilateral facial paralysis may be apparent.
Count up the 12 CN
CNI- ollfactorius -S
CNII- opticus -S
CNIII - occulomotorius - M (+ parasympathetic from Edinger Westphal and sympathetic fibres in the cavernous sinus from the superior cervical ganglion)
CNIV - trochearis - M
CNV- Trigeminal -B
CNVI -Abducens -M
CNVII - Facialis -B
CNVIII-Vestibulocochlearis -S
CNIX-glossopharyngeus -B
CNX- Vagus -B
CNXI- Accessorius -M
CNXII- hypoglossus -M
Ange de 4 ögonCN o deras uppgift
CN II - opticus -syn
CN III - occulomotorius Allt utom snett nedåt och utåt sidan.
CN IV - nedåt utåt
CN VI - Sidan
Var utträder CN IV?
fissura orbitalis superior
What are the two nucleus that contribute axons to the CN III?
- Occulomotor nucleus
- Edinger Westphal nucleus.
What does the edinger westphal nucleus contribute with?
Parasympathetic fibres.
Where does the parasympathetic fibres from eding westphal synapse?
At the ciliary ganglion.
Where in the brain is the occulomotorius nucleus lie?
Its just anterior to the periventricular grey matter of the cerebral aqueduct in the same level as the superior colliculus.
What course does the occulomotorius nerve take from Edinger westphal and oculomotor nucleus to the cavernous sinus?
Through tegmentum, red nucleus and medial aspect of substantia nigra.
Then through medial aspect of the cerebral peduncle, enter the interpeduncular cistern. Then forward below PCA and above SCA - WHERE IT MIGHT GET COMPRESSED BY PCA ANEURYSM. Then pierces the dura mater and enter the cavernous sinus.
Describe the course through the cavernous sinus for CN III
Its located uppermost, above the trochlear nerv, in the lateral wall of the sinus. Through the cavernous sinus it receives sympathetic fibres from the carotid plexus originating from the superior cervical ganglion.
Where does CN III enter the orbit?
Through the superior orbital fissure.
What structures does enter the orbit through the superior orbital fissure in the tendinous ring?
- CN III (split in superior and inferior division)
- Between the split CNIII divisions, the Nasociliary nerve is running.
- Below these three runs the abducens nerve (CN VI)
What is the nasociliary nerve?
A branch of the opthalmic division of the trigeminal nerve.
Hur kan Horners syndrom uppkomma traumatiskt?
Vid skada på ganglion stellatum på halsen precis framför tvärutskottet på C7, precis under a.subclavia.
Eller skador på Carotis där ovanför, ex dissektion. Ger skada på sympatiska fibrer som ansluter sig till n. Occulomotorius i sinus cavernosus.
Symtom på Horners syndrom
Ipsilateral:
Mios (liten pupill) men reaktiv.
Lätt ptos
Anhidros ansikte
Hettande och torr aniktshalva
What nerve provides motor and sensory innervation of the larynx?
Vagus nerve
Which CN innervates the musckes of the tongue?
Hypoglossal nerve
Which cranial nerve can cause paralysis of the stapedius muscle (sensitivity to loud noises, ringing, fullness and pain in the ear)
Facial nerve
Name 3 branches of the opthalmic nerve
- Nasociliary nerve
- Frontal nerve
- Lacrimal nerve
Describe Bells paresis
- droopy eyelid
- droopy corner of the mouth
- inability to close the eye
- increased sensitivity to noice
- loss of taste in the anterior 2/3 of the mouth
What is CN 9 called?
Glossopharyngeus.
What nerves enter the brainstem by the cerebellopontine angle?
The facial nerve and the vestibulocochlear nerve
What nerve is responsible for taste in the anterior 2/3 of the tounge?
Chorda tympani (from the facial nerve)
What nerve innervate the superior oblique muscle?
Trochlear nerve
A pathological jaw jerk reflex indicate a lesion of which cranial nerve?
The Trigeminal nerve
What is the jaw jerk reflex?
Its a stretch reflex of the masseter muscle, innervated by the motor component of the CN V.
It is basically only seen if a upper motorneuron lesion ( in this case of CNV) is present. - When tapping the mandible just under the lip with the mouth slightly open, the masseter will jerk the mandible upwards.
What CN?:
Difficulty swallowing, slurred seech, tongue deviation to one side.
CN XII - Hypoglossus
What is postoperative Freys syndrome?
Damage to the auricotemporal nerve so that it starts innervating sweatglands instead of salivary glands.
Which CN gives rise to the auricotemporal nerve?
CN V3. The mandibular nerve
What muscles are innervated by the oculomotor nerve?
- superior and inferior rectus muslce.
- The medial rectus muscle
- The inferior oblique muscle
What CN nerve, innervating the posterior 1/3 tongue with taste and general sensation can be damaged in tonsillectomy?
The Glossopharyngeal nerve (CN IX)
There are actually 2! cranial nerves responsible for sweet taste sensation. Which?
Chorda Tympani (facial)
Glossopharyngeal
Where is nucleus nervi abducentis located?
In Pons.
Through what facial bones are the olfactory nerve passing?
- Lamina cribrosa and
- Ethmoid bone
Describe the clinical symtoms of a corneal reflex
An involuntary blinking of the eyelids secondary to touch of the cornea.
Describe the neurology behind the corneal reflex.
Afferent limb: Opthalmic nerve.
Efferent limb:
Which nerve run through the internal acoustic meatus but doesnt provide innervation to any of the structures in the inner ear?
Facial nerve
Which cranial nerves run through the superior fissure of the orbit?
CN III, CN IV, CN VI and CNV1.
The vestibule, (vestibulum auris) contains small openings in the side adjacent to the internal meatus that are conduits for branches - Of what nerve?
The vestibulocpchlear nerve
Which nerve is this?
* Taste posterior 1/3 of tongue
* sensation of tonsils, pharynx, middle ear
* motorfibers to stylopharyngeus muscle
Glossopharyngeal nerve
What nerve provide sensory innervation of the INNER ear?
The vestibulocochlear nerve
Branches of what nerve innervate the teeth of maxilla?
The maxillary nerve
Which nerve exits the brainstem from the middle if the pons?
The Trigeminal nerve
what is CN XII called?
the hypoglossal nerve
Which cranial nerve is the only cranial nerve that exits the brainstem on its dorsal side?
The Trochlear nerve
Which CN has the sensory innervation of the middle ear?
The glossopharyngeal nerve
What nerve innervates the muscles of mastication+
Mandibular nerve
Which nerve is responsible for the gag-reflex, sensory innervation of the posterior 1/3 of the tongue and the pharynx?
Glossopharyngeal nerve
Which nerve found in the orbit is sheathed in all three meningeal layers (dura, arachnoid, and pia mater)?
The optic nerve
What CN innervates the SCM and trapezius muscles?
Accessory nerve
Which cranial nerves provide sensory branches to the pharyngeal plexus to supply the pharynx?
- Maxillary nerve
- Vagus nerve
- Glossopharyngeal nerve
Which nerve provides the motor and sensory innervation of the larynx?
Vagus nerve
The nasociliary, the Lacrimal and the frontal nerve all belongs to a cranial nerve. Which?
V1
Which cranial nerve is responsible for special visceral afferent innervation of the root of the tongue (radix linguae)?
- Glossopharyngeus nerve
- Vagus nerve (a very small fiber content, carried through the superior laryngeal branch. Its limited to an area proximal to epiglottis
Which cranial nerves have their nuclei in Pons?
- Vestibulocochlear nerve
- Facial nerve
- Abducens nerve
- trigeminal nerve
