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.