Exam3Lec6CranialNerves Flashcards by Daniella Andre

Q

Name all Cranial nerves

A

I. Olfactory
II. Optic
III.Oculomotor
IV.Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII.Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
XI. Spinal (Accessory)
XII. Hypoglossal

Oh Oh Oh To Touch And Feel Very Good Velvet Ahhh Heaven
olfactory and optic are NOT in brain stem, it’s in the brain

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Q

Which nerves are sensory only, motor only, and mixed?

A

Sensory Only: 1 (smell),2 (sight),8 (hearing)
Motor only: CN 3,4,6,11,12
Both (mixed): CN 5,7,9,10

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Q

What is the axon pathway of the olfactory nerve (CN 1)

A

nasal axons (bipolar neurons)–> cribriform plate–> olfactory bulb–> olfactory n.

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Q

Where does the olfactory nerve enter and what is its innervation?

A

enters via cribriform plate (ant. fossa)
innervation=sensory only

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Q

Where does the optic nerve (CNII) enter, where are the axons formed from, innervation, and visual pathway

A

enters the skull via optic canal (middle fossa)
axons formed from the cells in the retina of the eye (covered by oligodendrocytes in CNS)-This point is low yield
innervation: sensory only
Visual pathway: retina–> optic n. –> visual cortex (brain) this point is low yield

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Q

What is the optic nerve pathway?

A

optic nerve–> optic chiasm–> optic tract–> LGB (thalamus)–> optic radiation–> visual cortex

medial retina crosses @ optic chiasm & lateral retina remains ipsilateral (this means that the lateral stays on the same side)

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Q

What occurs in this CN II visual pathway defect?

Partial defect of right optic n.

A

partial loss of peripheral vision of right eye

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Q

What occurs in this CN II visual pathway defect?

Complete defect of right optic n.

A

total blindess of right eye

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Q

What occurs in this CN II visual pathway defect?

Complete defect of optic chiasm

A

loss of lateral visual field of both eyes

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Q

What occurs in this CN II visual pathway defect?

Complete defect of right optic tract

A

loss or left visual fields in both eyes

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Q

What occurs in this CN II visual pathway defect?

partial defect of right optic tract

A

loss of medial visual field of right eye

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Q

What occurs in this CN II visual pathway defect?

Complete defect of right optic radiation

A

loss of left visual field in both eyes

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Q

What occurs in this CN II visual pathway defect?

Complete defect of right visual cortex

A

loss of left visual field in both eyes

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Q

Where does the Oculomotor nerve (CNIII) nerve enter?

A

enters the orbit (skull) via superior orbital fissue (middle fossa)
runs through cavernous sinus alongside trochlear (CN 4) + abducens (CN6)

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Q

What is the innervation of oculomotor nerve?

A

Motor to the eye–> sup./med./inf. rectus + inf oblique

except for sup. obliquw (CN4) + lateral recuts (CN6)

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Q

What is the parasympathetic innervation for the oculomotor nerve?

A

parasympathetic fibers–> short ciliary nerves–> innervates ciliary muscle + constrictor pupillae–> mediates light + accommodation reflexes

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Q

Where does the trochlear nerve (CN IV) enter?

A

enters the skull via superior orbital fissure (middle fossa)
runs through the cavernous sinus alongside oculomotor (CN 3) + abducens (CN 6)

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Q

Where does the trochlear nerve (CN IV) exit?

A

exit the skull (brainstem) inferiorly to the inferior colliculus
only cranial n. that is crossed before leaving brainstem

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Q

What is the innervation of the trochlear nerve?

A

motor to the eye–> superior oblique m.

trochlear n. palsy can cause torticollis–> affects SCM

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Q

What are the branches of the trigeminal nerve (CN V)

A

V-1: opthalmic-> enters skull via superior orbital fissue (middle fossa)
V-2: maxiallry-> enters skull via foramen rotundum (middle fossa)
V-3: mandobular-> enters skull via formaen ovale (middle fossa

FYI largest cranial nerve

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Q

What is the innervation for the trigeminal nerve branches>?

Study These Flashcards

A

V-1=opthalmic-> sensory only
V-2=maxillary-> sensory only
V-3=mandibular-> sensory + motor

Q

V-3 Mandibular branches off to which nerves?

Study These Flashcards

A

inferior alveolar-> mental n. (sensory) + mylohyoid n. (motor)

Q

The trigeminal nerve provides sensory innervation to which structures?

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A

face
scalp
eye (orbit)
paranasal sinus
anterior 2/3 tongue (sensory NOT taste)
mouth floor + oral cavity (teeth, gums, etc)
nasal cavity + nasopharynx
external ear

dura mater too, but we dont care abt her

Q

The trigeminal nerve provides motor innervation to which structures?

Study These Flashcards

A

Muscles of mastication
-temporalis
-masseter
-medial + lateral pterygoids
Digastric m. -> ant belly only
Mylohyoid m.
Soft palate (mouth) –> tensor palati
Internal ear–> tensor tympani

Where the abducens nerve (CNVI) enter and exit, and what is its innervation?

enters the skull via superior orbital fissue (middle fossa) exists the skull (brainstem) @ the ponto-meduallry junction innervation= moto to the eye--> lateral rectus m. (for eye abduction)

What occurs if the left and tight abducens n. is damaged?

If the left abducens n. is affected -->left eye is medial If the right abducens n. is affected --> right eye is medial | high yield

Where does the facial nerve (CNVII) enter and exit?

enters the skill via internal acoustic meatus (post. fossa) exits the skull @ cerebello-pontine angle w/ vestibulococchlear (CN 8). Then descends through ear (chords tympani), this leaces stylomastoid foramen | low yield

What is Bell's palsy?

paralysis of facial n. -> unable to close eyelid or smile (face droop) muscles of facial expression affected (includes orbicularis oculi, zygomaticus major/minor, levator labii superioris) ## Footnote cannot lift corner of mouth up or elevate top lip

What is the sensory innervation of the facial nerve? ## Footnote facial n=mixed--> sensory + motor innervation

1. ant 2/3 tongue--> taste 2. Lacrimal gland (parasymp) 3. Submandibular gland (parasymp) 4. Sublingual glans (parasymp)

What is the motor innervation of the facial nerve?

1. muscles of facial expression 2. stapedius (middle ear) 3. digastric m --> post belly only 4. stylohyoid m.

Do the facial expression nerves go to the parotid gland?

NO, they cross the parotid gland to go to the muscles of facial expression

Where does the vestibulocochlear nerve (CNVII) enter and what is its innervation?

enters the skill via internal acoustic meatus (post. fossa) innervation= sensory only

What are the two divisions of the vestibulocochlear nerve (CNVII)?

vestibular division- balance + fixation of gaze + acceleration cochlear division= hearing

Where does the Glossopharyngeal nerve (CNIX) enter?

enters the skull via jugular foramen (post. fossa)

What is the innervation of the Glossopharyngeal nerve (CNIX)?

Innervation=mixed --> sensory + motor Sensory: -tympanic membrane + cavity=middle ear -oropharynx -parotid gland (parasympathetic) -post 1/3 tongue --> TASTE Motor: stylopharngeus m. (pharynx)

Where does the vagus nerve (CNX) enter?

enters the skull via jugual foramen (post fossa)

What is the innervation of the vagus n (CNX)

Innervation=mixed--> sensory + motor Sensory: -concha (nasal cavity) -ear= external acoustic meatus + surface of tympanic membrane -larynx-> superior laryngeal + recurrent larygneal nerves Motor: -abdominal + thoracic viscera (parasymp) -muscles of the larynx + pharynx + tongue (palatoglossus only)

Where does the accessory (spinal) nerve ( CNXI) enter?

enters the skull via jugular formaen (post. fossa)

The accessory (spinal) nerve ( CNXI) splits off into what?

2 parts cranial-> enters jugual foramen-> leaves accessory n. to join vagus n. (CN X) spinal -> enters foramen magnum (post. fossa)-> enters jugular formaen to join cranial

What is the innervation and the clinical correlation of the accessory (spinal) nerve ( CNXI) ?

innervation: motor to the neck-> SCM + trapezius Torticollis (Wryneck)= irritation of accessory n. --> spasmodic contraction of SCM

Where does the hypoglossal nerve (CNXII) enter and what is its innervation?

Enters the skull via hypoglossal canal (post. fossa) Innervation = motor to the tongue->genioglossus + hyoglossus + styloglossus m. Last tongue muscle (palatoglossus = vagus n.) | innervation high yield

# Clinical note What occurs if you have damage to the hypoglossal n. (CNXII)?

tongue deviates to the side of paralysis Right hypoglossal n. = tongue pointing to the right Left hypoglossal n. = tongue pointing to the left

# tongue innervation Anterior 2/3 tongue

Sensory: trigeminal n. (CN V) taste: facial n. (CN VII) | high yield

# tongue innervation Posterior 1/3 tongue

Sensory: glossopharyngeal n. (CN IX) taste: glossopharyngeal n. (CN IX) | high yield

# tongue innervation Base of the tongue | high yield

Sensory: vagus n. (CN X) taste: vagus n. (CN X)

# tongue innervation Motor innervation

hypoglossal n (CNXII) exception of palatoglossus (vagus n) | high yield

What is this pointing to?

trochlear nerve | low yield

What is this pointing to?

optic nerves | low yield

What is this pointing to?

olfactory bulb | high yield

What is this pointing to?

optic tract

What is this pointing to?

oculomotor nerve

What is this pointing to?

oculomotor nerve