Exam3Lec6CranialNerves Flashcards

1
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

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olfactory and optic are NOT in brain stem, it’s in the brain

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2
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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3
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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4
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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5
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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6
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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7
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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8
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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9
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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10
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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11
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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12
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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13
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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14
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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15
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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16
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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17
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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18
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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19
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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20
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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21
Q

What is the innervation for the trigeminal nerve branches>?

A

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

22
Q

V-3 Mandibular branches off to which nerves?

A

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

23
Q

The trigeminal nerve provides sensory innervation to which structures?

A
  1. face
  2. scalp
  3. eye (orbit)
  4. paranasal sinus
  5. anterior 2/3 tongue (sensory NOT taste)
  6. mouth floor + oral cavity (teeth, gums, etc)
  7. nasal cavity + nasopharynx
  8. external ear

dura mater too, but we dont care abt her

24
Q

The trigeminal nerve provides motor innervation to which structures?

A
  1. Muscles of mastication
    -temporalis
    -masseter
    -medial + lateral pterygoids
  2. Digastric m. -> ant belly only
  3. Mylohyoid m.
  4. Soft palate (mouth) –> tensor palati
  5. Internal ear–> tensor tympani
25
Q

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

A

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)

26
Q

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

A

If the left abducens n. is affected –>left eye is medial
If the right abducens n. is affected –> right eye is medial

high yield

27
Q

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

A

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

28
Q

What is Bell’s palsy?

A

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)

cannot lift corner of mouth up or elevate top lip

29
Q

What is the sensory innervation of the facial nerve?

facial n=mixed–> sensory + motor innervation

A
  1. ant 2/3 tongue–> taste
  2. Lacrimal gland (parasymp)
  3. Submandibular gland (parasymp)
  4. Sublingual glans (parasymp)
30
Q

What is the motor innervation of the facial nerve?

A
  1. muscles of facial expression
  2. stapedius (middle ear)
  3. digastric m –> post belly only
  4. stylohyoid m.
31
Q

Do the facial expression nerves go to the parotid gland?

A

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

32
Q

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

A

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

33
Q

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

A

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

34
Q

Where does the Glossopharyngeal nerve (CNIX) enter?

A

enters the skull via jugular foramen (post. fossa)

35
Q

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

A

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

Motor:
stylopharngeus m. (pharynx)

36
Q

Where does the vagus nerve (CNX) enter?

A

enters the skull via jugual foramen (post fossa)

37
Q

What is the innervation of the vagus n (CNX)

A

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)

38
Q

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

A

enters the skull via jugular formaen (post. fossa)

39
Q

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

A

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

40
Q

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

A

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

41
Q

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

A

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

42
Q

Clinical note

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

A

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

43
Q

tongue innervation

Anterior 2/3 tongue

A

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

high yield

44
Q

tongue innervation

Posterior 1/3 tongue

A

Sensory: glossopharyngeal n. (CN IX)
taste: glossopharyngeal n. (CN IX)

high yield

45
Q

tongue innervation

Base of the tongue

high yield

A

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

46
Q

tongue innervation

Motor innervation

A

hypoglossal n (CNXII)
exception of palatoglossus (vagus n)

high yield

47
Q

What is this pointing to?

A

trochlear nerve

low yield

48
Q

What is this pointing to?

A

optic nerves

low yield

49
Q

What is this pointing to?

A

olfactory bulb

high yield

50
Q

What is this pointing to?

A

optic tract

51
Q

What is this pointing to?

A

oculomotor nerve

52
Q

What is this pointing to?

A

oculomotor nerve