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Flashcards in head: cranial nerves Deck (48)
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1
Q

where do these cranial nerves originate? CNI , CN II, CN XI

A

I- cerebrum
II- diencephalon
XI- spinal cord

2
Q

olfactory nerve: where are the receptors, cell bodies, central processes and synapse ?

A

Receptors in roof of nasal cavity
Cell bodies in nasal mucosa
Central processes enter cranium via cribriform plate
Synapse in olfactory bulb

3
Q

only CN to enter cerebrum

A

CN I- olfactory

4
Q

Olfactory tracts project to where?

A

Olfactory tracts project to ipsilateral & contralateral anterior temporal lobes

5
Q

CN II: Optic “nerves” are ___ order neurons

Extensions of ________

A

3rd, extensions of diencephalon

6
Q

optic chiasm

A

Medial (nasal) retinal fibers cross & join lateral (temporal) retinal fibers of contralateral eye
Form optic tracts

7
Q

optic tracts

A

R carries fibers from R half of each retina=left visual field
L carries fibers from L half of each retina=right visual field

8
Q

where do the optic tracts project?

A

to thalamus then to occipital lobes

9
Q

oculomotor: CN III - what does it do?

A

Somatic motor-eye/eyelid movement
Visceral motor-constricts pupil, rounds lens (accommodation)
Efferent limb of light reflex

10
Q

CN III originates from two midbrain nuclei

A
  1. Motor-somatic
  2. Accessory/parasympathetic (Edinger-Westphal)-visceral
    To ciliary ganglion
11
Q

oculomotor nerve + CN IV + CN VI course

A

Courses lateral to diaphragm sella, crosses internal carotid

Enters orbit via superior orbital fissure

12
Q

Short ciliary nerves (V1) go where?

A

to sphincter pupillae & ciliary body

13
Q

what is the largest true cranial nerve?

A

CN V (trigeminal)

14
Q

trigeminal nerve: made of how many brainstem nuclei? - how many are sensory and how many motor? which are larger? where does it emerge from?

A

4 brainstem nuclei-3 sensory, 1 motor
sensory (large) & motor (small) roots
pons
*Sensory root has central processes from trigeminal (semilunar) ganglion

15
Q

trigeminal ganglion is ____ to cavernous sinuses

A

lateral

16
Q

do all trigeminal nerve fibers go through the trigem ganglion?

A

NO! sensory do, but Motor root fibers bypass ganglion

–> Blend with V3 in foramen ovale

17
Q

three branches of opthalmic V1 and their subdivisions

A

Lacrimal
Frontal: Supraorbital/supra trochlear
Nasociliary: Long/short ciliary, Infratrochlear

18
Q

afferent limb of sneeze reflex

A

maxillary V2

19
Q

while V2 has 5 branches, which 2 do we care about? what are their subdivisions?

A

Zygomatic: Zygomaticofacial, Zygomaticotemporal
Infraorbital: Anterior superior alveolar

20
Q

what are the 4 ganglia in the head? what nerve carries ALL postgang PSNS?

A
Ciliary
Pterygopalatine
Otic
Submandibular
- Postganglionic parasympathetic from all ganglia carried by CN V branches
21
Q

where does CN VI (abducens) enter to orbit?

A

comes from posterior cranial fossa
Enters at clivus
- enters orbit via SOF

22
Q

which nerve has the longest intradural course?

A

CN VI

23
Q

which CN has the longest interosseus course?

A

CN VII

24
Q

where does the facial nerve enter and exit

A

enter: IAM (facial canal)
exit: stylomastoid foramen

25
Q

where does the facial nerve take a sharp bend?

A

at the geniculate ganglion

26
Q

three interosseus branches of CN VII (facial)

A

Greater petrosal
Nerve to stapedius
Chorda tympani

27
Q

Chorda tympani (of facial nerve) enters infratemporal fossa via ______ _______ to meet with lingual V3

A

petrotympanic fissure

28
Q

what innervates the stapedius (muscle that stabilizes the stapes)?

A

Branch to stapedius from facial nerve CN VII

29
Q

Facial nerve CN VII- exits cranium via what? to become what 5 extracranial branches?

A

stylomastoid foramen

temporal, zygomatic, buccal, marginal mandibular, cervical

30
Q

what do the external branches of facial nerve innervate?

A

Muscles of facial expression
posterior digastric + stylohyoid
Efferent limb of corneal reflex
Orbicularis oculi

31
Q

mandibular V3 supplies what muscles?

A

Mylohyoid
Anterior digastric via Nerve to mylohyoid
Tensor veli palatini
Tensor tympani

32
Q

where do the two branches of vestibulocochlear nerve go? (CN VIII) - where are the cell bodies of each?

A

Vestibular to maculae of utricle & saccule, cristae ampullaris of semicircular canals
Cell bodies in vestibular ganglion

Cochlear to spiral organ of Corti
Cell bodies in spiral ganglion

33
Q

which nerves come from preolivary sulcus of medulla oblongata as rootlets?

A

CN IX, X and XII

34
Q

what are the branches of CN IX glossopharyngeal

A

tympanic, pharyngeal (+ stylopharyngeus), lingual, carotid sinus

35
Q

what reflexes are the vagus nerve involved in?

A

Afferent & efferent limbs of cough reflex
Efferent limb of gag reflex
Efferent limb of carotid sinus reflex

36
Q

what are the C1-C2 fibers that the hypoglossal nerve CN XII carries (but then they depart)

A

Superior root of ansa cervicalis (C1 ± C2)

Nerves to geniohyoid & thyrohyoid (C1)

37
Q

which CNs arrive midline? which more lateral?

A

1-3, 6, 12 emerge near midline

4,5 7-10 emerge more lateral

38
Q

for each cranial fossa, how many foramina in each? what are they?

A

Anterior cranial fossa: 1 foramen - cribiform
I
Middle cranial fossa: 4 foramina - optic canal, SOF, rotundum, ovale
II, III, IV, V (1-3), VI
Posterior cranial fossa: 3 foramina - IAM, jugular foramen, hypoglossal canal
VII, VIII, IX, X, XI, XII

39
Q

CN test I + II

A

CN I-check for air movement through each nostril; patient occludes one nostril; use distinctive odor 10 cm from each nostril
CN II-hand-held or wall Snellen chart for acuity; Ishihara for color; visual fields by confrontation

40
Q

CN test III, IV, VI

A

CN III (autonomic motor)-direct & consensual pupil constriction to light & accommodation
II-afferent, III-efferent
CN III (somatic motor), IV, & VI-ptosis & extraocular movements; follow “H” pattern
LR6 SO4 All Others3

41
Q

CN test V

A
CN V (somatic sensory)-cotton swab to V1, V2, V3 distributions, cotton wisp to cornea (blink)
V-afferent, VII-efferent
CN V (somatic motor)-open/close mouth, palpate temporalis & masseter with clenched teeth
42
Q

CN test VII

A
CN VII (somatic motor)-facial symmetry; look up (forehead wrinkles), close eyelids tight, smile, puff cheeks
CN VII (special sensory)-rarely tested; salt to anterior 2/3 tongue
CN VII (autonomic motor)-rarely tested; dry eyes & mouth
43
Q

CN test VIII

A

CN VIII (cochlear)-rub fingers next to ears
Weber-Rinne for conductive vs. sensorineural
CN VIII (vestibular)-rarely tested
Barany test for vertigo, Romberg test for equilibrium

44
Q

CN test IX/X

A

CN IX/X (somatic sensory/motor)-say “Ahhh”, soft palate rises with midline uvula; gag reflex; phonation
Uvula deviates AWAY from affected side
IX-afferent, X-efferent
CN IX/X (other functions)-rarely tested; dry mouth

45
Q

CN test XI and XII

A

CN XI-turn head, shrug shoulders against resistance
CN XII-stick out tongue
Tongue deviates TOWARDS affected side

46
Q

what is the “convoluted course of visceral motor to otic ganglion? (4)

A
  1. glossopharyngeal Tympanic branch enters middle ear - tympanic plexus near mastoid process
    (Visceral sensory & preganglionic parasympathetics)
  2. tympanic n (CN IX) –> Lesser petrosal n. (of CN VII) into middle cranial fossa
  3. enters infratemporal fossa via foramen ovale
    w/ V3 –> otic ganglion
  4. Postganglionics in auriculotemporal (V3) to parotid gland
47
Q

after the tympanic branch, what are the 3 other branches of the glossopharyngela CN IX?

A

Pharyngeal branch
Lingual Branch
Carotid sinus branch

48
Q

what do the pharyngeal, lingual and carotid sinus branches of CN IX do?

A
  1. Pharyngeal branch: Forms pharyngeal plexus with X on middle pharyngeal constrictor
    Sensory to pharynx; Motor to stylopharyngeus
  2. Lingual branch: General sensation & taste to posterior 1/3 of tongue
  3. Carotid sinus branch: Afferent baroreceptive & chemoreceptive + Carotid massage