Lecture 2: Cranial Nerves Flashcards Preview

Year 1: 05. Neuro Exam 1 > Lecture 2: Cranial Nerves > Flashcards

Flashcards in Lecture 2: Cranial Nerves Deck (58)
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1

What are the four parasympathetic ganglion? 

Cilliary 

Pterygopalatine

Otic

Submandibular 

2

Cranial Nerve I

What is this nerve?

What is its CNS origin?

What is its distribution?

Olfactory Nerve

Telencephalon

Olfactory mucosa of nose

3

Where is CN I located?

Where does it synapse onto?

Olfactory organ through cribiform plate to synapse onto Olfactory bulb

4

What is the function of CN I?

What happens if this nerve is damaged?

 

Special Sensory: smell/olfaction

If damaged, can cause anosmia

5

Cranial Nerve II

What is this nerve?

What is its CNS origin?

What is its distribution?

Optic Nerve

Diencephalon

Retina of eye

6

What is the general tract of CNII from the brain?

  1. Optic nerve fibers arise from ganglion cells in retina
  2. Enters cranium via optic foramen 
  3. Nerves unite at optic chiasm
  4. Synapse onto lateral geniculate bodies of thalamus

7

What is the function of CN II?

What happens if this nerve is damaged?

 

Special Sensory: vision

If damaged, can cause anopsia (visual defects)

8

What cranial nerves go through the superior orbital fissure?

CN III, IV, V1, VI

9

Cranial Nerve III

What is this nerve?

What is its CNS origin?

 

Oculomotor Nerve

Midbrain/Mesencephalon: Oculumotor and Edinger Westphal nuclei 

 

10

What is the general tract of CN III from the brain?

  1.  Exits midbrain through dura lateral to diaphragma sellae
  2. Runs in lateral wall of cavernous sinus
  3. Enters through superior orbital fissure into orbit

11

What is the parasympathetic motor function of CN III?

(What muscles is it innervating?)

Visceral Motor Functions

-Innervates sphincter pupillae muscle (constrictor) 

-Contracts cilliary muscle to make muscle more round and relaxed (good with near vision)

12

What is the sympathetic motor function of CN III?

(What muscles is it innervating?)

Somatic Motor Functions

  • Innervates intrinsic eye muscle: Elevates eyelid
    • Levator Palpebrae Superioris Muscle
  • Innervates extrinsic eye muscle: Move eyeball
    • Superior Rectus Muscle
    • Medial Rectus Muscle
    • Inferior Rectus Muscle
    • Inferior Oblique Muscle

 

13

What happens if CN III is damaged?

 

  • Ptosis (upper eleyid droop)
  • Paralysis of eye muscles leading to strabismus
    • eyes are not parallel and deviated properly
  • Diplopia (double vision)
  • Difficulty with focus
    • Dilated pupil

Gaze will be down and out!!

14

What presents first if CN III is compressed by an aneurysm?

Problems with parasympathetic division 

Horner's syndrome symptoms

15

Cranial Nerve IV

What is this nerve?

What is its CNS origin?

 

Trochlear Nerve

Midbrain: Pontine (Abducens) Nucleus

 

16

What is the general tract of CN IV?

  1. Exit dorsal surface of midbrain and pierce dura mater at margin of entorium cerebelli
  2. Run in lateral wall of cavernous sinus
  3. Enters orbit via superior orbital fissure

17

What is the only nerve that exits on the dorsal surface of the brainstem?

Trochlear Nerve (CN IV)

18

What is the function of CN IV?

What happens if this nerve is damaged?

Somatic Motor: Innervates Superior Oblique Muscle (depresses, internally rotates, and abducts the eye)

If damaged, can lead to limited downard movement of eye, strabismus, and diplopia 

19

Cranial Nerve VI

What is this nerve?

What is its CNS origin?

 

Abducens Nerve

Pontine Medullary Junction

 

20

What is the general tract of CN VI?

  1.  Emerge from brainstem at pontine-medullary junction
  2. Traverse pontine cistern and pierce dura covering the clivus
  3. Run in cavernous sinus near Internal Carotid A.
  4. Enters orbit via superior orbital fissure

21

What is the function of CN VI?

What happens if this nerve is damaged?

Somatic Motor: Lateral Rectus Muscle (abducts eye)

If damaged, can lead to paralysis of lateral eye movements and diplopia 

22

Cranial Nerve V

What is this nerve?

What is its CNS origin?

 

Trigeminal Nerve

Pons

Derivatives of 1st pharyngeal arch

23

What are the divisions of CN V?

CN V1: Ophthalmic Branch of the Trigeminal Nerve

CN V2: Maxillary Branch of the Trigeminal Nerve

CN V3: Mandibular Branch of the Trigeminal Nerve 

24

What is the tract of the CN V1 division?

Trigeminal cave => Cavernous sinus => Superior orbital fissure => orbit

25

What is the function of CN V1?

Sensory Afferent

Sensation to cornea, skin of forehead and scalp, upper eyelid, the bridge to the point of nose, and nasal cavity

26

What opening does the CN V2 exit from?

Foramen rotundum

27

What is the function of CN V2?

Sensory Afferent

Skin of face, lower eyelid, cheek, upper lip, maxillary teeth, mucosa of nose, maxillary sinus

28

What opening does the CN V3 Mandibular exit from?

Foramen Ovale

29

What is the function of CN V3?

Sensory Afferent

  • Anterior 2/3 of the tongue
  • Skin of mandible, lower lip, mandibular teeth, TMJ joint, part of oral mucosa

Visceral Efferent (Branchial Motor)

  • Innervates muscles of mastiation
  • Innervates mylohyoid, anterior belly of digastric muscle, tensor tympani, and tensor veli palatini 

30

Cranial Nerve VII

What is this nerve?

What is its CNS origin?

 

Facial Nerve

Pons

Derivatives of 2nd Pharyngeal Arch