Lecture 2: Cranial Nerves Flashcards Preview

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

What is the general tract of CN IV?

A
  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
2
Q

Cranial Nerve II

What is this nerve?

What is its CNS origin?

What is its distribution?

A

Optic Nerve

Diencephalon

Retina of eye

3
Q

What is the general tract of CN X?

A
  1. Emerges from medulla
  2. Exit cranium through jugular foramen
4
Q

Cranial Nerve IV

What is this nerve?

What is its CNS origin?

A

Trochlear Nerve

Midbrain: Pontine (Abducens) Nucleus

5
Q

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

A

Problems with parasympathetic division

Horner’s syndrome symptoms

6
Q

What is the general tract of CN VII?

A
  1. Emerges from the pontine-medullary jxn
  2. Cross posterior cranial fossa to exit skull via internal acoustic meatus
  3. Run in facial canal and exit via stylomastoid foramen
  4. Pass through the parotid gland
7
Q

What opening does the CN V2 exit from?

A

Foramen rotundum

8
Q

What CN is affected in Bell’s Palsy?

What occurs as a result?

A

CN VII

Inability to use facial muscles

9
Q

Cranial Nerve I

What is this nerve?

What is its CNS origin?

What is its distribution?

A

Olfactory Nerve

Telencephalon

Olfactory mucosa of nose

10
Q

What happens if CN III is damaged?

A
  • 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!!

11
Q

What is the general tract of CN XII?

A
  1. Emerges from the medulla
  2. Exits skull via hypoglossal canal
  3. Travels with cervical plexus
  4. Cross occipital A.
  5. Enter oral cavity
12
Q

What is the function of CN V2?

A

Sensory Afferent

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

13
Q

What are the divisions of CN V?

A

CN V1: Ophthalmic Branch of the Trigeminal Nerve

CN V2: Maxillary Branch of the Trigeminal Nerve

CN V3: Mandibular Branch of the Trigeminal Nerve

14
Q

What is the function of CN XII?

What happens if this nerve is damaged?

A

Somatic Efferent: Supplies all intrinsic and extrensic muscles of the tongue except Palaoglossus Muscle.

If damaged, can lead to difficulty swallowing and speaking.

15
Q

Cranial Nerve III

What is this nerve?

What is its CNS origin?

A

Oculomotor Nerve

Midbrain/Mesencephalon: Oculumotor and Edinger Westphal nuclei

16
Q

Cranial Nerve IX

What is this nerve?

What is its CNS origin?

A

Glossopharyngeal Nerve

Medulla

Derivatives of 3rd pharyngeal arch

17
Q

What is the function of CN I?

What happens if this nerve is damaged?

A

Special Sensory: smell/olfaction

If damaged, can cause anosmia

18
Q

Simply put, where are the 12 cranial nerves located?

Use Rule of 4s

A

Cranial Nerves 1-4 are above the pons

Cranial Nerves 5-8 in the pons

Cranial Nerves 9-12 in the medulla

19
Q

What is the function of CN VII?

A

Special Visceral Efferent (Branchial Motor)

  • Innervates Stapedius muscle (in ear)
  • Innervates Stylohyoid, Posterior belly of Digastric Muscle
  • Innervates muscles of facial expression

General Visceral Efferent

  • Innervates lacrimal, submandibular, and sublingual glands
  • Innervates mucous membrane of nose
  • Innervates hard and soft palates

General Sensory Afferent

  • Skin of concha of auricle, small patch behind ear
  • Helps CN V3 with acoutsti meatus and external tympanic membrane

Special Sensory Afferent

  • Senses taste from anterior ⅔ of tongue
    • CN V3 does sensation!
  • Senses taste from hard and soft palates
20
Q

What is the function of CN VIII?

What happens if this nerve is damaged?

A

Special Sensory:

  • Cochlea: Auditory Information
  • Semicircular Canals: Balance Information

If there is damage, can lead to loss balance, nausea, vomitting, dizziness, and deafness

21
Q

What direction will the tongue deviate if there is a lesion of the hypoglossal nerve on one side?

A

Towards the lesion

May atrophy

22
Q

Cranial Nerve V

What is this nerve?

What is its CNS origin?

A

Trigeminal Nerve

Pons

Derivatives of 1st pharyngeal arch

23
Q

Cranial Nerve VIII

What is this nerve?

What is its CNS origin?

What is its distribution?

A

Vestibulocochlear Nerve

Pontine Medullary Junction

Internal ear

24
Q

Cranial Nerve VII

What is this nerve?

What is its CNS origin?

A

Facial Nerve

Pons

Derivatives of 2nd Pharyngeal Arch

25
Q

What are the four parasympathetic ganglion?

A

Cilliary

Pterygopalatine

Otic

Submandibular

26
Q

What CN is involved in closing the eye?

A

CN VII - Facial N.

27
Q

What is the general tract of CN VI?

A
  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
28
Q

What is the tract of the CN V1 division?

A

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

29
Q

What is the general tract of CNII from the brain?

A
  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
30
Q

What does the parasympathetic motor function of CN VII?

A

Facial Nerve

-Innervates lacrimal gland of the eye, submandibular and sublingual salivary gland

31
Q

If CN X is damaged, what conditions can occur?

A
  • Larnyx issues: hoarseness or loss of voice
  • Difficulty Swallowing
32
Q

What does the parasympathetic motor function of CN X?

A

Vagus Nerve

-Innervates smooth muscles and glands of heart, lungs, larynx, trachea, and most abdominal organs

33
Q

What does the parasympathetic motor function of CN IX?

A

Glossopharyngeal Nerve

-Innervates parotid salivary gland

34
Q

Where is CN I located?

Where does it synapse onto?

A

Olfactory organ through cribiform plate to synapse onto Olfactory bulb

35
Q

What is the function of CN VI?

What happens if this nerve is damaged?

A

Somatic Motor: Lateral Rectus Muscle (abducts eye)

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

36
Q

What nucleus do the parasympathetic fibers of CN IX arise from?

A

Inferior Salivatory nucleus

37
Q

What cranial nerves go through the superior orbital fissure?

A

CN III, IV, V1, VI

38
Q

Cranial Nerve VI

What is this nerve?

What is its CNS origin?

A

Abducens Nerve

Pontine Medullary Junction

39
Q

What is the function of CN XI?

What happens if this nerve is damaged?

A

Special Visceral Efferent (Branchial Motor): Supplies SCM and Trapezius muscles

If damaged, can lead to difficulty elevation shoulder or turning head to opposite side

40
Q

Cranial Nerve X

What is this nerve?

What is its CNS origin?

What is its distribution?

A

Vagus Nerve

Medulla/Myelencephalon

Derivatives of the 4th pharyngeal arch

41
Q

What is the function of CN IV?

What happens if this nerve is damaged?

A

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

42
Q

What is the function of CN II?

What happens if this nerve is damaged?

A

Special Sensory: vision

If damaged, can cause anopsia (visual defects)

43
Q

What is the sympathetic motor function of CN III?

(What muscles is it innervating?)

A

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
44
Q

What is the function of CN X?

A

Special Visceral Efferent (Branchial Motor)

  • Innervates most of the striated muscles of pharynx, tongue, and larnyx

General Visceral Efferent

  • Innervates smooth muscles and glands of pharynx, larynx, thoracic and abdominal viscera

Visceral Sensory Afferent

  • Carries sensation from larynx, pharynx, esophagus, thoracic and abdominal viscera
  • Sensation from stretch receptors and chemoreceptors of aortic arch

General Sensory Afferent

  • Sensation from skin at back of ear and external acoustic meatus
  • Sensation from external surface of tympanic membrane and pharyx
    *
45
Q

What is the general tract of CN XI?

A
  1. Emerges from the spinal cord
  2. Enters cranium through foramen magnum
  3. Exit skull through jugular foramen
46
Q

What is the general tract of CN IX?

A
  1. Emerges from medulla
  2. Exit cranium through jugular foramen
  3. Pass b/w superior and middle pharyngeal constrictors
  4. Enter oral cavity
47
Q

What is the function of CN V1?

A

Sensory Afferent

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

48
Q

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

A

Trochlear Nerve (CN IV)

49
Q

What is the function of CN V3?

A

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
50
Q

Which direction does the uvula deviate if there is a lesion on CN X?

A

Away from the side of the lesion

51
Q

What opening does the CN V3 Mandibular exit from?

A

Foramen Ovale

52
Q

What is the parasympathetic motor function of CN III?

(What muscles is it innervating?)

A

Visceral Motor Functions

  • Innervates sphincter pupillae muscle (constrictor)
  • Contracts cilliary muscle to make muscle more round and relaxed (good with near vision)
53
Q

What is the function of CN IX?

A

Special Visceral Efferent (Branchial Motor)

  • Innervates stylopharyngeus muscle

General Visceral Efferent

  • Innervates otic ganglion: stimulates parotid gland

Visceral Sensory Afferent

  • Carries sensation from carotid body and sinus

General Sensory Afferent

  • Sensation to posterior third of tongue
  • Sensation to skin of external ear and internal surface of tympanic membrane

Special Sensory Afferent

  • Senses taste from posterior third of tongue
54
Q

Cranial Nerve XI

What is this nerve?

What is its CNS origin?

What is its distribution?

A

Spinal Accessory Nerve

Superior Spinal Cord

Superficial layer of neck

55
Q

What nucleus do the parasympathetic fibers of CN VII travel with?

A

Superior salivatory nucleus

56
Q

What is the general tract of CN VIII?

A
  1. Enter skull via interal acoustic meatus
  2. Enter brainstem on pontine-medullary jxn
  3. Vestibular - innervate utricle and saccule; Cochlear innervates cochlea
57
Q

Cranial Nerve XII

What is this nerve?

What is its CNS origin?

What is its distribution?

A

Hypoglossal Nerve

Medulla/Myelencephalon

Muscles of tongue

58
Q

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

A
  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