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GA - Cranial Nerves Flashcards

1
Q

What is the mnemonic for the cranial nerves?

A 
Ooh - Olfactory N. (CN I)
Ooh - Optic N. (CN II)
Ooh - Oculomotor N. (CN III)
To - Trochlear N. (CN IV)
Touch - Trigeminal N. (CN V)
And - Abducent N. (CN VI)
Feel - Facial N. (CN VII)
Virgin - Vestibulocochlear N. (CN VIII)
Girls - Glosopharyngeal N. (CN IX)
Vagina - Vagus N. (CN X)
And - Spinal Accessory N. (CN XI)
Hymen - Hypoglossal N. (CN XII)
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2
Q

What is CN I?

A

Olfactory N.

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3
Q

What is CN II?

A

Optic N.

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4
Q

What is CN III?

A

Oculomotor N.

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5
Q

What is CN IV?

A

Trochlear N.

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6
Q

What is CN V?

A

Trigeminal N.

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7
Q

What is CN VI?

A

Abducent N.

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8
Q

What is CN VII?

A

Facial N.

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9
Q

What is CN VIII?

A

Vestibulocochlear N.

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10
Q

What is CN IX?

A

Glossopharyngeal N.

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11
Q

What is CN X?

A

Vagus N,

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12
Q

What is CN XI?

A

Spinal ACCESSORY N.

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13
Q

What is CN XII?

A

Hypoglossal N.

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14
Q

What cranial nerves exit from the midbrain?

A

Oculomotor N. (CN III) and Trochlear N. (CN IV)

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15
Q

What cranial nerves exit from the Pons?

A

Trigeminal N. (CN V)

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16
Q

What cranial nerves exit from the Pontene-Medullary Junction?

A

Abducent N. (CN VI), Facial N. (CN VII), and

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17
Q

What cranial nerves exit from the Medulla?

A

Glossopharyngeal N. (CN IX), Vagus N. (CN X), and Hypoglossal N. (CN XII)

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18
Q

What are GSE fibers, and which cranial nerves carry them?

A

General Somatic Efferents - Motor nerve fibers that innervate somatic muscle derived from Somites

  • Specifically, Eye Muscles and Tongue

Oculomotor N., Trochlear N., Abducent N., and Hypoglossal N.

(CNs III, IV, VI, and XII)

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19
Q

What are GVE fibers, and which cranial nerves carry them?

A

General Visceral Efferents - Motor nerve fibers carry parasympathetic signals to smooth muscle, cardiac muscle, and glands

Oculomotor N., Facial N., Glossopharyngeal N., and Vagus N.

(CNs III, VII, IX, and X)

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20
Q

What are SVE fibers, which cranial nerves carry them, and which pharyngeal arch do each cranial nerve innervate?

A

Special Visceral Efferents - Motor nerve fibers that innervate muscles derived from Pharyngeal Arches

Trigeminal N., Facial N., Glossopharyngeal N., and Vagus N.

(CNs V, VII, IX, and X)

CN V: Pharyngeal Arch 1
CN VII: Pharyngeal Arch 2
CN IX: Pharyngeal Arch 3
CN X: Pharyngeal Arches 4 and 6

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21
Q

What are GSA fibers?

A

General Somatic Afferents - Sensory nerve fibers that carry signals from the skin, joint capsule, tendon, and muscle (all structures derived from ECTODERM or mesoderm that developed next to ectoderm)

Can pinpoint exact location of pain

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22
Q

What are GVA fibers?

A

General Visceral Afferents - Sensory nerve fibers that carry signals from visceral structures (derived from ENDODERM or mesoderm that developed next to endoderm)

Can pinpoint pain in a general vicinity

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23
Q

What are SSA fibers and which cranial nerves carry them?

A

Special Somatic Afferents - Sensory nerve fibers that carry signals needed for hearing, balance, and sight

Hearing and Balance:
- Vestibulocochlear N. (CN VIII)

Sight:
- Optic N. (CN II)

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24
Q

What are SVA fibers and which cranial nerves carry them?

A

Special Visceral Afferents - Sensory nerve fibers that carry signals for taste and smell (chemical senses)

Taste:

  • Facial N. (CN VII)
  • Glossopharyngeal N. (CN IX)
  • Vagus N. (CN X)

Smell:
- Olfactory N. (CN I)

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25
What is the function, location and tract of CN I?
Olfactory N. carries Special Visceral Afferent fibers which are responsible for the sense of smell Located in the Olfactory organ at the Superior Concha and the Superior aspect of the Nasal Septum Olfactory N. travel through the Cribriform Plate to the Olfactory Bulbs NOTE: OLFACTORY BULBS ARE NOT CN I
26
What is anosmia?
Loss of sense of smell - Contralateral nostril can compensate for unilateral anosmia - Caused by: Head trauma, viral infections, intracranial lesions, nasal passage obstruction Tested using familiar odors
27
What is CSF Rhinorrhea?
Rhinorrhea is a runny nose If the Cribriform Plate is fractured, and tears the dura, then Cerebrospinal Fluid can leak through the nose Tested by looking for a Halo Sign: - Clear drainage (CSF) separates from bloody drainage forming a Clear fluid halo surrounding a collection of blood at the center of a collection of nasal drainage fluid
28
What is the function and tract of CN II?
Optic N. carries Special Somatic Afferent fibers, which are responsible for vision. Optic nerve fibers arise from ganglion cells in the retina - They then exit the orbit via the Optic canal - Then through the optic chiasm - Then through the optic tract - Synapse in the Lateral Geniculate Body
29
How can a pituitary tumor affect vision?
Pituitary is located inferior to the Optic Chiasm Hypertrophic pituitary can squish the optic chiasm Causes Bitemporal Hemianopia - Loss of vision laterally in both visual fields ALSO: If an anneurism develops in the Internal Carotid Artery at the optic chiasm, the same symptoms can develop
30
What tests do you do for vision after head trauma?
Light and Dark (Is it light or dark?) Finger Counting (how many fingers am i holding up?)
31
What is Snellen's test?
Eye chart 20/20 = Read at 20 feet what normal vision sees at 20 feet 20/80 = Read at 20 feet what normal vision sees at 80 feet
32
What is the visual field test?
Pt covers eye standing in front of examiner Examiner does finger count in all 4 quadrants
33
What is Peripheral Vision Test?
Pt and Examiner stand close, look straight ahead at each other, each cover opposite eyes Examiner extends arm and move fingers while gradually moving hand toward midline
34
What is Pupillary Light Reflex and what nerves are involved?
Flash of light causes pupil to constrict Afferent nerve = Optic N. (CN II) Efferent nerve = Oculomotor N. (CN III)
35
What is the Blink Reflex and what nerves are involved?
When something appears as though it is about to make contact with your face, eyes blink Afferent Nerve = Optic N. (CN II) Efferent Nerve = Facial N. (CN VII)
36
What is the function and tract of CN III?
Oculomotor nerve carries General Somatic Efferent nerve fibers, which are responsible for innervating the following muscles: - Superior Recti, Medial Recti, Inferior recti, Inferior oblique, and Levator Palpebrae Superioris Oculomotor N. also carries General Visceral Efferent nerve fibers, which are responsible for paraympathetic innervation of the Pupil and ciliary muscle Occulomotor nerve: - Leaves the Midbrain - Pierces dura lateral to diaphragma sellae - Runs in lateral wall of cavernous sinus - Enters orbit via Superior Orbital Fissure
37
What is the function and tract of CN IV?
Trochlear N. carries General Somatic Efferent nerve fibers - Responsible for motor innervation to the Superior Oblique muscle of the eye It is the ONLY nerve to exit the DORSAL aspect of the brain stem (Specifically Midbrain) It then pierces dura mater at the margin of the tentorium cerebelli Run in the lateral wall of cavernous sinus Enters the orbit via the Superior Orbital Fissure
38
What is the function and Tract of CN VI?
Abducent N. carries General Somatic Efferents that innervate the Lateral Rectus M. of the eye Abducent nerve emerges from the Pontine-Medullary Junction Then traverses the pontine cistern then pierces dura covering the clivus Then runs in the cavernous sinus near the Internal Carotid A. Then enters the orbit via the superior orbital fissure
39
How do you test cranial nerves III, IV, and VI?
Moves hands in an "H" and then move hands toward face while having patient only move their eyes Trochlear N. (CN IV) innervates the Superior Oblique M. - Causes Eye inferiorly and medially Abducent N. (CN VI) innervates the lateral rectus M. - causes eye to look laterally Oculomotor N. (CN III) innervates the remaining muscles - Superior Rectus M. (eye looks superior and lateral) - Medial Rectus M. (eye looks medially) - Inferior Rectus M. (eye looks Inferior and lateral) - Inferior Oblique M. (eye looks Superior and Medial)
40
How do you test Lavator Palpebrae M.?
Examiner holds eye shit, and asks pt to open eye Levator Palpebrae is innervated by the Oculomotor N.
41
How do you test for Accomodation?
Ask patient to follow your hand with their eyes only as you move your hand toward their face and watch for convergence
42
What are the three components of Accommodation?
Convergence Adjust Lens thickness Pupillary Constriction
43
What is ptosis?
Droopy eye lid Indicates problem with either CN III (Occulomotor N.) or sympathetics
44
What nerve causes eye to close?
CN VII (Facial N.)
45
What is Cavernous Sinus Thrombosis?
When an anneurism causes swelling of vessels nearby cranial nerves, reducing their ability to conduct signals If Posterior Communicating A., Posterior Cerebral A., and Superior Cerebral A. swell, then they can restrict communication through CN III (Occulomotor N.) If Internal Acoustic A. or the Anterior Inferior Cerebellar A. swell, then they can constrict CN VI (Abducent N.)
46
Describe the functions of CN V
CN V (Trigeminal N.) contains Special Visceral Efferent fibers - which innervate muscles derived from the Pharyngeal Arches. CN V SVE fibers innervate muscles derived from Pahryngeal Arch 1 (muscles used for chewing) CN V also contains General Somatic Afferent fibers, which send sensory signals from the Face and Scalp
47
What are the branches of CN V?
CN V (Trigeminal N.) has Three Branches (Tri) V1 = Opthalmic Branch V2 = Maxillary Branch V3 = Mandibular Branch
48
Where does V1 exit the skull?
The Opthalmic Branch of the Trigeminal N. exits the skull through the Superior Orbital Fissure
49
Where does V2 exit the skull?
The Maxillary Branch of the Trigeminal N. exits the skull through the Foramen Rotundum
50
Where does V3 exit the skull?
The Mandibular Branch of the Trigeminal N. exits the skull through the Foraman Ovale
51
What is the function of V1?
The Opthalmic Branch of the Trigeminal N. is responsible for Sensation from the following structures: - Cornea - Skin of the Forehead and Scalp - Upper Eyelid - Part of the nose - Part of the nasal cavity
52
What is the function of V2?
The Maxillary Branch of the Trigeminal N. is responsible for sensation from the following structures: - Skin of face - Lower Eyelid - Cheek - Upper Lip - Maxillary teeth - Mucosa of nose - Maxillary Sinus
53
What is the Function of V3?
The Mandibular Branch of the Trigeminal N. is responsible for sensation from the following structures: - Skin of the mandible - Lower lip - Side of head - Mandibular Teeth - TMJ (temporomandibular joint) - Part of Oral Mucosa - Anterior 2/3 of tongue (NOT TASTE) Also responsible for Motor to mastication muscles
54
How do you test CN V?
OPTHALMIC DIVISION: A) Sensation of Forehead and Nose B) Corneal Reflex (touch cornea with cotton wisp, pt will blink if reflex is functional) - Sensation: CN V1 (Opthalmic Division of Trigeminal N.) - Motor: CN 7 (Facial N.) MAXILLARY DIVISION: A) Cheek sensation MANDIBULAR DIVISION: A) Chin sensation B) Motor - muscles of mastication (have pt clench teeth and feel muscles contract)
55
What is Tic Douloureux?
AKA Trigeminal Neuralgia Something is irritating CN V or one its branches Causes episodes of intense spasmatic pain - Pain can be so severe, people contemplate suicide to end their suffering Can be brought on by something touching the face, talking, eating
56
What are the functions of CN VII?
CN VII (Facial N.) has Special Visceral Efferent fibers that innervate muscles derived the Pharyngeal Arches (CN VII specifically innervates structures derived from Pharyngeal Arch 2; muscles of facial expression) Also has General Visceral Efferent Fibers, which provide parasympathetic innervation to lacrimal (tear) glands, nasal glands, the salivary glands (palatine, submandibular, sublingual) Also has Special Visceral Afferent fibers, which allow for Taste sensation in the anterior 2/3 of the tongue And finally, it has General Somatic Afferent fibers, which provide sensation from the External Acoustic Meatus in the ear
57
What is the tract of CN VII?
Emerges from the Pontine-Medullary Junction Exits through the Internal Auditory Meatus Travels through the Facial Canal Exits through the Stylomastoid Foramen Then passes through the Parotid Gland
58
How do you test for CN VII?
Facial N. Testing: A) Sensation - taste anterior 2/3 of tongue - Have Pt stick tongue out and put sugar on one side and see if they taste it B) Motor: - Upper division - wrinkle forehead or close eye tightly - Lower division - blow, whistle, smile, suck on straw C) Blink Reflex - Optic and Facial D) Corneal Reflex - V1 and facial (good for testing level of anesthesia)
59
What is Bells Palsy?
Idiopathic peripheral facial nerve (CN VII) - Inability to raise eyebrow/ wrinkle forehead on one side - Difficulty closing eye/inability to raise corner of mouth on one side
60
What is the function of CN VIII?
Vestibulocochlear N. carries Special Somatic Afferent fibers which are responsible for specials senses of hearing and equilibrium Cochlear Nerve innervates the cochlea (organ responsible for hearing) Vestibular Nerve innervates the Utricle and Saccule (organs responsible for equilibrium)
61
What is the tract of CN VIII?
Leaves the brain stem from the Pontine-Medullary junction Enters the skull through the Internal Acoustic Meatus
62
How do you test vestibular division of CN VIII?
A) Romberg's Sign - Have Pt stand in a T sign (feet together, arms out to the side) with eyes closed. Positive sign when Pt can't keep balance B) Past Pointing - Finger to nose, first with eyes open, then have Pt close them C) Nystagmus - Abnormal eye movement caused by a vestibulr lesion - Eye jumps from target to target
63
How do you test cochlear division of CN VIII?
Conduction Deafness - impacted wax, otitis media, bony ankylosis, otosclerosis , torn tympanic membrane Whispering or Rubbing fingers - rough assessment of acuteness Rinne Test - Have tuning fork conduct sound through mastoid and then also through air next to the ear lobe. Air conduction should normally last twice as long as bone conduction - Nerve deafness - Rinne test ratio between air and bone conduction is normal, but sound decay times are diminished for both - Conduction Deafness - bone conduction is longer than air conduction Webber Test - Tuning fork on forehead - Sound lateralizes to bad ear
64
What are some clinical correlations of CN VIII?
Irritating Nerves: - Tinnitus (ringing of ears) - Balance disturbance - Nystagmus of the eyes Nerve is Cut: - Deafness Acoustic Neuroma - Benign Tumor development on CN VIII causing compression of the nerve (tinnitus, balance issues) - If tumor develops in the Internal Acoustic Meatus, it can also affect CN VII (Facial N.) which also travels through the Internal Acoustic Meatus
65
What is the Function of CN IX?
CN IX (Glossopharyngeal N.) has various fibers: General Somatic Afferent fibers - Sensation from Ear, External Auditory Canal, and Posterior 1/3 of tongue General Visceral Afferent Fibers - Sensory info from oropharynx and carotid body Special Visceral Afferent fibers - Tast to the posterior 1/3 of tongue General Visceral Efferent fibers - Parasympathetic innervation parotid gland Special Visceral Efferent fibers - Motor to stylopharyngeus muscles (pharyngeal arch 3)
66
What is the tract of CN IX?
Emerges from the medulla Exits cranium through the Jugular foramen Passes between the superior and middle constrictors Enters oral cavity
67
How do you test CN IX?
Tested at the same time as Vagus A) Motor - can be directly tested B) Sensory - taste on posterior 1/3 of tongue - General sensation - gag reflex (overlaps with vagus, therefore not specific)
68
What is glossopharyngeal neuralgia?
Eating/Swallowing will cause intense pain
69
What are the functions of CN X?
Vagus N. has many fibers: General Somatic Afferent - Sensation from external auditory canal and dura General Visceral Afferent - Sensory information from viscera, pharynx, larynx, aortic arch, epiglottis, and base of tongue Special Visceral Afferent - Taste from epiglottis General Visceral Efferent - Parasympathetic innervation to viscera Special Visceral Efferent - Motor to constrictors of pharynx, palatine muscles, and intrinsic muscle of larynx (pharyngeal arches 4 and 6)
70
What is the tract of CN X?
Emerges from the Medulla Exits the cranium through the Jugular Foramen
71
How do you test for CN X?
A) Sensory - gag reflex - not specific since glossopharyngeal also involved B) Motor: - Swallowing reflex - Speech - horseness - Deviation of uvula, say "ahh" (uvula should be centered, if deviated, means issue with vagus n.)
72
What is the function of CN XI?
CN XI (Accessory N.) contains General Somatic Efferents - Motor to Sternocleidomastoid M. and Trapezius M.
73
What is the tract of CN XI?
Emerges from the spinal cord Travels up through the Foramen Magnum Exits cranium through Jugular Foramen
74
How do you test CN XI?
Trapezius - Have pt shrug shoulders against resistance Sternocleidomastoid - Have pt turn face opposite side against resistance
75
What happens when you have a tumor develop in the Jugular Foramen?
CN IX, X, and XI will all be affected as they each travel through the Jugular Foramen
76
What is the function of CN XII?
CN XII (hypoglossal N.) has General Somatic Efferent Fibers - Motor to intrinsic tongue muscles, styloglossus, hypoglossus, and genioglossus
77
What is the tract of CN XII?
Emerges from the Medulla Exits skull via Hypoglossal canal travels with the cervical plexus Crosses the occipital artery Enters the oral cavity
78
How do you test CN XII?
Have patient protrude tongue If it deviates, something is wrog with CN XII
79
What nerves exit through the Cribriform Foramina?
CN I - Olfactory N.
80
What nerves exit through the optic canal?
CN II - Optic N.
81
What nerves exit through the Superior Orbital Fissure?
CN III - Oculomotor N. CN IV - Trochlear N. CN V1 - Opthalmic Branch of Trigeminal N. CN VI - Abducent N.
82
What nerves exit through the Foramen Rotundum?
CN V2 - Maxillary Branch of Trigeminal N.
83
What nerves exit through the Foramen Ovale?
CN V3 - Mandibular Branch of Trigeminal N.
84
What nerves exit through the Internal Acoustic Meatus?
CN VII - Facial N. | CN VIII - Vestibulocochlear N.
85
What nerves exit through the Jugular Foramen?
CN IX - Glossopharyngeal N. CN X - Vagus N. CN XI - Accessory N.
86
What nerves exit through the Hypoglossal Canal?
CN XII - Hypoglossal N.

Colin Neuro (15 decks)

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