Cranial Nerves Flashcards

1
Q
  • What type of CN is CN I (sensory or motor?)
A
  • Olfactory
  • Smell-sensory
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2
Q
  • What type of CN is CN II (sensory or motor)?
A
  • CN II=Optic Nere
  • Sensory-vision
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3
Q
  • What type of CN is CN III (sensory or motor)?
A
  • Oculomotor
  • Motor
    • Ciliary muscles
    • Sphincter pupillae
    • All extrinsic muscles of the eye (except those listed frmo CN IV and VI)
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4
Q
  • What type of CN is CN IV? (sensory or motor)
A
  • CN IV-Trochlear N
  • Motor-superior oblique m. of the eye
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5
Q
  • What type of CN is CN V (Sensory or motor)?
A
  • CN V=Trigeminal N. (Has both sensory and motor components)
  • Sensory root
    • Face, sinuses and teeth
  • Motor root
    • Muscles of mastication
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6
Q
  • What type of CN is CN VI (sensory or motor?)
A
  • CN VI=Abducent N.
  • Motor
    • Supplies lateral rectus muscles of the eye
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7
Q
  • What type of CN is CN VII (sensory or motor)?
A
  • CN VII=Facial N
  • Motor and sensory components
  • Motor
    • Muscles of facial expression (Primary root)
    • Submandibular, sublingual, and submaxillary glands (Intermediate n.)
  • Sensory
    • Taste to anterior 2/3 of tongue and soft palate (Intermediate n.)
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8
Q
  • What type of CN is CN VIII? (Sensory or motor)
A
  • CN VIII=Vestibulocochlear n.
  • Both portions are sensory
  • Vestibular n.
    • Sensory for orientation in space and motion
  • Cochlear n.
    • Hearing
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9
Q
  • What type of CN is CN IX? (Sensory or motor)
A
  • CN IX=Glossopharyngeal n.
  • Both sensory and motor components
  • Motor
    • Stylopharyngeus m
    • Parotid gland
  • Sensory
    • Taste-posterior 3rd of tongue
    • General sensation of
      • Pharynx
      • Tonsillar sinus
      • Pharyngotympanic tube
      • Middle ear cavity
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10
Q
  • What type of CN is CN X (sensory or motor)?
A
  • CN X=Vagus N
  • Has both sensory and motor components
  • Sensory
    • Pharynx
    • Larynx reflex sensation from tracheobronchial tree
    • Lungs
    • Heart
    • GI Tract to Left Colic Flexure
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11
Q
  • GSE
A
  • General somatic efferent
  • From brain to somatic muscle
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12
Q
  • GVE
A
  • General visceral efferent
  • Autonomics to SM, cardiac muscle and glands
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13
Q
  • SVE
A
  • Somatic visceral efferent
  • Muscles derived from the pharyngeal arches
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14
Q
  • GSA
A
  • General somatic afferent
  • Sensory in the skin, joint capsule, tendon, muscle
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15
Q
  • GVA
A
  • General visceral afferent
  • Sensory of visceral structures
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16
Q
  • SSA
A
  • Special somatic afferent
  • Hearing, balance and sight
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17
Q
  • SVA
A
  • Special visceral afferent
  • Taste and smell: Chemical senses
18
Q
  • CN I (Olfactory n.)
    • Function
    • Location
    • Tract
  • Clinical Notes
A
  • SVA (special sense of smell)
  • Located in olfactory organ
  • Cribiform plate to olfactory bulbs

Clinical N: Ansomnia (olfactory loss d/t damage of cribiform plate and CN I; function gradually decreases with age, but certain head traumas can lead to ansomnia)

19
Q
  • CN II (Optic N.)
    • Function
    • Location
    • Pathway
  • Clinical note: It is important to understand the close relationship between the optic chiasm and _
A
  • Function: Special sensory, sight (SVA)
  • Diencephalon (Develop as evaginations of diencephalon; CNS fiber tracts formed by axons of retinal ganglion cells, 3rd order neurons within cell bodies of the retina)
  • Exit orbit via optic canals-cross contralaterally at optic chiasm-optic tracts-thalamus-optic radiations-primary visual cortex

Pituitary Gland

20
Q
  • CNIII (Oculomotor n.)
  • Function
  • Tract
A
  • GSE-motor innervation to superior, medial and inferior recti and inferior oblique and levator palpebrae superioris
  • GVE-parasympathetic innervation to pupil and ciliary muscle
  • Tract:
    • Leaves midbrain
    • Pierces dura lateral to diaphragma sellae
    • Runs in lateral wall of cavernous sinus
    • Enters orbit via superior orbital fissure
21
Q
  • CN III Clinical Correlation
A
  • Oculomotor Palsy
  • Characteristic down and out position in affected eye
22
Q
  • CN IV (Trochlear n.)
  • Function
  • Tract
A
  • Function
    • GSE-motor innervation to superior oblique in eye
  • Tract
    • Exists dorsal surface of midbrain
    • Pierces dura mater at margin of tentorium cerebelli
    • Runs in lateral walls of cavernous sinus
    • Enters orbit via superior orbital fissure
23
Q
  • CN VI (Abducens N.)
  • Function
  • Tract
A
  • Function
    • GSE-innervation ot lateral rectus m.
    • Tract
      • Emerges from brainstem between pons and medulla
      • Traverses pontine cistern
      • Pierces dura covering clivus
      • Runs in cavernous sinus near ICA
      • Enters orbit via superior orbital fissure
24
Q
  • CN IV Palsy
A
  • Strabismusn (crossed eye) and diplopia (double vision)
    • Eye tilted boutward
    • Unable to look down/in
    • Head tilted away from affected side (to compensate)
25
Q
  • CN VI Palsy
A
  • Diplopia
  • Cant laterally move (look out) affected eye
26
Q
  • CN V (Trigeminal N)
    • Function
    • Tract
A
  • Function
    • SVE-motor innervation to muscles of mastication (PA1)
    • GSA-Sensory to the face and scalp
  • Tract
    • Emerges from lateral aspect of pons
    • Trigeminal ganglion located in trigeminal cave lateral to cavernous sinus
    • V1 Opthalmic: Passes thru cavernous sinus and enters orbit via superior orbital fissure
    • V2 Maxillary: Passes thru cavernous sinus and exits the skull via foramen rotundum
    • V3 Mandibular: Exits skull via foramen ovale
27
Q
  • Trigeminal N (CN V) Divisions
A
  • Opthalmic division
    • Sensation from cornea, skin of forehead and scalp, upper eye lid, part of nose and part of nasal cavity
  • Maxillary division
    • Sensation from skin of face, lower eyelid, cheek, upper lip, maxillary teeth, mucosa of nose, maxillary sinus
  • Mandibular division
    • Sensation from skin of mandible, lower lip side of head, mandibular teeth, TMJ joint, part of oral mucosa, anterior 2/3 of tongue, motor to muscle of mastication
28
Q
  • CN V: Clinical Correlates and Testing
A
29
Q
  • CN VII (Facial N.)
    • Function
    • Tract
A
  • Function
    • SVE-motor innervation to muscles of facial expression (PA2)
    • GVE-Parasympathetic innervation to lacrimal, nasal, and palatine glands, and submandibular and sublingual salivary glands
    • SVA-Taste to anterior 2/3 of tongue
    • GSA-Sensation to external acoustic meatus
  • Tract
    • Emerges from pontine-medullary junction
    • Traverses from posterior cranial fossa and exits the skull via the internal acoustic meatus
    • Runs in facial canal and exits via stylomastoid foramen
    • Passes through parotid gland
30
Q
  • What pneumonic can be used to remember the terminal branches of the facial nerve from superior to inferior
A
  • The Zebra Bit My Cheek
    • Temporal
    • Zygomatic
    • Buccal
    • Marginal mandibular
    • Cervical
  • or pA Tiny Zebra bit my cheek
    • Posterior auricular
    • Temporal
    • Zygomatic
    • Buccal
    • Marginal mandibular
    • Cervical
31
Q

Parasympathetics to the lacrimal gland

A
32
Q
  • Parasympathetics to the Salivary Glands
A
33
Q
  • Bells Palsy
A
  • Unilateral facial nerve paralysis
  • Idiopathic injury, mass, disease (HSV, Lyme)
  • Cannot blink, pucker lips, or keep food in mouth while chewing
  • Tx:
    • Steroid to reduce inflammation
    • Antiviral
    • Eye Drops (these patients also have dry eyes)
    • 80% recover if cause is idiopathic
34
Q
  • CN VIII (Vestibulocochlear n.)
    • Function
    • Tract
    • Clinical correlations
A
  • Function
    • SSA-special senses of hearing and equilibrium
  • Tract
    • Vestibular nerve-follows utricle and saccule
    • Cochlear n-follows cochlea
    • Enter skull via internal acoustic meatus and the brainstem at the pontine-medullary junction
  • Clinical Correlations
    • Tinnitus
    • Disturbance of balance
    • Nystagmus
    • Deafness
    • Acoustic neuroma
35
Q
  • CN IX (Glossopharyngeal N.)
    • Function
    • Tract
A
  • Function
    • GSA-sensation from ear and external auditory canal, posterior 1/3 of tongue
    • GVA-Sensory information from oropharynx and carotid body
    • SVA-Taste to posterior 1/3 of tongue
    • GVE-parasympathetics to parotid gland
    • SVE-Motor to stylopharyngeus m. (PA3)
  • Tract
    • Emerges from medulla and exits cranium via jugular foramen
    • Passes between superior and middle pharyngeal constrictors to enter oral cavity
36
Q
  • CN X (Vagus N.)
    • Function
    • Tract
A
  • Function
    • GSA- Sensation from external auditory canal and dura
    • GVA-sensory information from viscera, pharynx, larynx, aortic arch, epiglottis and base of tomngue
    • SVA-taste from epiglottis
    • GVE-Parasympathetics to viscera
    • SVE-Motor to constrictors of pharynx, palatine muscles, and intrinsic muscle of larynx (PA4,PA6)
  • Tract
    • Emerges from medulla and exits cranium thru jugular foramen
37
Q
  • CN XI (Spinal Accessory N.)
    • Function
    • Tract
    • Testing
    • Clinical Correlations
A
  • Function
    • GSE-Motor to sternocleidomastoid and trapezius muscles
  • Tract
    • Emerges from spinal cord and enters cranium thru foramen magnum
    • Exits skull thru jugular foramen
  • Testing is motor only
    • Trapezius-shrug shoulders against resistance
    • Sternocleidomastoid-turn face towards opposite side against resistance
  • Clinical Correlations:
    • Jugular foramen
38
Q
  • CN XII (Hypoglossal N.)
    • Function
    • Tract
    • Testing
    • Clinical Correlation
A
  • Function
    • GSE-motor to intrinsic tongue muscles and styloglossus, hypoglossus and genioglossus
  • Tract
    • Emerges from medulla and exits skull via hypoglossal canal
    • Travels with cervical plexus, crosses occipital artery and enters oral cavity
  • Testing
    • Protruded tongue deviates on ipsilateral side when lesioned
    • Or push tongue into cheek
39
Q

Summary of various brainstem nuclei and their components

A
40
Q

Summary of the cranial nerves and associated pathologies

A