Cranial Nerves Lecture 3

Question 1

Olfactory (CN I)

Answer 1

• Function: (SVA) special sense of smell
• Location: Olfactory organ
• Tract: Cribriform plate to olfactory bulbs

Question 2

Anosmia

Answer 2

Olfactory loss
• Contralateral nostril can compensate for
unilateral anosmia
• Causes: Head trauma, viral infections,
Intracranila lesions, nasal passage
obstruction

Question 3

Optic (CN II) function

Answer 3

(SSA) special sense of

vision

Question 4

Optic (CN II) tract

Answer 4

• Optic nerve fibers arise from ganglion
cells in retina
• Exit the orbit via the optic canal into the
middle cranial fossa
• Most fibers terminate in lateral
geniculate bodies of thalamus

Question 5

what is relationship of optic chiasm to pituitary?

Answer 5

right next to each other. Pituitary can compress and cause lateral vision loss in both fields (bitemporal hemainopia)

Question 6

what is relationship of internal carotid artery to optic chiasm

Answer 6

next to each other. aneurysm can compress optic chiasm

Question 7

CN II testing

Answer 7

• light and dark (head injury
• finger counting (head injury)
• snellens test (eye chart)
• visual field test (4 quadrants)
• peripheral vision
• pupillary light reflex
• blink reflex

Question 8

Oculomotor (CN III) function

Answer 8

• (GSE) Motor innervation to superior,
medial, and inferior recti and inferior
oblique and levator palpebrae
superioris
• (GVE) Parasympathetic innervation
to pupil and ciliary muscle

Question 9

Oculomotor (CN III) tract

Answer 9

• Leaves the midbrain
• Pierces dura lateral to
diaphragma sellae
• Runs in lateral wall of
cavernous sinus
• Enters orbit via superior
orbital fissure

Question 10

Trochlear (CN IV) function

Answer 10

Motor innervation to

superior oblique

Question 11

Trochlear (CN IV) tract

Answer 11

• Exits dorsal surface of
midbrain
• 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

Question 12

Abducens (CN VI) function

Answer 12

• (GSE) Motor innervation to the

lateral rectus

Question 13

Abducens (CN VI) tract

Answer 13

• Emerges from brainstem
between pons and medulla
• Traverses the pontine cistern
• Pierces dura covering the
clivus
• Runs in the cavernous sinus
near the ICA
• Enters orbit via superior
orbital fissure

Question 14

which 2 nerves can be compressed by aneurysm?

Answer 14

CN III and CN VI (between 2 arteries)

Question 15

Trigeminal (CN V) function

Answer 15

• (SVE) Motor innervation to muscles
of mastication (pharyngeal arch 1)
• (GSA) Sensory to the face and
scalp

Question 16

Trigeminal (CN V) tract

Answer 16

• Emerges from lateral aspect of pons
• Trigeminal ganglion located in the
trigeminal cave lateral to the
cavernous sinus

*branches to 3 different divisions

Question 17

• V1 Ophthalmic: tract

Answer 17

Passes through the
cavernous sinus and enters the orbit
via the superior orbital fissure

Question 18

v2 maxillary tract

Answer 18

Passes through the
cavernous sinus and exits the skull
via foramen rotundum

Question 19

v3 mandibular tract

Answer 19

Exits the skull via the

foramen ovale

Question 20

• Ophthalmic division: CN V

Answer 20

Sensation from cornea, skin of forehead and
scalp, upper eye lid, part of nose and part of
nasal cavity

Question 21

Maxillary division: CN V

Answer 21

Sensation from skin of face, lower eyelid,
cheek, upper lip, maxillary teeth, mucosa of
nose, maxillary sinus

Question 22

Mandibular division: CN V

Answer 22

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

Question 23

Facial (CN VII)

• Function:• (SVE)

Answer 23

• (SVE) Motor innervation to muscles of facial expression (pharyngeal arch 2)

Question 24

Facial (CN VII)

• Function:• (GVE)

Answer 24

• (GVE) Parasympathetic innervation to lacrimal, nasal, and palatine glands,
and submandibular and sublingual salivary glands

Question 25

Facial (CN VII) | • Function:•• (SVA)

Answer 25

• (SVA) Taste to anterior 2/3 of tongue

Question 26

Facial (CN VII) | • Function:•• (GSA)

Answer 26

• (GSA) Sensation to eternal acoustic meatus

Question 27

Facial Nerve tract

Answer 27

Tract: • Emerges from pontine-medullary junction • Traverses the posterior cranial fossa and exits the skull via the internal acoustic meatus • Runs in the facial canal and exits via the stylomastoid foramen • Passes through the parotid gland

Question 28

bells palsy

Answer 28

- problem with CN VII (facial) | - test= close eye and smile

Question 29

Vestibulocochlear (CN VIII) function

Answer 29

• (SSA) Special sense of hearing and equilibrium

Question 30

Vestibulocochlear (CN VIII) tract

Answer 30

• Vestibular nerve innervates the utricle and saccule, cochlear nerve innervates the cochlea. • Enter skull via the internal acoustic meatus • Enter brainstem on the pontine-medullary junction

Question 31

Glossopharyngeal (CN IX) function GSA

Answer 31

Sensation from ear and external auditory canal, and posterior 1/3 of tongue

Question 32

Glossopharyngeal (CN IX) tract

Answer 32

``` • Emerges from medulla • Exits cranium through jugular foramen • Passes between the superior and middle pharyngeal constrictors • Enters oral cavity ```

Question 33

Glossopharyngeal (CN IX) function GVA

Answer 33

Sensory information from oropharynx and carotid body

Question 34

Glossopharyngeal (CN IX) function SVA

Answer 34

(SVA) Taste to the posterior 1/3 of tongue

Question 35

Glossopharyngeal (CN IX) function GVE

Answer 35

Parasympathetics to parotid gland

Question 36

Glossopharyngeal (CN IX) function SVE

Answer 36

(SVE) Motor to stylopharyngeus muscles (pharyngeal arch 3)

Question 37

what 2 nerves are tested at same time?

Answer 37

glossopharyngeal and vagus (gag reflex)

Question 38

Glossopharyngeal Neuralgia

Answer 38

- eating and swallowing starts an intense pain | - idiopathic

Question 39

Vagus (CN X) GSA

Answer 39

Sensation from external auditory canal and dura

Question 40

Vagus (CN X) GVA

Answer 40

Sensory information from viscera, pharynx, larynx, | aortic arch, epiglottis, and base of tongue

Question 41

Vagus (CN X) SVA

Answer 41

Taste from epiglottis

Question 42

Vagus (CN X) GVE

Answer 42

Parasympathetics to viscera

Question 43

Vagus (CN X) SVE

Answer 43

Motor to constrictors of pharynx, palatine muscles, and | intrinsic muscle of larynx (pharyngeal arch 4 & 6)

Question 44

Vagus (CN X) tract

Answer 44

* Emerges from medulla | * Exits cranium through jugular foramen

Question 45

Spinal Accessory (CN XI) function

Answer 45

• (GSE) Motor to sternocleidomastoid and trapezius | *no sensory

Question 46

Spinal Accessory (CN XI) tract

Answer 46

``` • Tract: • Emerges from the spinal cord • Enters the cranium through foramen magnum • Exits the skull through the jugular foramen ```

Question 47

Hypoglossal (CN XII) GSE

Answer 47

Motor to intrinsic tongue muscles, and styloglossus, | hypoglossus and genioglossus.

Question 48

Hypoglossal (CN XII) tract

Answer 48

* Tract: * Emerges from the medulla * Exits skull via hypoglossal canal * Travels with the cervical plexus * Crosses the occipital artery * Enters the oral cavity