cranial nerves

Question 1

CN’s emerging locations

Answer 1

I - cerebral hemispheres (telencephalon)
II - diencephalon
III, IV - midbrain
V - pons
VI-VIII - ponto-medullary junction
XI, X - medulla
SI - superior spinal cord
XII - medulla

Question 2

bones that make up the fossae

Answer 2

anterior - frontal, ethmoid, and sphenoid
middle - sphenoid and temporal
posterior - temporal and occipital, tiny bit of sphenoid

Question 3

CN I - VI pathways

Answer 3

I - fibers in cribiform plate of ethmoid
II - pass through optic canal
III - superior orbital fissure
IV - superior orbital fissure
V1- superior orbital fissure
V2 - foramen rotundum
V3 - foramen ovale
VI - superior orbital fissure

Question 4

EOMs

Answer 4

LR6 SO4 AO3
III - medial rectus, inferior rectus, inferior oblique, superior rectus, levator palpebrae superioris
IV - superior oblique (down adn out)
VI - lateral rectus (lateral gaze)

Question 5

CN VI palsy

Answer 5

no function of lateral rectus -> medial deviation when trying to look forward

Question 6

CN III palsy

Answer 6

only superior oblique and lateral rectus are working -> ptosis, depressed, and ABducted gaze

Question 7

cavernous sinus

Answer 7

CN III, IV, VI and ophthalmic and maxillary (V2) nerves pass through cavernous sinus
facial veins, superior and inferior ophthalmic veins drain posteriorly into cavernous sinus
veins pass closest to CN VI and can cause CN VI palsy

Question 8

CN V1

Answer 8

CN V1 - ophthalmic

sensory to superior face and scalp, globe, and nasal mucosa

Question 9

CN V2

Answer 9

CN V2 - maxillary

sensory to skin overlying maxilla, upper lip, maxillary teeth and sinuses, and palate

Question 10

CN V3

Answer 10

CN V3 - mandibular
sensory to skin over mandible, floor of mouth, mandibular teeth, and anterior tongue (lingual branch)
motor to muscles of mastication (temporalis, masseter, medial and lateral pterygoids)

Question 11

CN VII - XII pathways

Answer 11

VII - internal acoustic meatus and stylomastoid foramen
VIII - petrous portion of temporal bone, through internal acoustic meatus
IX - jugular foramen
X - jugular foramen
XI - jugular foramen and foramen magnum
XII - hypoglossal canal

Question 12

CN VII function

Answer 12

motor - muscles of facial expression

sensory - taste to ant 2/3 of tongue via chorda tympani (with lingual nerve)

Question 13

CN VII branches / paths

Answer 13

temporal
zygomatic
buccal
mandibular
cervical
(to zanzibar by motor car)
passes through parotid where it is called carotid plexus

Question 14

CN VIII

Answer 14

balance / equilibrium and hearing

Question 15

CN IX

Answer 15

motor - stylopharyngeus
sensory - mucosa of tympanic cavity and eustachian tube; carotid body and sinus (chemoreceptors, baroreceptors); posterior 1/3 of tongue (taste and somatic)

Question 16

CN X

Answer 16

motor - pharyngeal constrictors, laryngeal muscles
sensory (taste and somatic) to epiglottis
parasympathetics to thoracic and abdominal viscera up through transverse colon

Question 17

CN XI

Answer 17

motor to SCM and trapezius

Question 18

CN XII

Answer 18

tongue muscles except palatoglossus

Question 19

tongue

Answer 19

ant 2/3 taste - CN VII
ant 2/3 somatic - CN V3
post 2/3 taste and somatic - CN IX glossopharyngeal

Question 20

parasympathetic ganglia

Answer 20

ciliary
pterygopalatine
otic
submandibular

Question 21

injury to glossopharyngeal nerve

Answer 21

loss of taste to post 1/3 of tongue

Question 22

injury to vagus

Answer 22

soft palate deviation with deviation of uvula to the normal side
hoarseness

Question 23

injury to hypoglossal nerve

Answer 23

deviation of tongue toward affected side