CN I, II, IV, VI, VIII, XI, XII

Question 1

Course of Optic CN

Answer 1

• Rods and cones to ganglion cells of retina–> Optic canal –> Optic Chiasm (Nasal (medial) fibers cross over to opposite side, tmporal (lateral) remain on same side)–> Optic tract –> Thalamus (lateral geniculate body)–> Occipital lobe (Visual cortex of cerbrum)

Question 2

Optic

Function

Origin

Path

Answer 2

Vision

Ganglion cells of retina

Optic canals of sphenoid

Question 3

Lesions of optic nerve

Answer 3

blindness

Question 4

Lesions of Optic Chiasm

Answer 4

Bitemporal hemianopsia

Knocks out nasal side

Question 5

Lesions on Optic Tract

Answer 5

Homonymous hemianopsia

Lose lateral on one side and nasal on opposite side

Question 6

Vestibulocochlear

Function

Answer 6

Vestibular branch: Balance and equilibrium

Cochlear branch: Hearing

Question 7

CN VIII

Arises from

Answer 7

Pntomedullary junction

Question 8

CN VIII

Path

Answer 8

Through Internal acoustic meatus of Temporal bone

Crosses posterior fossa

Question 9

CN VIII

Origin

Answer 9

Vestibular and cochlear ganglia

Question 10

CN VIII

Associated nuclei

Answer 10

Vestibular and cochlear nuclei

Question 11

Acoustic Neuroma

Answer 11

• Benign tumor of schwann cells
• Hearing loss and gait ataxia
• Can block CSF drainage of 4th ventricle leading to hydrocephaly
  
  • Vomitting, loss of conciousness, death

Question 12

CN IV

Function

Answer 12

Innervates superior oblique

Motor movement

Down and out

Depression and abduction

Question 13

CN IV

Origin

Answer 13

Troclear nucleus (Motor nucleus)

Question 14

CN IV

Arises from

Answer 14

Midbrain

In middle cranial fossa

Question 15

Trochlear Nerve Lesions

Answer 15

Diplopia- double vision

Eye is adducted and elevated

Question 16

CN VI

Arises from

Answer 16

Pontomedullary junction

Question 17

CN VI

Passes with

Answer 17

Passes forward with internal carotid artery through cavernous sinus

Question 18

CN VI

Function

Answer 18

Motor to lateral rectus (Abduction)

Question 19

CN VI

Origin

Answer 19

Abducen nucleus

Question 20

Cavernous Sinus

Answer 20

• Surrounds sella turcica
• Receives blood from superior and inferior opthalmic veins
• Drains into superior and inferior petrosal sinuses

Question 21

What structures are in the cavernous sinus

Answer 21

Internal carotid artery

CN III

CN IV

CN V1

CN V2

CN VI

Question 22

CN XI

Cranial root distribution

Answer 22

Anterior or medulla

Runs lateral in posterior fossa and joins spinal root

Question 23

CN XI

Spinal root distribution

Answer 23

ANterior grey horn of upper 5 segments of spinal cord

enters through foramen magnum

Question 24

CN XI

Cranial root function

Answer 24

Branchial motor, SVE

Motor for muscles of soft palate, pharynk and intrinsic of larynx (via vagus nerve, paryngeal plexus)

Question 25

CNXI

Cranial origin

Answer 25

Nucleus ambiguus

Question 26

CN XI

Spinal root function

Answer 26

GSE, somatic motor

Sternocleidomastoid and trapezius

Question 27

CN XI

Spinal root origin

Answer 27

Spinal accessory nucleus and spinal cord segments C1-C5

Question 28

CN XII

Arises and attaches

Answer 28

Arises from anterior of medulla

Enters root of tongue superior to hyoid bone and lateral to hyoglossus

Question 29

CN XII

Function

Answer 29

Motor to all intrinsic and extrinsic muscles of tongue except palatoglossus

Controls shape and movement

Question 30

CN XII

Origin

Answer 30

Hypoglossal nucleus

Question 31

CN XII
Lesions

Answer 31

Supranucllear lesions cause contralateral paralysis

Peripheral lesions cause ipsilateral paralysis, tongue deviates to injured side