Cranial Nerves: Motor

Question 1

What is CN III?

Answer 1

Oculomotor

Question 2

Where is the location of neuron cell bodies of CN III?

Answer 2

Upper Midbrain–oculomotor nucleus

Question 3

What is the passage of CN III through the skull?

Answer 3

Superior Orbital Fissure –Sphenoid bone

Question 4

Where does the oculomotor nerve emerge?

Answer 4

near median plane at junction of midbrain and pons–>cavernous sinus–> superior orbital fissure

Question 5

Where does the rectus m. originate?

Answer 5

common tendinous ring—oculomotor nerve ends up here

Question 6

Levator palpebrae innervated by:

Answer 6

Oculomotor III

Question 7

Superior Rectus m. innervated by:

Answer 7

Oculomotor III

Question 8

Inferior Rectus m innnervated by:

Answer 8

Oculomotor III

Question 9

Medial Rectus m. innervated by:

Answer 9

Oculomotor III

Question 10

Inferior Oblique m. innervated by:

Answer 10

Oculomotor III

Question 11

Oculomotor nerve palsy

Answer 11

causes ptosis = eyelid droop due to paralysis of levator palpebrae muscle

Question 12

Ptosis

Answer 12

paralysis of levator palpebrae~ eyelid droop

Question 13

What is the resting position of the eye?

Answer 13

Down and out when oculomotor isn’t working—when superior oblique and lateral rectus m. aren’t working

Question 14

CC: pupil is fixed and dialated

Answer 14

Oculomotor III is out

Question 15

A cavernous sinus injury causes damage to what cranial nerve?

Answer 15

CN III

Question 16

An aneurysm of posterior cerebral or superior cerebellar artery causes damage to which cranial nerve?

Answer 16

CN III

Question 17

CN IV

Answer 17

Trochlear

Question 18

Function of trochlear nerve?

Answer 18

somatic motor–eye movement

Question 19

Location of neuron cell body of Trochlear nerve

Answer 19

Lower midbrain: trochlear nucleus

Question 20

Where does trochlear nerve pass through skull

Answer 20

Superior Oribital fissure: sphenoid bone

Question 21

Where does the trochlear nerve emerge from midbrain?

Answer 21

from dorsal aspect of midbrain

Question 22

What is the only nerve to emerge dorsally from the skull?

Answer 22

Trochlear nerve

Question 23

What structure does the trochlear nerve innervate?

Answer 23

Superior oblique muscle

Question 24

What happens when the Trochlear nerve is injured?

Answer 24

Can’t look down when eye is adducted which is called diplopia

Question 25

What causes injury to trochlear nerve?

Answer 25

cavernous sinus injury

Question 26

What is CN VI

Answer 26

Abducent

Question 27

What is the fnx f CN VI?

Answer 27

somatic eye movement

Question 28

Location of NCB of Abducent?

Answer 28

Pons--abducent nucleus

Question 29

How does the Abducent nerve exit the skull?

Answer 29

sphenoid bone--superior orbital fissure

Question 30

What is the route of the Abducent nerve?

Answer 30

emerges near medial plane at jnx of pons and medulla--> through the cavernous sinus and superior orbital fissure--> through common tendinous ring

Question 31

What structure does the Abducent nerve innervate?

Answer 31

Lateral rectus muscles

Question 32

What causes horizontal diplopia (double vision)

Answer 32

Abducent nerve (VI)

Question 33

What causes impaired eye abduction?

Answer 33

Abducent nerve damage VI

Question 34

Which way does the eye turn when the Abducent nerve is damaged?

Answer 34

Eye turns medially~ medial rectus muscle out)

Question 35

What causes injury to Abducent nerve VI?

Answer 35

Cavernous sinus injury and fracture to base of skull

Question 36

What nerve is CN XI?

Answer 36

Accessory nerve

Question 37

Where is the location of neuronal cell bodies of CN XI?

Answer 37

Spinal Cord: anterior horn of cervicle region

Question 38

Where does the Accessory nerve pass through the skull?

Answer 38

Rootlets (intermediate in position of exit from sp cd) via foramen magnum --exits via jugular foramen

Question 39

What structures are innervated by the Accessory nerve?

Answer 39

SCM and and Trapezius

Question 40

What kind of injury would cause damage to accessory XI

Answer 40

neck laceration

Question 41

Special part of CN XI

Answer 41

spinal root represents CN XI in it's entirety, cranial roots emerge from medulla but those are part of CN X

Question 42

What nerve is CN XII?

Answer 42

Hypoglossal nerve

Question 43

The location of the NCB of CN XII?

Answer 43

Medulla--hypoglossal nucleus

Question 44

Where does the CN XII pass through the skull?

Answer 44

Occipital bone--hypoglossal canal

Question 45

What is the route of CN XII?

Answer 45

Emerges from sides of medulla anterior to olives--> passes through hypoglossal canal--> curves forward near angle of mandible superior to ansa cervicalis to enter tongue

Question 46

What structures does hypoglossal XII innervate?

Answer 46

All intrinsic tongue muscles | All extrinsic tongue muslces except Palatoglossus (CN X)

Question 47

What happens to tongue when there is a peripheral lesion in Hypoglossal CN XII?

Answer 47

tongue deviates towards side of injury | --lick your wounds

Question 48

What would cause an injury to hypoglossal CN XII

Answer 48

Neck laceration