Brain Stem and Cranial Nerves Exam

Question 1

before performing tonometry in clinic you instill a drop of topical anesthetic which of the following nerves are you likely to be blocking directly?

Answer 1

1. nasociliary nerve
2. short ciliary nerves

Question 2

which cranial nerves are located within the lateral wall of the cavernous sinus?

Answer 2

1. CN III
2. CN V maxillary division
3. CN IV
   *Think of OTOM acronym

Question 3

which nerves provide sensory innervation to the palpebral conjunctiva on the upper part of the eyelid?

Answer 3

1. supraorbital nerve
2. supratrochlear nerve

Question 4

when someone blinks forcefully what statements about this reflex are true?

Answer 4

1. the efferent signal is carried by CN VII
2. the afferent signal is carried by CN V

Question 5

A patient with Bell’s palsy is mostly like to have these ocular symptoms/signs ____?

Answer 5

• incomplete blink
• dry eye

Question 6

describe the trochlear nerve?

Answer 6

has the longest intracranial course of the nerves supplying the extraocular muscles

Question 7

What does the inferior division of the oculomotor nerve contain?

Answer 7

the parasympathetic motor fibers that innervate the iris and ciliary body

Question 8

which nerves enter the orbit through the superior orbital fissure within the annulus of Zinn?

Answer 8

inferior division of CNIII
superior division of CN III
optic nerve
nasociliary nerve
abducent nerve (VI)

Question 9

A patient presents with paralysis of the muscles on the lower left side of his face. the patient is able to raise his eyebrows on both sides of his face, what is the likely site of the lesion that could account for this?

Answer 9

motor cortex

Question 10

what is Herpes Zoster Ophthalmicus associated with?

Answer 10

may be associated with dendritic shaped corneal epithelial defects

Question 11

where is the trochlear nucleus located?

Answer 11

located rostral to the abducens nucleus

Question 12

A patient has had botox injections the upper part of their face to reduce forehead wrinkles. Which motor branch of the facial nerve is most likely to be impacted?

Answer 12

the temporal branch

Question 12

which brainstem nucleus is the target of afferent fibers that carry touch, pressure and vibration-sensitive fibers from the skin of the face?

Answer 12

pontine trigeminal nucleus

Question 13

A lesion in the abducens nucleus most likely cause which symptom?

Answer 13

horizontal gaze palsy

Question 14

describe the anatomy of the trigeminal ganglion?

Answer 14

it contains the cell bodies of sensory neurons that innervate the skin of the face and cornea

Question 15

a patient presents with reduced lacrimation and paralysis of the muscles of facial expression on the right hand side of the face, and reduced hearing in the right ear. What is the most likely site of a lesion that could cause these symptoms?

Answer 15

right internal auditory meatus

Question 16

describe the brainstem?

Answer 16

cranial nerves VI , VII and VIII emerge from the ventral aspect of the brainstem near the pontomedullary junction

Question 17

where does the abducens nerve exit?

Answer 17

exits the skull through the superior orbital fissure

Question 18

a lesion in which cranial nerve would result in ptosis?

Answer 18

oculomotor nerve CNIII

Question 19

A cluster of neuronal cell bodies in the CNS is called a ___?

Answer 19

nucleus

Question 20

the trochlear nucleus projects to the ___superior oblique muscle?

Answer 20

contralateral superior oblique muscle

Question 21

a sixth nerve palsy usually results in a compensatory head turn ___ the affected eye?

Answer 21

head TURN same/towards the affected eye

Question 22

the trigeminal motor nucleus is located _____ to the pontine trigeminal nucleus?

Answer 22

medial to the pontine trigeminal nucleus

Question 23

the geniculate ganglion is a parasympathetic ___ganglion?

Answer 23

sensory ganglion

Question 24

the external nasal nerve is a branch of the _______ ethmoidal nerve

Answer 24

anterior ethmoidal nerve

Question 25

the facial motor nucleus project to the _____ orbicularis oculi muscle?

Answer 25

ipsilateral orbicularis oculi muscle

Question 26

phenylephrine causes vascular ___?

Answer 26

constriction

Question 27

what is the cranial nerve number for the following?
- sensing a pinprick on the skin
- mastication (chewing)
- forcefully closing the lid

Answer 27

• sensing a pinprick on the skin = V2 of trigeminal nerve
• mastication (chewing) = V3 of trigeminal nerve
• forcefully closing the lid= VIII (7) facial

Question 28

what is the cranial nerve number for the following?
- puffing out the cheeks
-pupillary constriction
-taste sensation from the anterior 2/3 of the tongue

Answer 28

• puffing out the cheeks =VIII (7) facial

-pupillary constriction = III (3) oculomotor

-taste sensation from the anterior 2/3 of the tongue = VIII (7) facial

Question 29

what is the cranial nerve number for the following?
- raising and maintaining upper eyelid position
- hearing
-smiling
- increased lacrimation

Answer 29

• raising and maintaining upper eyelid position = III (3) oculomotor
• hearing = VIIII (8) vestibulocochlear

-smiling = VIII (7) facial

• increased lacrimation = VIII (7) facial

Question 30

explain why LASIK leads to dry eye symptoms? What are the afferent and efferent pathways involved?

Answer 30

• to make the corneal flap in LASIK the short ciliary nerves are cut normally the afferent pathway sensing the eye is dry would be short ciliary nerves & the efferent pathway is for lacrimation so cutting the short ciliary nerves would mean the eye cant tell its dry to produce more tears. The condition will improve as the nerves recover

Question 31

decussation is when__?

Answer 31

fibers cross from one side of a structure to the other

Question 32

sympathetic

Answer 32

initiates the bodies “fight or flight”response

Question 33

the dense packing of tracts and nuclei within the brain stem means even small lesions can___?

Answer 33

even small lesions can injure multiple tracks/ nuclei resulting in significant neurological deficits

Question 34

midbrain is CN____ and contains?

Answer 34

CN III (3) & IV (4) contains nerve tracts linking brainstem to thalami and cerebrum , superior and inferior colliculi

Question 35

Pons is CN___ and contains?

Answer 35

contains nuclei for
-sleep, respiration, swallowing, bladder control, eye movements (CN VI 6)

-facial sensation and expression (CNs V & VII 5 & 7)

• hearing and equilibrium (CN VIII 8)

Question 36

medulla contains nuclei for___?

Answer 36

respiration
heart rate
blood pressure
reflex centers (vomiting, sneezing, taste)

Question 37

what is the circle of willis?

Answer 37

interconnected arteries that permit collateral circulation in the event of obstruction of blood flow

Question 38

name the cranial nerves

Answer 38

1. olfactory
2. opic
3. oculomotor
4. trochlear
5. trigeminal
6. abducens
   7.facial
7. vestibulocochlear
8. glossopharyngeal
   10.vagus
9. accessory
10. hypoglossal

Question 39

some autonomic fibers hitch a ride with CN’s what are examples of this?

Answer 39

CN3 has both somatic motors to control EOM’s (voluntary movement= skeletal) & parasympathetic motor fibers to control pupils another example is branchial motor fibers associated with cranial nerve 5 and 7

Question 40

where is the somatic motor nuclei located?

Answer 40

midline & ventral

Question 41

where is the sensory nuclei located?

Answer 41

side & dorsal