474-475: Neuro Anatomy/Physio

Question 1

What is the cavernous sinus?

Answer 1

a collection of venous sinuses on either side of the pituitary

Question 2

What drains into the cavernous sinus?

Answer 2

blood from the eye and superficial cortex

Question 3

Where does the cavernous sinus drain to?

Answer 3

internal jugular vein

Question 4

Which cranial nerves pass through the cavernous sinus?

Answer 4

III, IV, V1, V2, and VI

Question 5

Which sympathetic nerves pass through the cavernous sinus?

Answer 5

postganglionic sympathetic fibers en route to the orbit

Question 6

Which artery passes through the cavernous sinus?

Answer 6

the cavernous portion of the internal carotid artery

Question 7

What deficits characterize the cavernous sinus syndrome? What is not affected?

Answer 7

ophthalmoplegia and decreased corneal and maxillary sensation; normal visual acuity

Question 8

What are three causes of cavernous sinus syndrome?

Answer 8

mass effect, fistula, thrombosis

Question 9

What artery lies between the optic chiasm inferiorly and the base of the brain superiorly?

Answer 9

ACA

Question 10

A patient presents with a jaw deviated toward the right on physical examination. You suspect a CN lesion. Which CN? What side is the lesion on?

Answer 10

Motor component of CN V on the right; jaw deviates toward side of lesion due to unopposed force from the opposite pterygoid muscle

Question 11

On CN exam you note the uvula deviates toward the right. Which CN is affected on which side?

Answer 11

CN X on the left; uvula deviates away from weakened left side

Question 12

On CN exam you note weakness when the patient turns her head to the left. Which CN is affected on which side? Which muscle?

Answer 12

CN XI on the right is affected –> SCM

Question 13

In a patient with weakness in turning her head to the right, what do you expect on examination of her shoulder elevation? Which nerve and muscle is affected in the shoulder?

Answer 13

CN XI lesion on the left –> left trapezius weakness –> drooping shoulder

Question 14

On CN exam your patient’s tongue deviates to the right. Which CN is affected on which side?

Answer 14

CN XII on the right (“lick your wounds”)

Question 15

What are the components of the outer ear?

Answer 15

Pinna, auditory canal, eardrum

Question 16

What is the middle ear? What is it’s main function?

Answer 16

An air-filled space with the ossicles (malleus, incus, stapes); amplifies sound

Question 17

What is the name of the structure in the cochlea that vibrates with sound waves? Describe its structural variation as it coils through the cochlea.

Answer 17

basilar membrane; thin and rigid at base of cochlea –> wide and flexible at apex near helicotrema

Question 18

What part of the basilar membrane vibrates in response to low frequency sound waves?

Answer 18

the apex

Question 19

What part of the basilar membrane vibrates in response to high frequency sound waves?

Answer 19

the base

Question 20

What are the Rinne and Weber test results in conductive hearing loss?

Answer 20

Rinne: bone > air (abnormal)
Weber: localizes to affected ear

Question 21

What are the Rinne and Weber test results in sensorineural hearing loss?

Answer 21

Rinne: air > bone (nml)
Weber: localizes to unaffected ear

Question 22

Why should you wear ear protection at a loud concert? What will be damaged, and what function will be lost first?

Answer 22

damage to stereocilliated cells in the organ of Corti –> loss of high-frequency hearing first

Question 23

What is the risk of a sudden extremely loud noise to your inner ear structures?

Answer 23

hearing loss due to tympanic membrane rupture

Question 24

A patient presents with paralysis of the face below the forehead on the right side. Where is the lesion?

Answer 24

UMN on the left (i.e. corticobulbar tract; or cortical lesion)

Question 25

A patient presents with paralysis of the left side of the upper and lower face. Where is the lesion?

Answer 25

LMN on the left (i.e. facial nerve proper)

Question 26

What are the components of the facial nucleus? Does complete destruction of the facial nucleus present like a UMN or LMN lesion, or components of both?

Answer 26

Upper division - receives input from both sides of cortex
Lower division receives input from contralateral cortex only
Presents as a LMN lesion

Question 27

What is the name given to idiopathic lesions of the facial nerve? What is the prognosis?

Answer 27

Bell’s palsy; gradual recovery in most cases

Question 28

What are 6 causes of facial nerve palsy?

Answer 28

1. Lyme dz
2. herpes simplex
3. herpes zoster
4. sarcoidosis
5. tumors
6. diabetes

Question 29

What is the treatment for facial nerve palsy?

Answer 29

Corticosteroids

Question 30

What 3 mm. close the jaw?

Answer 30

Masseter
teMporalis
Medial pterygoid
(M’s Munch)

Question 31

Which single muscle is responsible for jaw opening?

Answer 31

Lateral pteryoid (“Lateral Lowers”)

Question 32

What is the innervation to the muscles of mastication?

Answer 32

trigeminal nerve (V3)