Ocular: Orbital And Ocular Innervation I

Question 1

Superior division of the oculomotor nerve motor innervation:

Answer 1

-superior rectus
-lavatory palpabrae superioris

Question 2

Inferior division of oculomotor nerve motor innervation:

Answer 2

-medial rectus
-inferior rectus
-inferior oblique

Question 3

Trochlear nerve motor innervation:

Answer 3

Superior oblique

Question 4

Abducent nerve motor innervation:

Answer 4

-lateral rectus

Question 5

Facial nerve motor innervation:

Answer 5

-orbicularis oculi
-frontalis
-corrugator
-procerus

Question 6

Optic nerve sensory innervation:

Answer 6

-transmits visual information (sight)

Question 7

Ophthalmic nerve sensory innervation:

Answer 7

-globe
-superior eyelid
-medial regions of both eyelids

Question 8

Maxillary nerve sensory innervation:

Answer 8

-lower eyelid

Question 9

At the level of superior colliculus in the midbrain:

Answer 9

Oculomotor nucleus

Question 10

At the level of the inferior colliculus in the midbrain:

Answer 10

Trochlear nucleus

Question 11

Both oculomotor nucleus and Trochlear nucleus are located..

Answer 11

Ventral to cerebral aqueduct

Question 12

Pons contains the:

Answer 12

Abducens, facial, and vestibular nuclei

Question 13

Medial longitudinal fasciculus (MLF):

Answer 13

-myelinated tract enabling nerve fibers to cross over
-connects nuclei on each midline side

Question 14

Central caudal nucleus (CCN):

Answer 14

-single, centrally located
-controls both lavator palpebrae muscles

Question 15

Lesions at the brain stem are rare. True or false?

Answer 15

True

Question 16

Edinger-Westphal nuclei (EWN):

Answer 16

-parasympathetic
-on each side of midline of oculomotor nucleus complex
-controls ciliary muscle and pupillary sphincter

Question 17

Where does superior rectus sit in oculomotor nucleus complex?

Answer 17

Caudal/medial

Question 18

Where does medial rectus sit in oculomotor nucleus complex?

Answer 18

3 different locations centrally

Question 19

Where does inferior rectus sit in oculomotor nucleus complex?

Answer 19

Towards upper border

Question 20

Where does inferior oblique subnuclei sit in oculomotor nucleus complex?

Answer 20

Between other nuclei

Question 21

What fibers from oculomotor nucleus continue ipsilateral?

Answer 21

Inferior rectus, medial rectus, inferior oblique

Question 22

What fibers decussate and continue contralateral from oculomotor nucleus complex?

Answer 22

Superior rectus sub nuclei

Question 23

Both levator palpebrae muscles come from a ____________________in oculomotor nucleus complex

Answer 23

Single sub nucleus

Question 24

CN 3 palsy:

Answer 24

-nerve damage including ischemia and compression (aneurysm)
-parasympathetic fibers from EWN travel peripherally relative to oculomotor fibers
-microvascular supply is more rich towards the surface (more superficial)

Question 25

Ischemic etiology in CN 3 palsy are less likely to affect..

Answer 25

parasympathetic pupillary fibers

Question 26

Aneurysm in CN 3 palsy affects…

Answer 26

Both fibers, sympathetic and parasympathetic

Question 27

Main feature of CN 3 palsy in patients

Answer 27

One eye of pt goes down and out

Question 28

Clinical features of CN 3 palsy:

Answer 28

-ptosis -EOM deviation -compressive causes fixed dilated pupil -diplopia

Question 29

Trochlear nucleus is located at…

Answer 29

The midbrain at the level of inferior colliculus

Question 30

Trochlear nucleus is located:

Answer 30

-Anterior to cerebral aqueduct -dorsal to medial longitudinal fasiculus -inferior to oculomotor nucleus

Question 31

CN IV palsy:

Answer 31

-nerve damage including ischemia as well as compression -motor fibers only!

Question 32

CN 4 is the only cranial nerve that emerges from…

Answer 32

Dorsal aspect of the brainstem

Question 33

CN 4 supplies the ________________ side as it decussates

Answer 33

Contralateral

Question 34

CN 4 is responsible for what movements of the eye?

Answer 34

Intorsion, depression, and abduction

Question 35

Which nerve have the longest intracranial course?

Answer 35

Trochlear nerve

Question 36

Clinical features of CN 4 palsy:

Answer 36

-torticollis (abnormal head posture) -facial asymmetry -strabismus (hypertropia, excyclotorsion, esotropia) -diplopia

Question 37

Why does torticollis occur in CN 4 palsy

Answer 37

To compensate for the diplopia, pt may adopt head tilt and face turn to opposite side

Question 38

Abducens nuclei are located…

Answer 38

In the pons, lateral to the medial longitudinal fasciculus

Question 39

What nerve arcs around Abducens nerve?

Answer 39

Facial nerve (so damage here can affect both facial and Abducens nerve)

Question 40

CN 6 supplies the…

Answer 40

Ipsilateral lateral rectus

Question 41

CN 6 palsy

Answer 41

-inability to abduct the eye leading to horizontal diplopia and eye sitting inward -increased intracranial pressure

Question 42

Increased intracranial pressure can cause…

Answer 42

Downward herniation of the brainstem that can compress the nerve as it course over petrous ridge

Question 43

Cavernous sinus is located posterior to the…

Answer 43

Superior orbital fissure

Question 44

What courses through the cavernous sinus?

Answer 44

-CN 3, 4, and 6 -V1 and V2

Question 45

CN 2 travels superior to ____________________

Answer 45

Pituitary gland (above where nasal fibers decussate)

Question 46

How would CN 6 be the first nerve affected by an internal carotid artery aneurysm?

Answer 46

Located the closest to the internal carotid artery within the cavernous sinus

Question 47

Carotid-cavernous fistula (CCF)

Answer 47

-Abnormal connection between the carotid artery and/or its branches with the cavernous sinus -can be direct (high-flow) or spontaneous (indirect/low flow)

Question 48

Symptoms of CCF:

Answer 48

-chemosis -pulsatile proptosis -ocular bruit (blood flow sounds coming from eye)

Question 49

Cavernous sinus receives venous blood from the…

Answer 49

Brain, orbit, and pituitary gland