Brainstem II: Eye movements and pupillary control

Question 1

Main actions of the Lateral Rectus on the eye?

Answer 1

Abduction

Question 2

Main actions of the Medial Rectus on the eye?

Answer 2

Adduction

Question 3

Main actions of the Superior Rectus on the eye?

Answer 3

Elevation and intorsion

Question 4

Main actions of the Inferior Rectus on the eye?

Answer 4

Depression and extorsion

Question 5

Main actions of the Inferior oblique on the eye?

Answer 5

Elevation and extorsion

Question 6

Main actions of the Superior oblique on the eye?

Answer 6

Depression and intorsion

Question 7

The superior division of CN III innervates?

Answer 7

Superior rectus, and levator palpebrae superioris.

Question 8

The inferior division of CN III supplies the?

Answer 8

Medial rectus, inferior rectus, and inferior oblique muscles.

Question 9

The oculomotor nuclei are located in the upper midbrain at the level of ?

Answer 9

The superior colliculi and the red nucleus.

Question 10

Trochlear nuclei are located in the lower midbrain at the level of the ?

Answer 10

Inferior colliculi and decussation of the superior cerebellar peduncle

Question 11

Nuclear and infranuclear pathways involve?

Answer 11

Brainstem nuclei of CN III, IV, and VI. The peripheral nerves arising from these nuclei; and the eye movement muscles.

Question 12

Supranuclear pathways involve?

Answer 12

The brainstem and forebrain circuits that control eye movements through connections with the nuclei of CN III, IV, and VI.

Question 13

Abnormal lateral deviation of one eye is called?

Answer 13

exotropia

Question 14

Abnormal medial deviation of one eye is called?

Answer 14

esotropia

Question 15

Vertical deviation of eyes in respect to the higher eye is called?

Answer 15

hypertropia.

Question 16

What connects the oculomotor, trochlear, abducens, and vestibular nuclei?

Answer 16

Medial longitudinal fasciculus

Question 17

During horizontal movement the ___________ nucleus functions as the horizontal gaze control center, controlling movements of both eyes?

Answer 17

Abducens nucleus of ipsilateral direction

Question 18

In the pontine regime tun near the abducens nucleus is an important horizontal gaze center called the?

Answer 18

Paramedian pontine reticular formation (PPRF)

Question 19

Classic neurological syndrome produced by an MLF lesion is called?

Answer 19

Internuclear ophthalmoplegia (INO)

Question 20

Common causes of INO are?

Answer 20

MS, Pontine infarcts, or neoplasms involving the MLF

Question 21

Lesions of the MLF and adjacent abducens nucleus or PPRF results in what?

Answer 21

one-and-a-half syndrome

Question 22

Important nucleus that is thought to help mediate downward gaze?

Answer 22

Rostral interstitial nucleus of the MLF

Question 23

Vergence movements are under the control of?

Answer 23

Descending inputs from the visual pathways in the occipital and parietal cortex

Question 24

Lesions compressing the dorsal midbrain and pretectal area can cause?

Answer 24

Parinaud’s syndrome

Question 25

4 components of Parinaud’s syndrome are?

Answer 25

1. Impairment of vertical gaze (especially upward)
2. Large irregular pupils
3. Eyelid abnormalities
4. Impaired convergence and sometimes convergence-retraction nystagmus (especially in attempted upgaze)

Question 26

Most common cause of Parinaud’s syndrome?

Answer 26

Pineal region tumors and hydrocephalus

Question 27

Most common (M/C) cause of CN III palsy?

Answer 27

aneurysm of the posterior communicating artery as it branches off of the internal carotid