Cranial Nerves III, IV, VI (3,4,6)

Question 1

Occulomotor nerve (3rd) Motor for most of

Answer 1

extraocular muscles.

Question 2

Occulomotor nerve (3rd) carries parasympathetic fibers to the

Answer 2

pupillary constrictor and ciliary muscles.

Question 3

Occulomotor nerve (3rd) nucleus

Answer 3

Main occulomotor nucleus
Accessory nucleus (Edinger Westphal nucleus)

Question 4

Which occulomotor nucleus Lies in the mid brain, at the level of superior colliculus

Answer 4

Main occulomotor nucleus

Question 5

Which occulomotor nucleus Lies dorsal to the main motor nucleus

Answer 5

Accessory nucleus (Edinger Westphal nucleus)

Question 6

Occulomotor nerve cells are parasympthatic neurons for

Answer 6

Accommodation reflex
Direct & consensual reflexes

Question 7

Occulomotor nerve _____ curve ventrally through the red nucleus in the midbrain

Answer 7

from the oculomotor nucleus

Question 8

Occulomotor nerve In the middle cranial fossa it divides into superior and inferior divisions which pass to the orbit through the

Answer 8

superior orbital fissure

Question 9

The parasympathetic fibers accompany oculomotor nerve fibers to the orbit, where they terminate in _______ then fibers pass to ___

Answer 9

ciliary ganglion
short ciliary nerves

Question 10

parasympathetic fibers terminate in ciliary ganglion,then fibers pass through the short ciliary nerves to eyeball, where they supply:

Answer 10

Constrictor pupillae muscle of the iris
Ciliary muscles

Question 11

Occulomotor nerve supplies (motor) :

Answer 11

Levator palpebrae superioris
Superior rectus muscle
Medial rectus muscle
Inferior rectus muscle
Inferior oblique muscle

Question 12

Occulomotor nerve supplies parasympathetic fibers :

Answer 12

Constrictor pupillae
Ciliary muscles.

Question 13

Occulomotor nerve responsible for

Answer 13

• Elevation of upper eyelid (open the eye)
• Turning the eyeball upward, downwards and medially
• Constriction of the pupil
• Accommodating reflex of the eyes

Question 14

Occulomotor nerve lesions results in

Answer 14

• Lateral squint
• Ptosis
• Diplopia
• Pupillary dilatation
• Loss of accommodation
  -The eyeball is fully abducted and depressed (down and out)

Question 15

The nerve that emerges immediately caudal to the inferior colliculus, on the dorsal surface of brain stem is called

Answer 15

Trochlear nerve (4th)

Question 16

Trochlear nerve (4th) passes forward in the

Answer 16

lateral wall of the cavernous sinus

Question 17

Trochlear nerve (4th) passes forward in
the lateral wall of the cavernous sinus then enters the orbit through

Answer 17

superior orbital fissure

Question 18

Trochlear nerve (4th) supplies

Answer 18

Superior oblique muscle

Question 19

Trochlear nerve (4th) function

Answer 19

Rotates the eye ball downwards and laterally

Question 20

Trochlear nerve (4th) lesions

Answer 20

• Diplopia
• Inability to rotate the eyeball infero-laterally
• eye deviates upward and slightly inward
• difficulty in walking downstairs

Question 21

Abducent nerve (6th) has how many motor nucleuses ?

Answer 21

One

Question 22

Abducent nerve (6th) Lies in

Answer 22

caudal pons in the floor of the 4th ventricle

Question 23

Abducent nerve (6th) emerges from

Answer 23

ventral aspect, at the junction of the pons and the medulla oblongata

Question 24

Abducent nerve (6th) passes through

Answer 24

Cavernous sinus

Question 25

Abducent nerve (6th) enters orbit through

Answer 25

Superior orbital fissure

Question 26

Abducent nerve (6th) supplies

Answer 26

lateral rectus muscle (rotates the eye ball laterally (abduction))

Question 27

Abducent nerve (6th) lesions

Answer 27

- Inability to direct the affected eye laterally (result in medial squint) -A nuclear lesion may involve nearby nucleus/axons of the facial nerve, causing paralysis of all facial muscles in ipsilateral side.

Question 28

Optic nerve type

Answer 28

Special sensory nerve

Question 29

Optic nerve lesion

Answer 29

- visual field defects - loss of vision - Anopsia

Question 30

Visual pathway

Answer 30

1. Optic nerve 2. Optic chiasm 3. Optic tract 4. Lateral geniculate body (nucleus) 5. Optic radiation 6. Visual cortex

Question 31

Three neurons pathway: 1st order neurons:

Answer 31

Bipolar cells of retina

Question 32

Three neurons pathway: 2nd order neurons:

Answer 32

Ganglion cells of retina (Their axons form the optic nerve)

Question 33

Three neurons pathway: 2nd order neurons:

Answer 33

Neurons in the lateral geniculate body (Their axons terminate in primary visual cortex)

Question 34

Axons of retinal ganglion cells converge at the

Answer 34

optic disc and pass as the optic nerve

Question 35

Optic nerve exits through the _____ to enter ____ to form the ___

Answer 35

Optic canal Middle cranial fossa Optic chiasma

Question 36

Fibers from the nasal medial half of retina cross in the ___ and join uncrossed fibers from the ______ to form the _______

Answer 36

Chiasma temporal lateral half of the retina optic tract

Question 37

The decussation (cross) of nerve fibers in the chiasm results in the

Answer 37

right optic tract conveying impulses from the left visual field and vice versa

Question 38

The partial crossing of optic nerve fibers in the optic chiasma is a requirement for

Answer 38

Binocular vision

Question 39

Fibers in the optic tracts Mainly terminate in the

Answer 39

lateral geniculate body (LGB) of the thalamus (3rd order neuron)

Question 40

A few optic fibers terminate in

Answer 40

pretectal area and superior colliculus (related to light reflexes)

Question 41

From the lateral geniculate nucleus (third-order neuron), the fibers project as the ____ which terminates in the _____ which terminates in ____

Answer 41

optic radiation primary visual cortex of the occipital lobe

Question 42

The primary visual cortex is located

Answer 42

medial surface of the hemisphere (region above and below calcarine sulcus)

Question 43

Visual field defects

Answer 43

Disease of the eyeball Disease of the optic nerve Compression of the optic chiasm

Question 44

Vascular and neoplastic lesions of the optic tract, optic radiation or occipital cortex produce :

Answer 44

contralateral homonymous hemianopia

Question 45

disease of the optic nerve (multiple sclerosis and optic nerve tumors) leads to

Answer 45

Vision loss in affected eye

Question 46

Compression of the optic chiasm by an adjacent pituitary tumour leads to :

Answer 46

bitemporal hemianopia