Eye anatomy

Question 1

Ask the patient to look in, then down

This tests what?

Answer 1

superior oblique

Question 2

Ask the patient to look out, then up

This tests what?

Answer 2

superior rectus

Question 3

A child has limited upward gaze in one eye after trauma. CT shows orbital floor fracture. What muscle is trapped?

Answer 3

Inferior rectus

Question 4

A trochlear nerve lesion (CN IV) would affect which eye movement?

Answer 4

Depression of the adducted eye (via superior oblique)

Question 5

A patient cannot abduct their eye on the left. Which cranial nerve is damaged?

Answer 5

Left abducens nerve (CN VI)

Question 6

A patient has vertical diplopia and difficulty walking down stairs. Which muscle is affected?

Answer 6

Superior oblique – CN IV (trochlear nerve)

Question 7

Which muscle is responsible for adducting the eye?

Answer 7

Medial rectus

Question 8

Lateral Rectus movements

Answer 8

1. Abduction
2. Moves eye outward

Question 9

Medial Rectus movements

Answer 9

1. Adduction
2. Moves eye inward

Question 10

Superior Rectus movements

Answer 10

1. Intorsion
2. Adduction
3. Moves eye up and in - elevation

Question 11

Inferior Rectus movements

Answer 11

1. Extorsion
2. Adduction
3. Moves eye down and in - depression

Question 12

Superior Oblique movements

Answer 12

Moves eye down and out
+ intorsion

Question 13

Inferior Oblique movements

Answer 13

Moves eye up and out
+ extorsion

Question 14

What does Intorsion mean?

Answer 14

Inward rotation of the top of the eyeball towards the nose

Question 15

What does extorsion mean?

Answer 15

Outward rotation of the top of the eyeball away from the nose

Question 16

What are the primary movements of the inferior oblique muscle?

Answer 16

Elevation and extorsion of the eye

Question 17

A child has limited upward gaze in one eye after trauma. CT shows orbital floor fracture. What muscle is trapped?

Answer 17

Inferior rectus

Question 18

What nerves mediate the corneal reflex (blinking when touched)?

Answer 18

1. CN V1 (afferent)
2. CN VII (efferent – orbicularis oculii)

Question 19

A labelled diagram of the retina shows a circular structure with no photoreceptors. What is this structure?

Answer 19

Optic disc (blind spot)

Question 20

Which bone forms the medial wall of the orbit and is most likely fractured in an orbital blowout fracture?

Answer 20

1. Maxilla (orbital floor)
2. ethmoid (medial wall)

Question 20

Name the 3 parts of the orbicularis oculi muscle

Answer 20

1. Palpebral part
2. Lacrimal part
3. Orbital part

Innervated by CN VII (facial nerve)

Question 21

Palpebral role

Answer 21

gently closes the eyelids

Question 22

Lacrimal role

Answer 22

involved in the drainage of tears

Question 23

Orbital role

Answer 23

tightly closes the eyelids

Question 24

A lesion in the right optic nerve would cause what to happen?

Answer 24

Right eye complete blindness

Question 25

A Lesion at the optic chiasm would cause what to happen?

Answer 25

Bitemporal hemianopia

Question 26

A lesion in the right optic tract would cause what to happen?

Answer 26

Left homonymous hemianopia = left field in both eyes lost

Question 27

A lesion in the Meyer's loop (temporal lobe) would cause what to happen?

Answer 27

Superior quadrantanopia

Question 28

They describe someone with a pituitary tumour and bitemporal field loss. What structure is compressed??

Answer 28

Optic chiasm

Question 29

Where is the optic chiasm in the brain?

Answer 29

Middle bit. Big X

Question 30

Eye-opening is caused by what?

Answer 30

Levator Palpebrae Superioris with Muller’s muscle (1) CN III (oculomotor nerve) = controls the voluntary lifting of the eyelid via LPS (2) Sympathetic fibres = control the involuntary tone of Müller's muscle to maintain eyelid elevation

Question 31

Eye closing is caused by what?

Answer 31

orbicularis oculi = Facial nerve (CN 7)

Question 32

Which muscle is primarily responsible for the voluntary closure of the eyelids?

Answer 32

Orbicularis oculi muscle

Question 32

Which cranial nerve is responsible for the motor control of the muscle that closes the eyelids?

Answer 32

Facial nerve