Vision - Muscles and Neural Pathways

Question 1

What are the different types of ocular muscles?

Answer 1

Intrinsic

Extrinsic

Question 2

What is the role of the intrinsic muscles?

Answer 2

Control pupil diameter

Help alter lens curvature

Question 3

What is the role of the extrinsic muscles?

Answer 3

Move the eye

Question 4

How many extrinsic muscles are there?

Answer 4

6

Question 5

How many and what are the recti muscles?

Answer 5

4 recti muscles 
Medial rectus 
Lateral rectus 
Inferior rectus 
Superior rectus

Question 6

How many and what are the oblique muscles?

Answer 6

2
Superior oblique
Inferior oblique

Question 7

Where do the recti muscles arise from?

Answer 7

Apex of the orbit from an annular fibrous ring

Question 8

Where does the superior oblique arise from?

Answer 8

Roof of the orbit posteriorly

Question 9

Where does the inferior oblique arise from?

Answer 9

Floor of the orbit anteriorly

Question 10

What muscle elevates the upper eyelid?

Answer 10

Levator palpeerde superioris

Question 11

What nerve innervates the superior oblique?

Answer 11

Trochlear (4)

Question 12

What nerve innervates the lateral rectus?

Answer 12

Abducent (6)

Question 13

What nerve innervates the majority of extrinsic muscles?

Answer 13

Occulomotor (3)

Question 14

What axis are the extrinsic muscles attached along?

Answer 14

Orbital axis

Question 15

What does the medial rectus cause?

Answer 15

Adduction of eyeball

Question 16

What does the lateral rectus cause?

Answer 16

Abduction of eyeball

Question 17

What is the primary action of the superior rectus?

Answer 17

Elevation

Question 18

What is the primary action of the inferior rectus?

Answer 18

Depression

Question 19

What is the primary action of the superior oblique?

Answer 19

Intorsion

Question 20

What is the primary action of the inferior oblique?

Answer 20

Extorsion

Question 21

What is a strabismus?

Answer 21

Squint

Question 22

What is the cause of strabismus?

Answer 22

Misalignment of the eyes

Question 23

What is esotropia?

Answer 23

Convergent quint

Question 24

What is exotropia?

Answer 24

Divergent squint

Question 25

What are the consequences of a squint?

Answer 25

Amblyopia (lazy eye)

Diplopia (double vision)

Question 26

What are the intrinsic muscles of the eye?

Answer 26

Ciliaris muscle
Constrictor pupillae
Dilator pupillae

Question 27

What is the result of right optic nerve damage?

Answer 27

Blindness in one eye

Question 28

What is the result of optic chiasma disruption?

Answer 28

Bitemporal hemianopia

Question 29

What is the result of right optic tract damage?

Answer 29

Contralateral homonymous hemianopia

Question 30

What is the result of optic radiation damage

Answer 30

Contralateral homonymous hemianopia

Question 31

Through what pathway does light travel once it hits the retina?

Answer 31

Optic nerve, optic chiasma, optic tract

Question 32

What are the causes of pupil abnormalities?

Answer 32

Horner’s syndrome

Abnormal light reflex

Question 33

What is the pathway of the efferent limb?

Answer 33

Preganglionic parasympathetic past to the orbit
Parasympathetic fibres go to and synapse in ciliary ganglion
Postganglionic fibres go through short ciliary nerves o constrictor papillae

Question 34

What are the common causes of absent/abnormal pupillary reflex?

Answer 34

Detachement, degeneration or dystrophy of retina
Optic neuritis
Disease of the 3rd cranial nerve

Question 35

What are the clinical signs of Horner’s syndrome?

Answer 35

Ptosis
Anhidrosis
Anisocoria