The eye muscles

Question 1

What do dextro and levo mean?

Answer 1

dextro = right and levo= left

Question 2

Intorsion and extorsion?

Answer 2

tilt head to one side and eye will go towards the nose and one away

Question 3

Are the EOM’s attached along the orbital or optical axis?

Answer 3

orbital

Question 4

What is the relation of the orbital axis to the optical axis?

Answer 4

at angles to eachother

Question 5

What is the affect of the muscles being attached along the orbital axis?

Answer 5

pull eye at an angle and hence have more than one movement/action of the eye

Question 6

Are the obliques attached to the anterior or posterior part of the sclera?

Answer 6

posterior

Question 7

Does the anterior part of the eye move in the same or opposite direction of that the oblique has pulled it?

Answer 7

opposite

Question 8

What 3 EOM’s have only 1 action on the eyeball?

Answer 8

the medial and lateral recti

Question 9

What do the lateral and medial recti do to the eyeball?

Answer 9

medial - adducts lateral - abducts

Question 10

superior rectus actions

Answer 10

elevation - LR

intorsion - MR

Question 11

inferior rectus actions

Answer 11

depression - LR

extorsion - MR

Question 12

superior oblique action

Answer 12

intorsion - LR

depression - MR

Question 13

inferior oblique action

Answer 13

extorsion - LR

elevation - MR

Question 14

obliques elevate/depress when eye is…

recti elevate/depress when eye is…

Answer 14

adducted

abducted

Question 15

strabismus

Answer 15

misalignment of the eyes - squint

Question 16

Esotropia

Answer 16

manifest convergent squint

Question 17

Exotropia

Answer 17

manifest divergent squint

Question 18

2 functional consequences of squint

Answer 18

amblyopia - lazy eye

diplopia - double vision

Question 19

Amblyopia/lazy eye - how does it work?

Answer 19

brain suppresses image of one eye leading to poor vision with no pathology

Question 20

What type of squints are diplopia usually seen with?

Answer 20

nerve palsy

Question 21

pupillary reaction to increased illumination

Answer 21

parasympathetic - pupils constrict

Question 22

pupillary reaction to decreased illumination

Answer 22

sympathetic - pupils dilate

Question 23

How would you test pupillary reflex? (brief)

Answer 23

use a pen torch in a dimly lit room on one eye which should constrict both eyes
move torch to other eye - both sides should still be constricted

Question 24

Afferent pathway for light reflex

Answer 24

optic nerve -> optic chiasma -> optic tract -> midbrain ( CN 3 nucleus) -> EWN for parasympathetic -> nerve fibres for pupillary reflex -> midbrain

Question 25

Do pupillary reflex fibres go to LGB?

Answer 25

NO - EWN

Question 26

efferent pathway for light reflex

Answer 26

EWN -> preganglionic parasympathetic fibres synapse in ciliary ganglion and send short ciliary fibres to constrictor pupillae –> pupillary constriction on both sides

Question 27

Aniscoria

Answer 27

pupils of different sizes

Question 28

What is a condition that aniscoria may be found?

Answer 28

Horner’s syndrome

Question 29

3 reasons for pupils looking normal but reacting abnormally to light?

Answer 29

retinal diseases
optic nerve disease
CN 3 disease

Question 30

retinal disease examples

Answer 30

detachment, dystrophy, degeneration

Question 31

optic nerve neuritis disease example

Answer 31

MS

Question 32

If there is an absent parasympathetic pupillary reflex to light what can this mean?

Answer 32

cerebral artery aneurysm

diabetes would have no damage to parasympathetic fibres

Question 33

Horners aniscoria - damage to sympathetic or parasympathetic fibres?

Answer 33

sympathetic - dilation

Question 34

3 signs of horner’s anisocoria

Answer 34

miosis - constricted pupil
anhidrosis - sweating on affected side
ptosis - drooping of eyelid

Question 35

What region of the vertebra is sympathetic outflow?

Answer 35

thoraco-lumbar

Question 36

In the head and neck how to postganglionic sympathetic fibres travel?

Answer 36

along with blood vessels