Lecture 16- Clinical examination of eye movement

Question 1

aim of eye exam

Answer 1

Need to isolate an action of each muscle to test them

Question 2

basics of eye exam

Answer 2

• Ask pt to keep head still and follow finger
• In H shape

Question 3

• Some muscles share

Answer 3

movements of eye (when in resting position)

Question 4

action of lateral rectus

Answer 4

• Straight forward as performs one action on the eye
• Abduction- lateral

Question 5

action of medius rectus

Answer 5

Straight forward as performs one action on the eye

• adduction (medial)

Question 6

Elevation and depression (in midline) involves

Answer 6

two muscles

e.g. elevation (SR/ IO)

e.g. depress (SO/IR)

Question 7

outline action of superior rectus

Answer 7

elevate

adduct

intort

Question 8

outline action of inferior oblique

Answer 8

elevate

abduct

extort

Question 9

outline action of inferior rectus

Answer 9

depress

adduct

extort

Question 10

outline action of superior oblique

Answer 10

depress

abduct

intort

Question 11

• Muscles responsible for elevation and depression differ depending on

Answer 11

starting position of eye

Question 12

• Isolating elevation and depression action of SR/IO and IR/SO
  *

Answer 12

Cannot be isolated when testing from midline starting position

Question 13

how to isolate which muscle is affected

Answer 13

move starting posittion of eye

• If starting in an abducting (lateral) position (right eye)
  
  • Then ask to move eye up and down- rectus muscles more dominant action
  • Left eye will be testing the rectus muscles
• then test elevation and depression

Question 14

Recti muscles are main …….. (SR) and ………. (IR) of the eye when the eyeball is starting in the ………… positition

Answer 14

Recti muscles are main elevator (SR) and depressor (IR) of the eye when the eyeball is starting in the lateral position

Question 15

Oblique muscles are main …….. (IO) and ………. (SO) of the eye when the eyeball is starting in the ………… position

Answer 15

Oblique muscles are main elevator (IO) and depressor (SO) of the eye when the eyeball is starting in the medial position

Question 16

Ocular misalignment

Answer 16

strabismus

Question 17

strabismus is common in

Answer 17

children

Question 18

strabismus in children

Answer 18

• (congenital or develop in infancy)
  
  • Exact cause not known
  • Cover eye/ different lenses

Question 19

steabismus in adults

Answer 19

• acquired due to pathology or disease involving a number of different structures
  
  • NMJ- e.g. myasthenia gravis)
  • Nerve supplying the muscles (CNIII- oculomotor, IV trochlear, VI abducens)

Question 20

strabismus and how cranial nevres can be affected

Answer 20

• Vasculopathic (microvascular ischaemia- diabetes, hypertension)
• Physical compression e.g. tumour or aneurysm (III)
• Raised intracranial pressure

Question 21

CNIII - oculomotor innervates

Answer 21

• all extra ocular muscles (except LR and SO)
• muscles of the eyelid (LPS)
• sphincter pupillae muscle

Question 22

how ill a CNIII - oculomotor nerve lesion present

Answer 22

Down and out bitches

Question 23

Vasculopathic (microvascular) lesion of CNIII - oculomotornerve

Answer 23

e. g. caused by diabetes and hypertension
- down and out
- pupil will be spared

Question 24

compressive lesion (raised ICP, tumour, posteiror communicating artery aneurysm) on CNIII - oculomotor nerve

Answer 24

• down and out
• pupil involved (ma be involved first before other components involved)

Question 25

CN IV trochlear innervates

Answer 25

superior oblique muscle only

• intort
• depress
• abduct eye

Question 26

how will CN IV trochlear nerve lesion present

Answer 26

• EXTORTED
• slighly elevated
• adducted

Question 29

signs of trochlear nerve lesion

Answer 29

Head tilt- to compensate extortion

worsening diplopia (on downward gaze) especially looking down and medially e.g. walking down stairs or reading

• SO is main depressor of the eyeball when in adduction*
• SO weak- this action affected*

Question 30

CN VI abducens nerve innervates

Answer 30

lateral rectus

Question 31

CN VI abducens nerve lesion will present with

Answer 31

eye held in adduction–> horizontal diplopia

• unopposed pull of medial rectus muscle
• unable to abduct the eyes on affected side