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Flashcards in Eye Movement Deck (29):
0

Name the muscles of eye movement

Superior, inferior, lateral, medial rectus Superior oblique Inferior oblique

1

Action of the superior rectus? Innervation?

Elevates, rotates and adducts eyeball medially

(Inserts slightly medially to eye's vertical axis of rotation)

Oculomotor nerve

2

Action of the inferior rectus?

Innervation?

Depresses, adducts and rotates eyeball laterally

(Inserts slightly medially)

Oculomotor nerve

3

Action of the medial rectus?

Innervation?

Adducts eyeball

Oculomotor nerve

4

Action of the lateral rectus?

Innervation?

Abducts eyeball

Abducens nerve

5

Attachements and course of the superior oblique?

Originates from body of sphenoid bone. Tendon passes through trochlea, changes direction to go laterally, attaches to posterior surface of eye

6

What are the actions of the superior oblique?

Primary action: Intorsion (internal rotation)

Secondary action: Depression in adducted position (reading)

Tertiary action: Abduction

7

What does the superior oblique muscle do when acting alone?

Innervation?

Moves eye down and out

Trochlear

8

Attachments of the inferior oblique?

Originates from anterior part of the floor of the orbit and attaches deep to the lateral rectus, comes underneath the eye.

9

Actions of the inferior oblique?

Abducts, elevates and laterally rotates the eyeball

10

What is the equation for the innervation of the eye muscles?

LR6 SO4 R3

11

Innervation of the eye muscles?

Lateral rectus = CN VI - abducens nerve

Superior oblique = CN IV - trochlear nerve

All the rest = CN III - oculomotor nerve

12

What protects the cornea and eyeballs from injury, irritation and drying out?

Eyelids and lacrimal glands

13

Layers of the upper eyelid?

Skin

Areolar tissue

Fibres of orbicularis ori

Levator palpebrae superioris

Superior tarsus

Tarsal glands

Ciliary glands

Palpebral conjunctiva

14

What is the superior tarsus?

Dense connective tissue, a strengthening skeleton

Called the inferior tarsus on the lower lid

Superior tarsus muscle connects to it

15

What does the tarsal/Meibomian gland secrete?

Secrete oil - sebaceous

Prevent evaporation of the eye's tear film, preventing the eye from drying out

16

What are styes?

Blockage of the ciliary glands

17

What triggers reflex bilateral blinking?

Corneal drying

Corneal irritation/pain

Expectation of contact

Corneal blink/reflex (CN V and VII)

18

Which muscles open the eyelids?

Innervation?

Levator palpebrae superioris (oculomotor) and superior tarsal muscles (sympathetic)

19

Which muscle closes the eyelids? Innervation?

Orbicularis oculi

Facial nerve

20

What can happen if there is paralysis of the orbicularis oculi muscle?

Failure to close eyes eg Bell's palsy

Get loss of blink and corneal reflex

Dry eye, high chance of infection

21

What  can happen if there is paralysis of the levator palpebrae superioris?

(Oculomotor nerve)

Drooping of upper eyelid - ptosis

Vision is compromised

Have residual opening of the eye due to superior tarsal muscle (smooth muscle)

22

What happens if there is paralysis of the supeior tarsal muscle?

Partial ptosis

Vision usually ok

Eye opening ok due to LPS

Seen in Horner's syndrome with pupil constriction etc.

23

Function of lacrimal fluid?

Moistens and lubricates surface of conjunctiva

Provides some nutrients and oxygen

Contains lysozyme

24

Innervation of the lacrimal glands?

Parasympathetic fibres of the facial nerve

Sensory supply via lacrimal branch of the ophthalmic division of CNV which also goes to eyelid and conjunctiva

25

Where do tears produced by the lacrimal gland go?

Tears drain out of the punctum in the medial eyelids, flow down the lacrimal canal into the lacrimal sac. They then drain down the nasolacrimal duct into the inferior meatus of the nasal cavity.

26

What is seen when there is damage to the oculomotor nerve?

Superior eyelid droops (innervates LPS) and cannot be raised due to unopposed action of orbicularis oculi

Pupil is fully dilated and non-reactive (sphincter pupillae) due to unopposed action of dilator pupillae

Pupil is down and out - unopposed action of lateral rectus and superior oblique

27

Action of the ciliary muscle?

Innervation?

Changes the shape of the lens within the eye

Oculomotor nerve

28

Which nerve is damaged if the patient cannot abduct their eye and why?

Abducens nerve

Fully adducted by unopposed action of the medial rectus

Innervates the lateral rectus