Basic Ophthalmology Anatomy Flashcards Preview

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Flashcards in Basic Ophthalmology Anatomy Deck (39)
1

what are the 7 bones of the orbit?

frontal
zygomatic
maxilla
lacrimal
ethmoid
sphenoid
palatine bones

2

what are the important entrance/exit points in the bony anatomy of the orbit?

supraorbital foramen/notch
infraorbital foramen
superior orbital fissure
inferior orbital fissure
optic canal

3

what passes through the supraorbital foramen/notch?

supraorbital nerve and vessels

4

what passes through the infraorbital foramen?

infraorbital nerve and vessels

5

what passes through the superior orbital fissure?

CN III
CN IV (trochlear - superior oblique)
CN V1
CN 6 (abducens - lateral rectus)

6

what passes through the optic canal?

CN 2

7

where is the optic canal found?

on posterior wall
medial to superior orbital fissure

8

what is the area where the iris meets the sclera called?

corneal limbus

9

how many lacrimal puncta are there and where do they lead to?

2
- one on upper lid - drains into superior lacrimal canal > nasolacrimal duct
- one on lower lid - drains into inferior lacrimal puncta > nasolacrimal duct

10

where is the lacrimal gland found?

superior and lateral to the eye (brow bone)

11

what are the 2 types of conjunctiva?

tarsal conjunctiva = lines inner surface of eyelid
bulbar conjunctiva = lines sclera up until the corneal limbus

12

what are the 2 cavities of the eye and what do they consist of?

anterior cavity
- anterior chamber = between cornea and iris
- posterior chamber = between iris and lens
posterior cavity
- contains vitreous chamber

13

what are the 3 groups of extraocular muscles?

rectus muscles
oblique muscles
levator palpebrae superioris

14

what are the 3 intraocular muscles?

ciliary muscles
sphincter pupillae
dilator pupillae

15

where is the trochlea found?

superior nasal aspect of the frontal bone within the orbit

16

on which side of the eye does the inferior rectus attach?

lateral

17

2 main actions of the superior oblique?
how can this be tested?

moves eye ball down and in which leads to looking down and out
intorsion when looking straight ahead
tested by making patient look down and in

18

3 main actions of inferior oblique?

extorsion
elevation
abduction

19

how is the action of inferior oblique tested?

make patient look up and in

20

why does testing of the oblique muscles not match their function?

as their elevation/depression functions are strongest on adduction

21

the ciliary muscles are part of what?

part of ciliary body

22

what do the ciliary muscles do?

act as part of accommodation reflex
contraction causes relaxation of suspensory ligaments and allows lens to thicken allowing focus to shift to close up objects

23

what do the sphincter pupillae muscles do?

also activate in accommodation reflex as well as the light reflex to constrict the pupil

24

what do the dilator pupillae muscles do?

increase diameter of the pupil

25

are the intraocular muscles under sympathetic or parasympathetic control?

ciliary and sphincter pupillae muscles = parasympathetic
dilator pupillae = sympathetic

26

what nerve is responsible for special sensory (vision) in the eye?

CN 2 (optic)

27

sensory innervation of the eye?

CN V1

28

motor innervation of the eye?

CN III
CN IV (trochlear = superior rectus)
CN VI (abducens = lateral rectus)

29

how is the autonomic nervous system involved in the eye?

sympathetic fibres from internal carotid plexus
parasympathetic fibres from edinger westphal nucleus, carried in CN III to ciliary ganglion

30

sign of CN III palsy?

eye fixed in down and out position
dilated (blown) pupil

31

sensory control of the cornea?

CN V1

32

how does CN II provide special sensation of vision?

both optic nerves converge at the optic chiasm where information is exchanged, dividing visual information into right and left visual field, rather than right and left eye
nasal retinal fibres (temporal visual field) cross over to the contralateral side of the brain and join temporal retinal fibres (nasal visual field) which do not cross
these mixed fibres form the optic tract

33

how do the optic tracts travel to the primary visual cortex?

information on the left and right visual fields continue to the lateral geniculate nucleus of the thalamus
from here information is split again into superior and inferior visual fields
- superior visual fields reach the primary visual cortex via the temporal lobe (Meyers loop)
- inferior visual fields will reach the primary visual cortex via the parietal lobe

34

what are the 3 parts of the accommodation reflex?

convergence
thickening of lens
pupillary constriction

35

what nerves mediate the pupillary light reflex?

afferent pathway = CN II (optic)
efferent pathway = CN III (oculomotor)

36

2 divisions of pupillary light reflex?

direct
consensual

37

what is the corneal reflex?

eyes should close in response to a physical stimuli stimuli applied to the cornea

38

what nerves mediate the corneal reflex?

afferent pathway = CN V1
efferent pathway = CN VII

39

describe blood supply to the eye

ophthalmic artery branches off internal carotid (1st branch)
ophthalmic artery branches to:
- central retinal artery = enters via optic nerve and supplies inner retinal layers
- posterior ciliary artery = enters eye outside of optic nerve and supplies middle and outer retinal layers