1:2. Orbit and the Eye Anatomy Flashcards Preview

Ophthalmology > 1:2. Orbit and the Eye Anatomy > Flashcards

Flashcards in 1:2. Orbit and the Eye Anatomy Deck (67):
1

Name the bones (not the labels)

Beige = Frontal

Blue = Zygomatic

Purple = Maxilla

Red = Sphenoid

Yellow = Ethmoid

Dark Blue = Lacrimal

Green = Nasal

2

Name the labels (not the bones)

A --> F

A = Superior Orbital Fissue

B = Optic Canal 

C = Orbital Plate of the Frontal Bone 

D = Supraorbital Notch/Foramen

E = Orbital Plate of Ethmoid

F = Infraorbital Foramen

3

Name all the same labels on this skull?

Superior Orbital Fissure

Optic Canal

Orbital Plate of the Frontal Bone

Orbital Plate of the Ethmoid Bone

Supraorbital Notch

Infraorbital Foramen

4

Difference between a foramen and a notch?

Foramen is a complete circle

Notch is uncomplete - like a C shape

5

The bony orbit is described as a four sided pyramid

The apex is the orbital canal

What does the base make up?

What is it composed of?

The base makes up the orbital rim

Composed of superior, inferior, medial and lateral orbital margins

6

How is the eye protected from a direct blow?

Orbital Margins - superior orbital margin is further forward than inferior so eye is protected

 

Orbital rim - nothing bigger than the orbital rim will come into contact with the actual eye

 

7

Describe orbital blowout fractures?

The medial wall and orbit floor are very thin

In trauma, the orbital margins and rim don't fracture as they are strong

The medial wall and floor are very thin though and can break

Can cause an orbital blowout fracture

8

Complications of orbital blowout fracture?

Orbital contents can become trapped

Infraorbital neurovascular bundle can be damaged

9

If the infraorbital neurovascular bundle was damaged in a blowout fracture, what would happen?

Loss of sensation to face

10

The external eyelid is split into two parts:

Name them

Identify them

Orbital Part

Palpebral Part

X = Palpebral

Y = Orbital

11

Name the muscle that surronds the eye in the external layer?

Obicularis Oculi

12

What is the orbital septum?

This is a sheet of fascia below the eyelid

Found in the middle layer

This separates the superficial part of the eye from the deep part to prevent the spread of infection

13

Label these parts of the eyelid

Which layer is this?

 

A = Orbital Septum

B = Inferior Tarsus

C = Medial Palpebral Ligament

D = Superior Tarsus

E = Tendon of Levator Palpebrae Superioris

F = Lateral Palpebral Ligmanent

 

Internal Layer

14

What is the Tarsal gland?

Where is it found?

These secrete an oily/waxy substance that prevents the eyelids from sticking together and prevents tears from overflowing and streaming constantly

 

Found in the tarsal plates of the tarsi

15

Describe the Tarsi?

Found above and below the eye

Plates of fibrous connective tissue that give the eyelid its half moon shape

Give protection to eye and attachment for muscles

16

Where does the Levator Palpebrae superioris attach?

The superior Tarsi

17

Name the surface anatomy of the eye

A = Location of the lacrimal duct

B = Pupil

C = Blood Vessel (Conjuctival vessel)

D = Lacrimal Lake

E = Puncta

F = Lower eyelid, lined with Conjuctiva

G= Conjunctival Fornix

H = Sclera, covered by conjuctiva

I = Limbus/Corneoscleral Junction

18

What innervates the lacrimal gland?

CN VII (Facial Nerve) 

Parasympathetic

19

Describe how the lacrimal apparatus works?

CN VII Parasympathetic innervation

Lacrimal gland produces lacrimal fluid

Washes across eye

Collects in lacrimal lake

Drains out of Puncta

Drains into lacrimal sac

Drains along nasolacrimal duct

Eventually reaches inferior meatus

20

Where does the lacrimal fluid end?

Inferior Meatus

21

Coloured bit in the centre of the eye?

Black bit in the very centre of the eye?

White bit in the eye?

Clear, transparent bit that covers the coloured bit?

Iris

Pupil

Sclera

Cornea

 

22

What control is the pupil under?

Autonomic

23

Describe the layers of the eye?

Fibrous, Outer Part

Uvea = Middle Layer

Retina (Inner Layer)

24

Describe the outer layer of the eye

Tough and fibrous

Composed of two parts

Sclera - the white part where extra-ocular muscles attach. Makes up about 5/6ths of the eye

 

Cornea = Clear, colourless, front of the eye. Makes up most of the refractive power - the ability to focus light

25

Describe the middle layer of the eye

The Uvea

This is the vascular layer

Has three parts:

- Iris 

- Ciliary Body 

- Choroid

26

Describe the function of the three parts of the middle layer of the eye (the uvea)

Iris = Changes size of pupil

Ciliary Body = Attaches to iris. Changes shape of lens and secretes aqueous humour

Choroid = Provides nutrition and gas exchange 

27

Describe the inner layer of the eye?

This is photosensitive

Contains:

- Retina

- Macula

- Optic Disc

28

Describe the segments of the eye?

- Names?

- Where is the divide?

- Humour?

Dividied into anterior and posterior

LENS is the borders

Anterior = In front of Lens

Posterior = Behind lens

 

Anterior = Aqueous Humour

Posterior = Vitreous Humour

29

Describe the anterior segment of the eye?

Divided into two chambers - anterior and posterior

Anterior: Between cornea and iris

Posterior: Between iris and suspensory ligaments

Both contain aqueous humour

30

Describe the posterior segment of the eye?

This is everything found behind the lens (2/3rds of the eye)

Contains vitrous body which contains vitreous humour

Vitreous humour is gel like

Vitrous humour holds the lens and the choroid against the sclera

31

Describe floaters?

Commonly seen in the vitreous body

Caused by floating lumps of vitreous humour

32

Describe the circulation of aqueous humour?

1. Produced by ciliary body

2. Circulates within posterior chamber to nourish lens

3. Passes through pupil into anterior chamber

4. Nourishes cornea

5. Reabsorbed into the scleral venous sinus (Canal of Schlemm)

33

What is the posterior part of the retina called?

Fundus

 

34

Optic Disc:

- Site of what?

 

Macula

- Site of what?

 

Fovea

- Site of what?

Optic Nerve Formation (CN II)

Only point of entry/exit for blood vessels and nerves of CN II

Blind spot due to no photoreceptors

 

Macula

Site of greatest number of cones

 

Fovea

Depression in the macula

Site of most acute vision

35

If one branch of the retina is disrupted, what happens?

If the central artery/end vein is disrupted, what happens?

Only the area supplied by that branch affected will lose vision

If central artery is affected, all vision will by lost as entire retina is affected

36

Describe the layers of the retina?

1. Photoreceptors (MOST POSTERIOR)

2. Ganglion Cells (Anterior to photoreceptors)

3. Axons of the ganglion cells (Most anterior)

37

Describe the passage of light entering the eye (not including brain)

Comes through cornea

- Axons of ganglion

- Ganglion

- Photoreceptors

- Optic Nerve

38

Describe the visual pathway?

Light enters eyes

- Temporal or nasal retina

- Optic Nerve

- Optic Chiasma

- Optic Tract

- Optic Radiation

- Visual Cortex of the Occipital Lobe

39

Where is light from the right visual field processed?

Where is light from the left visual field processed?

Right --> Left

Left --> Right

40

Describe the visual pathway of light from the left visual field:

- Left Eye

- Right Eye

Left Eye:

Left Nasal Retina

Left Optic Nerve

Optic Chiasma

Right Optic Tract

Right Optic Radiation

Right side of the visual cortex

 

Right Eye: 

Right Temporal Retina

Right Optic Nerve

Optic Chiasma

Right Optic Tract

Right Optic Radiation

Right Visual Cortex

 

41

Describe the arterial blood supply to the orbit?

The Opthalmic artery is the first branch of the internal carotid

Gives off branches which supply the eye and oculomotor muscles

42

Describe the special relationship between light and superior/inferior

All light coming from superior hits the inferior part of the eye

All light coming from inferior hits the superior part of the eye

43

Describe where the internal carotid becomes the opthalmic?

The internal carotid passes through the carotid canal

Passes through the cavernous sinus

THEN the opthalmic artery comes off

44

Describe the branches of the opthalmic artery?

Nasal Cavity Branches (Supply Kiesselbach's area)

Forehead/Scalp Branches

Ciliary Branches (Supply the choroid and uvea - middle vascular layer)

Central Artery of the Retina

45

Describe the route of the central artery of the retina?

Branches from the opthalmic artery

Enters the optic nerve

Supplies retina

46

Describe what happens if the central artery of the retina is occluded?

The retina begins to die off as this is its only blood supply

47

What vein(s) drain the retina?

Central Vein only

48

Describe the venous drainage of the eye?

Retina = Central Vein

Everything else is mainly Superior Opthalmic Vein

- Forehead/Scalp vein

- Facial Vein

- Inferior Opthalmic vein 

ALL DRAIN INTO THE SUPERIOR OPTHALMIC VEIN

Drains into the cavernous sinus

49

Describe the danger triangle of the face?

From corners of mouth to nose

Squeezing spots in this area can pierce veins and lead to infections in bloodstream

Can lead to infections surronding the brain

50

Name the 7 extra-ocular muscles?

`Superior Rectus

Inferior Rectus

Medial Rectus

Lateral Rectus

Superior Oblique
Inferior Oblique

Levator Palpebrae Superioris

 

51

Describe where the 7 extra-ocular muscles insert?

First 6 (Rectus and Obliques) attach onto the sclera

The levator palpebrae superioris attachs onto the superior tarsus

52

 Name the parts of the eye (A--> I)

YELLOW IS MEANT TO BE F

A = Inferior Rectus

B = Lateral Rectus

C = Medial Rectus

D = Superior Rectus

E = Levator Palpebrae Superioris

F = Superior Oblique

G = Inferior Oblique

H = Superior Tarsus

I = Trochlea

53

What is the way to remember cranial nerve innervation of extra-ocular muscles?

LR6 SO4 AO3 

Lateral Rectus = 6 (Abducens)

Superior Oblique = 4 (Trochlear)

All others = 3 (Oculomotor)

54

Superior oblique is supplied by what?

Anatomically, how does this make sense?

Trochlear Nerve

Trochlea is the name of the small pulley that Superior Oblique passes through

55

What are the 6 movements on the eye?

Adduction

Abduction

Elevation

Depression

Intorsion

Extorsion

56

Do all the muscles have just one movement?

Eg: Superior Rectus

No, they have a primary movement and also secondary

Superior Rectus causes elevation of the eye

Also causes adduction and medial rotation (think the eye muscles attach medially)

57

How do you clinically test the lateral rectus?

Abduction of the eye

58

How do you clinically test the medial rectus?

Adduction of the eye

59

How do you clinically test the superior rectus?

Abduct the eye first

Elevate the eye

60

How do you clinically test the inferior rectus?

Abduct the eye

Depress the eye

61

How do you clinically test the superior oblique?

Adduct the eye

Depress the eye

62

How do you clinically test the inferior oblique?

Adduct the eye

Elevate the eye

63

Describe synergestic movement?

Give two exampels

When two or more muscles work together to perform a movement

Eg: Superior Rectus and Inferior Oblique work together to elevate the eye

 

Eg: Inferior rectus and superior oblique work together to depress the eye 

64

Describe antagonistic movement?

Give one example

This is when two or more muscles are competiting to try and move the eye in different directions:

Eg: Superior rectus tries to medially rotate the eye, inferior oblique tries to laterally rotate the eye

65

Describe pure elevation and pure depression

Elevation:

Superior rectus and inferior oblique both try to move the eye upward (syngerstically) They both try to rotate in different directions (anatagonistically). This cancels each other out and results in pure elevation

 

Depression:

Inferior rectus and superior oblique both try to move the eye downwards (syngerstically). Both try to adduct/abduct the eye differently (antagonists). Cancels each other out and results in pure depression

66

https://www.bmc.med.utoronto.ca/anatomia/intro.swf

 

Go onto this website and view their anatomy dissection

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67

https://cim.ucdmc.ucdavis.edu/eyes/version1/eyesim.htm

 

Use this interactive eye simulator and quiz

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