Head And Neck Session 5 Flashcards Preview

Semester 4 > Head And Neck Session 5 > Flashcards

Flashcards in Head And Neck Session 5 Deck (56):
1

What forms the superior border of the bony orbit?

Frontal and sphenoid

2

What forms the medial border of the bony orbit?

Ethmoid, maxillary, lacrimal and sphenoid

3

What forms the inferior border of the bony orbit?

Maxillary and zygomatic

4

What forms the lateral border of the bony orbit?

Zygomatic and sphenoid

5

What is found at the apex of the orbit?

Optic canal containing the optic nerve

6

What are the 4 important openings in the orbit?

Optic canal, superior and inferior orbital fissures and lacrimal fossa

7

Which aspects of the orbit are susceptible to Fx?

Medial and inferior

8

What is a blowout Fx of the orbit?

Orbital walls break allowing herniation of the orbital contents inferiorly into the maxillary sinus

9

Why might a pt with a blowout Fx have diplopia?

Inferior rectus muscle may have become tethered

10

How can a blowout Fx be identified on a radiograph?

Tear drop sign

11

Why is the blind spot on the optic disc?

There are no photoreceptors so light cannot be focused

12

Why do cataract sufferers wear sunglasses?

The lens becomes harder and flatter thus scattering light and causing glare

13

Which area of the eye gives the most accurate vision?

Fovea

14

Where is the fovea located?

In the centre of the macula

15

What is the function of the iris?

Can constrict and relax to alter aperture of pupil

16

Where is the iris found?

Between lens and cornea

17

What makes up the inner layer of the eye?

The posterior lateral neural layer and deeper pigmented layers of the retina

18

Which layer of the retina contains photoreceptors?

Posterior lateral neural layer

19

What forms the middle vascular layer of the eye?

Choroid, ciliary body and iris

20

What are the components of the choroid?

CT and BV

21

What forms the outer fibrous layer of the eye?

Sclera and cornea

22

What is the function of the sclera?

Attachment of the eye to extraocular muscles

23

What is the function of the cornea?

Light refraction

24

Which bones form the orbit?

Frontal, zygomatic, sphenoid, maxilla, lacrimal and ethmoid

25

Why can retinal detachment occur?

Retina is derived from ectoderm but choroid is derived from mesoderm

26

What causes the painless loss of sight seen in retinal detachment?

Loss of bloodflow to retina

27

Why is photophobia seen in meningitis?

Optic nerve and brain have same layers of tissue so infection spreads

28

What feature of the optic nerve allows infection to lead to meningitis?

Venous drainage allowing retrograde infection

29

What are the layers of tissue common to the optic nerve and brain?

Pia mater, arachnoid mata and dura mata

30

Why does the optic nerve have the same layers of tissue as the brain?

It is a brain fact not a proper nerve

31

What is the function of the posterior segment of the eye?

Keeps it spherical

32

What is the function of the anterior segment of the eye?

Supply nutrients to the lens

33

Where is the anterior chamber of the eye found?

Between cornea and iris

34

Where is the posterior chamber of the eye located?

Between the iris and ciliary processes

35

What does the anterior segment contain?

Aqueous humour

36

What produces aqueous fluid?

Ciliary body

37

How does aqueous fluid move to supply the avascular cornea and lens with oxygen and nutrients?

Moves through the iris

38

How does the aqueous fluid remove waste products from the cornea and lens?

Drains out through the trabecular meshwork into Schlamm's canal at the limbus then into 25-30 collector canals and finally into episcleral veins

39

What happens if the trabecular meshwork of the eye becomes blocked?

Drainage of aqueous humour impaired causing increase in volume in anterior chamber

40

Why does blockage of the trabecular meshwork of the eyes cause a painless loss of vision?

Increase in anterior chamber volume puts back pressure on vitreous body causing damage to the optic nerve

41

What is open-angle glaucoma?

Angle between cornea and iris increases due to accumulation of aqueous humour in the anterior chamber

42

Describe the passage of tears.

Formed in the lacrimal gland, moved inferiorly and medially across eye by opening and closing of the eyelids into lacrimal canal. Move into lacrimal sac, down nasolacrimal duct and into inferior meatus of nasal cavity

43

Where is the palpebral conjunctiva found?

On the inside of the eyelid

44

Where is the bulbar conjunctiva found?

Film covering the eye surface up to the limbus

45

In which conjunctiva can anaemia be identified?

Palpebral

46

What is he function of the eyelid?

To protect against injury, excessive light and dryness

47

In conjunctivitis, is the sclera implicated?

No, only the bulbar conjunctiva despite the red and inflamed appearance of the sclera

48

What is a myobium cyst?

Painless swelling of the tarsal gland

49

What is the treatment for a myobium cyst?

Hot compress

50

What is a stye?

Infection of the ciliary gland (usually staph aureus)

51

Why might Abx be given for a stye?

To prevent retrograde infection

52

What is the palpebral fissure?

Distance between the upper and lower eyelids

53

What would you look for O/E of the sclera?

Nodules, hyperaemia, discolouration

54

What would you look for O/E of the iris?

Colour, nodules, vascularity

55

How can the lacrimal apparatus be used to identify nasolacrimal blockage?

Gently press lacrimal sac on the inner orbital ring and material will move through punctuation in nasolacrimal obstruction

56

Where is the palpebral part of obicularis oculi found?

In the eyelid