Head And Neck Session 5

Question 1

What forms the superior border of the bony orbit?

Answer 1

Frontal and sphenoid

Question 2

What forms the medial border of the bony orbit?

Answer 2

Ethmoid, maxillary, lacrimal and sphenoid

Question 3

What forms the inferior border of the bony orbit?

Answer 3

Maxillary and zygomatic

Question 4

What forms the lateral border of the bony orbit?

Answer 4

Zygomatic and sphenoid

Question 5

What is found at the apex of the orbit?

Answer 5

Optic canal containing the optic nerve

Question 6

What are the 4 important openings in the orbit?

Answer 6

Optic canal, superior and inferior orbital fissures and lacrimal fossa

Question 7

Which aspects of the orbit are susceptible to Fx?

Answer 7

Medial and inferior

Question 8

What is a blowout Fx of the orbit?

Answer 8

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

Question 9

Why might a pt with a blowout Fx have diplopia?

Answer 9

Inferior rectus muscle may have become tethered

Question 10

How can a blowout Fx be identified on a radiograph?

Answer 10

Tear drop sign

Question 11

Why is the blind spot on the optic disc?

Answer 11

There are no photoreceptors so light cannot be focused

Question 12

Why do cataract sufferers wear sunglasses?

Answer 12

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

Question 13

Which area of the eye gives the most accurate vision?

Answer 13

Fovea

Question 14

Where is the fovea located?

Answer 14

In the centre of the macula

Question 15

What is the function of the iris?

Answer 15

Can constrict and relax to alter aperture of pupil

Question 16

Where is the iris found?

Answer 16

Between lens and cornea

Question 17

What makes up the inner layer of the eye?

Answer 17

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

Question 18

Which layer of the retina contains photoreceptors?

Answer 18

Posterior lateral neural layer

Question 19

What forms the middle vascular layer of the eye?

Answer 19

Choroid, ciliary body and iris

Question 20

What are the components of the choroid?

Answer 20

CT and BV

Question 21

What forms the outer fibrous layer of the eye?

Answer 21

Sclera and cornea

Question 22

What is the function of the sclera?

Answer 22

Attachment of the eye to extraocular muscles

Question 23

What is the function of the cornea?

Answer 23

Light refraction

Question 24

Which bones form the orbit?

Answer 24

Frontal, zygomatic, sphenoid, maxilla, lacrimal and ethmoid

Question 25

Why can retinal detachment occur?

Answer 25

Retina is derived from ectoderm but choroid is derived from mesoderm

Question 26

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

Answer 26

Loss of bloodflow to retina

Question 27

Why is photophobia seen in meningitis?

Answer 27

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

Question 28

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

Answer 28

Venous drainage allowing retrograde infection

Question 29

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

Answer 29

Pia mater, arachnoid mata and dura mata

Question 30

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

Answer 30

It is a brain fact not a proper nerve

Question 31

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

Answer 31

Keeps it spherical

Question 32

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

Answer 32

Supply nutrients to the lens

Question 33

Where is the anterior chamber of the eye found?

Answer 33

Between cornea and iris

Question 34

Where is the posterior chamber of the eye located?

Answer 34

Between the iris and ciliary processes

Question 35

What does the anterior segment contain?

Answer 35

Aqueous humour

Question 36

What produces aqueous fluid?

Answer 36

Ciliary body

Question 37

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

Answer 37

Moves through the iris

Question 38

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

Answer 38

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

Question 39

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

Answer 39

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

Question 40

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

Answer 40

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

Question 41

What is open-angle glaucoma?

Answer 41

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

Question 42

Describe the passage of tears.

Answer 42

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

Question 43

Where is the palpebral conjunctiva found?

Answer 43

On the inside of the eyelid

Question 44

Where is the bulbar conjunctiva found?

Answer 44

Film covering the eye surface up to the limbus

Question 45

In which conjunctiva can anaemia be identified?

Answer 45

Palpebral

Question 46

What is he function of the eyelid?

Answer 46

To protect against injury, excessive light and dryness

Question 47

In conjunctivitis, is the sclera implicated?

Answer 47

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

Question 48

What is a myobium cyst?

Answer 48

Painless swelling of the tarsal gland

Question 49

What is the treatment for a myobium cyst?

Answer 49

Hot compress

Question 50

What is a stye?

Answer 50

Infection of the ciliary gland (usually staph aureus)

Question 51

Why might Abx be given for a stye?

Answer 51

To prevent retrograde infection

Question 52

What is the palpebral fissure?

Answer 52

Distance between the upper and lower eyelids

Question 53

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

Answer 53

Nodules, hyperaemia, discolouration

Question 54

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

Answer 54

Colour, nodules, vascularity

Question 55

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

Answer 55

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

Question 56

Where is the palpebral part of obicularis oculi found?

Answer 56

In the eyelid