Week 1 - A - Anatomy of the orbit and eye

Question 1

What bone forms the inferolateral margin of the orbital?

Answer 1

The zygomatic bone

Question 2

What bone forms the superior margin of the orbit?

Answer 2

The frontal bone

Question 3

What bone forms the inferiormedial margin of the orbit?

Answer 3

The maxillary bone

Question 4

From medial t lateral state the bones So the: blue, yellow then pink

Answer 4

Blue bone - lacrimal bone Yellow - ehtmoid bone Pink - sphenoid bone

Question 5

What is the hole in sphenoid bone? - lying immediately lateral to the ethmoid bone

Answer 5

This is for the optic canal

Question 6

The ethmoid air cells (sinus) lie behind the ethmoid bone, where does the ethmoid sinus drain? (remember the ethmoid air cells have a posterior, anterior and middle)

Answer 6

Posterior ethmoidal air cells - superior meatus Anterior ethmoidal air cells - semilunar hiatus of middle meatus Middle ethmoidal air cells - ethmoidal bulla of middle meatus

Question 7

thin, semitransparent mucous membrane that covers the posterior surface of the eyelids and is then reflected onto the eyeball

Answer 7

This is the conjuctivae It is non-keratinized stratified columnar epithelium with goblet cells

Question 8

What is the foramina just below the orbit in the maxillary bone? What nerve passes through here that provides sensory innervation to the skin of the lower eyelid, side of the nose, moveable part of nasal septum, anterior cheek and upper lip?

Answer 8

The infra-orbital foramen The ifra-orbital branch of the maxillary division of the trigeminal nerve passes through here

Question 9

The eyelids contain glands which secrete an oily substance to stop the evaporation of tears What is this substance known as

Answer 9

Meibum Produced by the tarsal glands (aka the meibomian glands)

Question 10

The arrows pointing towards the yellw and green in the middle of the picture are what?

Answer 10

Pointing towards yellow - the tarsal gland (meibomian gland) produces meibum Pointing towards green - tarsal plate

Question 11

What is the function of the tarsal plate?

Answer 11

Contributes towards support of the eyelid

Question 12

What muscles are responsible for the movements of the eyeball and superior eyelid?

Answer 12

The extra-ocular muscles

Question 13

What muscles causes elevation of the upper eyelid?

Answer 13

The levator palpabrae superioris

Question 14

What is the concentric muscle of facial expression? (supplied by CN VII) What is its function?

Answer 14

The orbicularis oculi Closes the eylid when contracting and sweeps tears across the eyeball and on its way to drainage via the punctum

Question 15

What glands produce tears? Where are they situated?

Answer 15

Lacrimal gland - situated int he superiolateral region of the orbit

Question 16

What is the function of tears?

Answer 16

Tears lubricate the eyes and capture dirt and then drain them into the nasal cavity

Question 17

After tears are produced and travel across the cornea (helped by orbicularis oculi moving the eyelid), how do they travel to the nasolacrimal duct?

Answer 17

Tears are produced by lacrimal gland then go to - cornea - then through the lacrimal punctum to the lacrimal canaliculi (superior and inferior) - the lacrima canaliculi connects to the lacrimal sac which connects to the nasolacrimal duct

Question 18

Where does the nasolacrimal duct drain?

Answer 18

Drains into the inferior meatus on the lateral wall of the nasal cavity

Question 19

What nerve supplies the lacrimal gland?

Answer 19

The greater petrosal nerve - branch of the facial nerve (CN VII)

Question 20

Are glands usually supplied by sympathetic or parasympathetic? What are the parasympathetic cranial nerves?

Answer 20

Usually by parasympathetic apart from the sweat glands which are sympathetic CN III - oculomotor nerve CN VII - facial nerve CN IX - glossopharngeal nerve CN X - vagus nerve

Question 21

What membrane covers the cornea and the sclera of the eyeball? Mucous membrane

Answer 21

The conjunctivae - non-keratinized stratified columnar epithelium with goblet cells

Question 22

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Answer 22

The conjunctivae Diagnosis For A - allergic conjunctivitis For B - infective conjunctivitis Pus makes B likley to be infective (probably bacterial)

Question 23

What are the three layers of the eyeball? What composes the layers?

Answer 23

Outer fibrous layer - sclera with cornea in middle Middle vascular layer - choroid (uvea), ciliary body, iris Inner layer (nervous and pigmented) - retina

Question 24

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Answer 24

1 - cornea 2 - anterior chamber 3 - pupil 4 - iris 5 - sclera 6.Suspensory ligaments of the lensv(posterior camber found between the iris and suspensory ligaments of the lens) 7 - lens 8- ciliary muscles 9 - sclera

Question 25

Where do the extra-ocular muscles attach? Makes up 85% of the fibrous layer of the eye

Answer 25

The sclera comprises the majority of the fibrous layer (approximately 85%). This is where the extra-ocular muscles attach

Question 26

What is the transparent layer at the front of the eye?

Answer 26

The cornea

Question 27

The vascular layer of the eye lies underneath the fibrous layer What does it consist of?

Answer 27

Consists of the choroid , the ciliary body (containing the muscles) and the iris

Question 28

What attaches the ciliary muscles to the lens of the eye?

Answer 28

Zonular fibres attach the ciliary body to the lens Zonular fibres also known as suspensory ligament of the lens

Question 29

What happens to the shape of the lens when the ciliary muscles contract? What is this process known as?

Answer 29

When the ciliary muscles contract, the suspensory ligaments relax allowing the lens to widen - near vision When the ciliary muscles relax, the suspensory ligaments become taught causing the lens to flatter (distant vision)

Question 30

What is situated between the lens and cornea with a gap for the pupil in the middle?

Answer 30

The iris

Question 31

Smooth muscle fibres of the iris cause constriction of the pupil What provides parasympathetic innervation to the iris cons

Answer 31

The parasympathetic fibres of the oculomotor nerve (CN III)

Question 32

When do the constrictor muscle of the pupil work?

Answer 32

Works in bright light as not as much light is needed to enter the eye

Question 33

What is the muscle of the iris under sympathetic control that is used to dilate the pupil in dim light?

Answer 33

The dilator pupillae of the iris

Question 34

What is the area of most distinct vision of the eye?

Answer 34

The fovea of the eye - located in the macula

Question 35

What are the six extra-ocular muscles?

Answer 35

Superior oblique - attaches to lateral upper side of the eye Inferior oblique - attaches to lateral underside of eye Superior rectus Middle rectus Lateral rectus Inferior rectus

Question 36

Where do the extra-ocular rectus muscles of the eye move the eye?

Answer 36

Superior rectus - moves eye superiorly and medially (up and in) Inferior rectus - moves eye inferiorly and medially (down and in) Lateral rectus - abducts eye Medial rectus - adducts eye

Question 37

Where do the superior oblique and inferior oblique muscles move the eye?

Answer 37

Superior oblique moves eye inferiorly and laterally (down and out) (remember tramp is down and out) Inferiorly oblique moves eye superiorluy and laterally (up and out)

Question 38

What does the superior oblique pass through (pully) and what is its nerve supply?

Answer 38

Passes through the trochlea and is supplied by the trochlear nerve

Question 39

What does the lateral rectus cause and what supplies it?

Answer 39

Causes abduction (lateral) of the eyeball Supplied by CN VI - abducent nerve

Question 40

What is the nerve supply of all 6 extra occular nerves? What is the nerve supply of the levator palpabrae superioris?

Answer 40

\* Superior, medial and inferior rectus + Inferior oblique - oculomotor nerve \* \* Superior oblique muscle - trochlear nerve (causes eye to move down and out) (inferolaterally) \* Lateral rectus - abducent nerve (causes abduction(lateral movement) Levator palpabrae superioris supplied by CNIII (oculomotor nerve)

Question 41

Clinical testing of the eye slightly differs from the normal movements of the eye Explain how you would test each of the obliques

Answer 41

Testing Superior oblique muscle - ask patient to move eye medially and then inferiorly (ends up with down and in) Inferior oblique muscle - as patient to move eye medially and then superiorly (up and in)

Question 42

When testing the obliques, the superior oblique is located on the superolateral aspect of the eye - therefore moving the eye medially can isolate the superior oblique if you then move the eye downwards What surface of the eye is the inferior oblique located on? how is it tested?

Answer 42

Located on inferolateral surface so once moving the eye medially, contracting of the inferior oblique will cause the eye to go upwards

Question 43

What direction do you ask the patient to test the eye for the lateral and medial rectus?

Answer 43

For lateral - laterally For medial - medially

Question 44

What movememnt for superior and inferior rectus?

Answer 44

For superior -ask patient to move eye laterally and the superiorly (up and out) For inferior rectus - ask patient to move eye laterally and inferiorly (down and out)

Question 45

60 year old patient attends your opthamology for evaluation of his ptsosis Which affected muscle is most likely to be the cause?

Answer 45

Ptosis, also known as blepharoptosis, is a drooping or falling of the upper eyelid Muscle cause is levator palpabrae superioris

Question 46

22 year old has been punched upper right cheek Indicaticates a inferiorlateral fracture Which bone?

Answer 46

Inferolateral fracture of orbit is zygomatic bone

Question 47

Would like to test CN IV – following movements of your finger, which directions hould the eye move to best test the function?

Answer 47

Testing the superior oblique muscle of the eye Ask patient to move eye medially and then inferiorly (So down and in)

Question 48

Eye lid has dropped, eye ball is slightly depressed and abducted (down and out) Which nerve is damaged?

Answer 48

As the supeiro oblique eye movement is unopposed it is working Therefore it is oculomotor

Question 49

State the normal movements of the superior oblique muscle and state how to test? Do the same for the inferior oblique?

Answer 49

Superior oblique normal movement - moves eye down and out (inferolaterally) \* Testing - move eye medially then inferiorly, (down and in) Inferior oblique normal movement - moves eye up and out (superolaterally) \* Testing - move eye medially then supiorly

Question 50

Name the two muscles that depress the eye and the two muscles that elevate the eye?

Answer 50

Inferior rectus Superior oblique These two muscles depress the eye Inferior oblique Superior rectus These two muscles elevate the eye