Eye

Question 1

Which bone makes up the roof of the orbit?

Answer 1

Orbital plate of the frontal bone

Question 2

Which bone makes up the floor of the orbit?

Answer 2

The maxilla

Question 3

Which structure is being indicated here?

Answer 3

Supraorbital notch/foramen

Question 4

Which structures are being indicated here?

Answer 4

1. Optic canal
2. Superior orbital fissure

(Both part of sphenoid bone)

Question 5

Which structures of which bone are indicated here?

Answer 5

Infraorbital canal and foramen of maxilla

Question 6

Which bone of the orbit is indicated in blue?

Answer 6

Lacrimal

Question 7

Which bone of the orbit is indicated in yellow?

Answer 7

Orbital plate of ethmoid bone

Question 8

Which structure protects the eye from a direct blow?

Answer 8

The orbital margins

Question 9

Which bones tend to fracture in an orbital blowout fracture and why?

Answer 9

Orbital plate of ethmoid bone (medial wall)

Maxilla (floor)

They are extremely thin - 0.5-1mm thick

Question 10

How does a fractured zygoma tend to displace?

Answer 10

Tends to rotate medially to the floor of the orbit

Question 11

Which structure is held within the infraorbital canal?

Answer 11

Infraorbital NVB

Question 12

Which muscle makes up the ‘sphincter’ of the eye and what movement does it allow?

Answer 12

Obicularis oculi

Allows us to screw up the eyes

Question 13

Which two ligaments attach the eyelid to the orbital rim?

Answer 13

Medial and lateral palpebral ligaments

Question 14

Which structure is being indicated here and what is its function?

Answer 14

Tendon of levator palpebrae superioris

Contains skeletal and smooth muscle to elevate the superior eyelid

Question 15

Which structures are being indicated here?

Answer 15

Superior and inferior tarsal plates

Question 16

What is the orbital septum?

Answer 16

A sheet of fascia attaching to the peripery of the orbital rim

Question 17

What does the orbital septum do?

Answer 17

Assists with preventing the spread of infection from superficial (periorbital cellulitis) to deep (orbital cellulitis)

Question 18

What is the conjunctival fornix?

Answer 18

Where the conjunctiva is reflected off the sclera and onto the internal aspect of the eyelid

Question 19

What is the name given to the orbital opening into the nasolacrimal duct?

Answer 19

Puncta

Question 20

What is the name of the junction between the cornea and the sclera?

Answer 20

The limbus

Question 21

What is the parasympathetic supply of the lacrimal gland?

Answer 21

CN VII

Question 22

What is the name of the superior end of the nasolacrimal duct?

Answer 22

Lacrimal sac

Question 23

Where should corneal reflections be seen normally?

Answer 23

Slightly medial i.e. nasal side of the pupil (as opposed to temporal side)

Question 24

What are the two parts of the outer fibrous layer of the eye?

Answer 24

Sclera

Cornea

Question 25

What is the function of the sclera?

Answer 25

Protects the eye Provides attachment for the extraocular muscles

Question 26

What is the function of the cornea?

Answer 26

Provides 2/3 of the eye's refractive power

Question 27

What are the three parts of the uvea?

Answer 27

The iris The ciliary body The choroid

Question 28

What is the vascular layer of the eye?

Answer 28

The uvea

Question 29

What is the function of the ciliary body of the eye?

Answer 29

Control of the iris and the shape of the lens Secretion of aqueous humour

Question 30

What is the photosensitive layer of the eye?

Answer 30

The inner retina

Question 31

What is the function of the choroid?

Answer 31

Nutrition and gaseous exchange for the other layers

Question 32

Which is the 'vascular' layer of the eye?

Answer 32

Choroid

Question 33

What is the vitreous body?

Answer 33

A structure in the posterior segment which holds a clear gel consisting of ~98% water that provides pressure to hold the retina in place

Question 34

What is the anterior chamber?

Answer 34

The space containing aqueous humour between the cornea and the iris

Question 35

What is the posterior chamber?

Answer 35

Contains the lens and aqueous (humour) and is located between the iris and the vitreous body

Question 36

What is the function of the ciliary body?

Answer 36

Controls the refractive shape of the lens and the secretion of aqueous humour

Question 37

What is the area of most acute vision in the eye?

Answer 37

The fovea centralis in the macula - contains the largest density of cones

Question 38

What is the only vein that drains the retina?

Answer 38

Central vein of the retina

Question 39

Which structures are being indicated here?

Answer 39

Question 40

How do the opthalmic veins drain the orbit?

Answer 40

Anteriorly: orbit drains into the facial vein Posteriorly: inferior opthalmic vein drains mainly into superior opthalmic vein, and drains into the cavernous sinus

Question 41

Through which structure does the superior opthalmic vein drain into the cavernous sinus?

Answer 41

Superior orbital fissure

Question 42

What is the retinal blood supply provided by?

Answer 42

The central retinal artery The central retinal vein

Question 43

Which artery do the ciliary arteries branch from?

Answer 43

Opthalmic artery

Question 44

What is the result of an occlusion of a retinal artery branch/branch retinal vein?

Answer 44

An area of visual loss corresponding to the area of ischaemia

Question 45

What is the result of a complete interruption of flow to the central retinal artery or vein?

Answer 45

Monocular blindness

Question 46

Which structure does the 'blind spot' of the visual field correspond to?

Answer 46

The optic disc

Question 47

What are the three layers of the retina posterior - anterior?

Answer 47

1. Photoreceptors 2. Ganglion cells 3. Axons of ganglion cells

Question 48

Where in the brain are the visual cortices?

Answer 48

In the occipital lobes

Question 49

Where in the visual pathway does synapse occur?

Answer 49

Right and left sides of the thalamus

Question 50

Does light picked up in the temporal retina cross over in the optic chiasm as the action potentials travel in the visual pathway?

Answer 50

No

Question 51

Does light picked up in the nasal retina cross over at the optic chiasm as the action potential travels along the visual pathway?

Answer 51

Yes

Question 52

Where do the rectus muscles of the eye all originate and insert?

Answer 52

They have a common origin - common tendinous ring attached to the bones surrounding the optic canal All insert into the sclera just posterior to the cornea

Question 53

What are the 7 extraocular muscles?

Answer 53

4 rectus - superior, inferior, lateral and medial 2 obliques - superior and inferior Levator palpebrae superioris

Question 54

What is the trochlea of the eye?

Answer 54

A fibrous structure used as a pulley by the superior oblique muscle of the eye It attaches superomedially to the rim of the eye

Question 55

What is the motor innervation to the extraocular muscles?

Answer 55

LR6 SO4 AO3 Lateral rectus - abducens Superior oblique - trochlear All others - oculomotor

Question 56

Which muscle abducts the eye?

Answer 56

Lateral rectus

Question 57

If a patient is asked to look to the left, which muscles in each eye are working?

Answer 57

Left eye - lateral rectus Right eye - medial rectus

Question 58

What movement of the eye does the inferior oblique provide?

Answer 58

Elevates from the aDDucted position

Question 59

What movement of the eye does the superior oblique provide?

Answer 59

Depresses the eye from the aDDucted positon

Question 60

Which muscles are working in each eye if the patient is asked to look left and upwards?

Answer 60

Left eye - lateral rectus and superior rectus Right eye - medial rectus and inferior oblique

Question 61

Which muscles are working if the patient is asked to look up?

Answer 61

Both eyes - superior rectus and inferior oblique

Question 62

Which muscles are working if the patient is asked to look down?

Answer 62

Both eyes - inferior rectus and superior oblique

Question 63

What is the general sensory nerve supply to the upper eyelid, the cornea, all the conjunctiva and the the skin of the root/bridge/tip of the nose?

Answer 63

Opthalmic nerve CN V1

Question 64

What nerves are involved in the blink reflex?

Answer 64

Afferent: Cornea - V1 - V - pons Efferent: VII - obicularis oculi

Question 65

How does sympathetic innervation reach the orbit?

Answer 65

Sympathetic fibres exit the spinal cord at T1, and travel upwards to synapse in the superior cervical chain Post synaptic fibres enter the external carotid nerve and internal carotid nerve, attached to the arteries They are carried along the arteries to the orbit

Question 66

What structures are being indicated here?

Answer 66

Question 67

What is the base of skull course of the oculomotor nerve?

Answer 67

Superior orbital fissure

Question 68

Where does the oculomotor nerve connect with the CNS?

Answer 68

Junction between midbrain and pons

Question 69

What is the function of the ciliary nerves?

Answer 69

Supply autonomic axons to the iris to alter diameter of pupil and to change refractive shape of lens

Question 70

What structures are there in the ciliary ganglion?

Answer 70

Presynaptic fibes of CN III Postsynaptic sympathetic fibres from the superior cervical ganglion Postsynaptic fibres from the ciliary ganglion General sensory fibres from the cornea and conjunctiva

Question 71

What are the four autonomic relfexes of the eye?

Answer 71

Pupil dilation/constriction Lacrimation Maximal eyelid elevation Focussing the lens

Question 72

What is the vestibulo-ocular reflex?

Answer 72

Turns the eyes in the opposite direction to a head movement

Question 73

What nerves are involved in the vestibulo-ocular reflex?

Answer 73

Vestibulocochlear VIII Oculomotor III Trochlear IV Abducens VI

Question 74

What is the oculocardiac reflex?

Answer 74

Reflex bradycardia in response to pressure on the eye or tension on extra ocular muscles

Question 75

Which nerves are involved in the oculocardiac reflex?

Answer 75

Opthalmic nerve V1 Vagus X

Question 76

What changes to the eye does sympathetic innervation cause?

Answer 76

Open eyes wider Pupil dilation Focus on far objects ? emotional lacrimation

Question 77

What changes to the eye does parasympathetic innervation cause?

Answer 77

Allow obicularis oculi to work Allow less light into eye Focus on near objects Reflex lacrimation

Question 78

What is a non-physiologically dilated pupil called?

Answer 78

A mydriatic pupil

Question 79

Which muscle allows pupil dilation and what is its origin and insertion?

Answer 79

Dilator pupillae Origin around the external circumference of the iris Insertion around the internal circumference of the iris

Question 80

Which muscle allows constriction of the pupil and where is it located?

Answer 80

Sphincter pupillae Internal circumference of the iris

Question 81

What is a non-physiologically constricted pupil known as?

Answer 81

A miotic pupil

Question 82

What is the special sensory afferent limb of the light reflex?

Answer 82

Optic nerve CN II

Question 83

What is the light reflex called in the stimulated eye and the other eye?

Answer 83

Stimulated - direct light reflex Other - consensual light reflex

Question 84

What is the motor limb of the light relfex?

Answer 84

Oculomotor CN VIII

Question 85

Which structure connects the surface of the lens and the ciliary body?

Answer 85

Suspensory ligament of the lens

Question 86

How does the ciliary body change the shape of the lens to allow the eye to focus on object in the distance?

Answer 86

Ciliary muscle relaxes The suspensory ligament tightens, flattening the lens No parasympathetic inneravation involved

Question 87

How does the ciliary body change the refractory shape of the lens to allow focus on near objects?

Answer 87

Ciliary muscle contracts - parasympathetic innervation Suspensory ligament relaxes and makes the lens spherical