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Head and Neck Anatomy Y1 and Y2 > Ophthamology > Flashcards

Ophthamology Flashcards

1
Q

What 6 bones is the orbit made up of?

A 
Frontal
Zygomatic
Maxillary 
Sphenoid 
Ethmoid 
Lacrimal
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2
Q

What bones have orbital plates? Why is this relevant?

A

The frontal bone, maxillary and ethmoid have orbital plates which are flatter they are thin walled and therefore fracture easily

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3
Q

The optic canal is located _____1_____ for passage of ________2__________

A

1) posteromedially

2) optic nerve and ophthalamic artery

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4
Q

Superior orbital fissure is formed by? What nerves are found going through this?

A

the gap between the greater and lesser wings of the sphenoid bone
cranial nerves responsible for the movement of the eye are found coming through here (3,4 and 6)
and CNV1

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5
Q

The shape of the orbit is described as being a _______

What is the apex and the base?

A

pyramid
Apex is at the optic canal and base is anterolaterally
Base is a combination of medial, lateral, superior and inferior margins

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6
Q

Why is the eye well protected?

A

Eye is very well protected due to superior margin overhanging inferior and the bones that surround are quite tough

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7
Q

Describe a blow-out fracture of the orbit? What is a complication?

A

There is a fracture of one of the walls of orbit but the orbital rim remains intact. This is typically caused by a direct blow to the central orbit from a fist or ball. If impact around the bony orbit is strong enough pressure can be transferred to the thinner bones and will get fracture of the thinner bones.

Trap door fracture, fracture of the orbital floor where the inferiorly displaced blowout fracture recoils back to its original position and potentially entraps contents of the orbit.

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8
Q

What is the most external part of the eyelid? What is the function?

A

Orbicularis oculi muscle which is responsible for closing the eyelids

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9
Q

Describe what is in the deeper layer of the eyelid?

A

Superior and inferior tarsus
Orbital septum
Palpebral ligaments

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10
Q

Describe the orbital septum and its function?

A

The orbital septum is a thin, fibrous membrane that serves as a barrier between the superficial lids and the orbit.

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11
Q

Describe the tarsus of the eyelids and their function?

A

There are two plates; the superior tarsus (upper eyelid) and inferior tarsus (lower eyelid). They act to form the scaffolding of the eyelid, and are composed of dense connective tissue. The superior tarsus also acts as the attachment site of the levator palpebrae superioris.

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12
Q

The lacrimal gland produces lacrimal fluid and has parasympathetic innervation originating from branches of?

A

Facial nerve- CN7

Greater petrosal nerve

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13
Q

Lacrimal gland is located _____1____ in the orbit. Fluid washes over eye and is pushed in a ___2__ angle and drains through ____3______ into ___4____ and then into ____5_____ duct eventually into _____6________

A

1) superolaterally (just below eyebrow)
2) medial
3) lacrimal punta (small opening- dot on eyelid)
4) lacrimal sac
5) nasolacrimal
6) inferior nasal meatus

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14
Q

How many extra ocular muscles are there? What are they?

A

Seven

4 rectus muscles: superior, inferior medial and lateral rectus muscles
2 oblique muscles: superior oblique and inferior oblique
1 levator palpebrae superioris

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15
Q

All extra ocular muscles apart from _____ insert onto the sclera

A

Levator Palpebrae Superioris which inserts onto the skin and tarsus of superior eyelid

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16
Q

All rectus muscles originate from _______ and insert onto ______

A

common tendinous ring

Sclera

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17
Q

The superior oblique muscle originates from ___1__ and inserts onto ____2_____

A

1) sphenoid bone

2) sclera

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18
Q

The inferior oblique muscle originates from ___1__ and inserts onto ____2_____

A

1) orbital plate of maxilla

2) sclera

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19
Q

The levator palpebrae superioris muscle originates from ___1__ and inserts onto ____2_____

A

1) lesser wing of sphenoid

2) skin and tarsus of superior eyelid

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20
Q

Describe the trochlea in the orbit?

A

The trochlea of superior oblique is a pulley-like structure in the eye. The tendon of the superior oblique muscle passes through it. Situated on the superior nasal aspect of the frontal bone, it is the only cartilage found in the normal orbit.

NOTE THAT THE TROCHLEAR NERVE ONLY INNERVATES SUPERIOR OBLIQUE WHICH HAS A TROCHLEA!

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21
Q

Describe the innervation of the extraocular muscles?

A

Lateral Rectus= CN6 - the abducent nerve because it ABDUCTS the eye
Superior Oblique= CN4- the trochlea nerve because it HAS A TROCHLEA
All others= CN3- oculomotor - CLUE IN THE NAME

LR6 SO4 AO3 (apparently it’s catchy?)

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22
Q

What is the lacrimal lake?

A

pool of tears in the lower conjunctival cul-de-sac, which drains into the opening of the tear drainage system

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23
Q

What is the lacrimal papilla and punctum?

A

In medical terms, the lacrimal papilla is a small conical elevation on the margin of each eyelid at the basal angles of the lacrimal lake. Its apex is pierced by a small orifice, the lacrimal punctum where fluid drains into the lacrimal sac.

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24
Q

What is the iris?

A

coloured part of the eye that controls the size of the pupil in the middle

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25
Q

What is the pupil?

A

a hole located in the center of the iris of the eye that allows light to strike the retina.

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26
Q

What is the sclera?

A

white of the eye, opaque, fibrous, protective, outer layer of the human eye containing mainly collagen and some elastic fibre. The sclera is completely covered in conjunctiva.

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27
Q

What is the conjunctiva?

A

The conjunctiva is a tissue that lines the inside of the eyelids and covers the sclera (the white of the eye)

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28
Q

What is the cornea?

A

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber.

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29
Q

What is the conjunctival fornix?

A

Where the eyelid meets the conjunctiva

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30
Q

What is the limbus?

A

border of the cornea and the sclera

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31
Q

What are the three main layers of the eye?

A

Fibrous outer layer
Uvea- vascular, middle layer (iris, ciliary body and choroid)
Retina- photosensitive inner layer

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32
Q

The Anterior Segment of the eye is the area _______ and it is divided into ___________

A 
in front of lens
divided into:
anterior chamber (between cornea and iris)
posterior chamber (between iris and suspensory ligaments)
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33
Q

The Posterior Segment is the area _______ and contains _______

A

behind lens

contains vitreous body and vitreous humour

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34
Q

The anterior chamber is filled with _____1_____ which is produced by ___2______ and provides nutrients to ____3____ The outflow of this is through the trabecular meshwork and canal of _____4____ Any factor that impedes this outflow will increase ____5___

A

1) aqueous humor
2) ciliary body
3) avascular cornea
4) Schlemn
5) Intraocular pressure

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35
Q

The vitreous humour/ body fills the cavity between the ________ It has a role in _________

A

retina and the lens

protecting eye and helping it hold it’s shape

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36
Q

The blood supply of the eye is via the _____ which is a branch of _______

A

ophthalmic artery

internal carotid artery

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37
Q

The central artery of the retina and vein (branches of ophthalmic artery) travel in the ___1____ and are the only ______2________

A

1) optic nerve

2) artery and vein to the retina

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38
Q

The optic disc is the point of formation of _______

A

the optic nerve- CN2

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39
Q

What is the macula?

A

Sensitive spot in the centre of retina that has the greatest density of cone cells

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40
Q

What is the fovea?

A

centre of the macula
depression, 1.5mm diameter
area of most acute vision

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41
Q

Describe the blind spot in the human eye?

A

Small portion of the visual field of each eye that corresponds to the position of the optic disc within the retina. There are no photoreceptors in the optic disc and, therefore, there is no image detection in this area.

42
Q

Explain the visual pathway?

A

Light from objects in the left visual field strike the nasal retina of the left eye and the temporal retina of the right eye. Whilst light from the right visual field strikes the nasal retina of the right eye and the temporal retina of the left eye.

At the optic chiasm the nerve fibres arising from the nasal retina cross to opposite sides of the brain, nerve fibres from temporal retina do not. This mean that light from the left visual field is process in the right primary visual cortex and light from the right visual field is processed in the left primary visual cortex. Lower and upper fields also cross.

Basically if seeing something from left side left eye goes to nasal so it can cross to right but right eye goes to temporal so it stays on right.

43
Q

What are the three axes of the eye?

A

Vertical - abduction / adduction
Transverse - elevation/ depression
Anteroposterior - extorsion / intorsion

44
Q

What occurs around the vertical axis?

A

abduction/adduction

direction of gaze

45
Q

What occurs around the transverse axis?

A

elevation/depression

direction of gaze

46
Q

What occurs around the anteroposterior axis?

A

intorsion/extorsion

superior pole of eyeball

47
Q

What is the action of levator palpebrae superioris?

A

Elevates the superior eyelid

48
Q

What is the action of the superior oblique muscle?

A

Abducts, depresses and medially rotates eyeball

49
Q

What is the action of the inferior oblique muscle?

A

Abducts elevates and laterally rotates eyeball

50
Q

What is the action of the superior rectus muscle?

A

Elevates adducts and and rotates eyeball medially

think overall it adducts to pull back into proper plane

51
Q

What is the action of the inferior rectus muscle?

A

Depresses, adducts and rotates eyeball laterally

think overall it adducts to pull back into proper plane

52
Q

What is the action of the medial rectus muscle?

A

Adducts the eyeball

53
Q

What is the action of the lateral rectus muscle?

A

Abducts the eyeball

54
Q

How can you clinically test the lateral rectus muscle?

A

Abduction of the eye

55
Q

Explain how you can clinically test the superior rectus muscle?

A

Elevate eye in abduction

this is because it cannot do adduction or rotate medially when eye fully abducted so definitely testing this muscle

56
Q

Explain how you can clinically test the inferior rectus muscle?

A

Depress the eye in abduction

this is because cannot adduct or rotate laterally so know testing this muscle

57
Q

Explain how you can clinically test the medial rectus muscle?

A

Adduction of the eye

58
Q

Explain how you can clinically test the inferior oblique muscle?

A

Elevate eye in adduction

59
Q

Explain how you can clinically test the superior oblique muscle?

A

Depress eye in adduction

60
Q

Which muscles can depress the eye?

A

Superior oblique and inferior rectus

These antagonise each other as rotators

61
Q

Which muscles can elevate the eye?

A

Superior rectus and inferior oblique

These antagonise each other as rotators

62
Q

What nerve gives sensory innervation to the face?

A

Trigeminal nerve

63
Q

Name a somatic reflex of the eye?

A

Corneal reflex/ blink reflex

64
Q

What is the corneal reflex/ blink reflex?

A

Blinking of eyes elicited by stimulation of the cornea

65
Q

Describe the sensory afferent and motor efferent limbs of the corneal reflex?

A

Sensory: APs conducted by CNV1 when feel something touch the cornea
Motor: Action potentials conducted via CN VII
To eyelid part of orbicularis oculi

66
Q

Name 4 autonomic reflexes of the eye?

A

wide eye opening of fight or flight
pupillary light reflex
accommodation reflex
lacrimation reflex

67
Q

Sympathetic innervation will do what 4 things to the eye?

A

Open eyes wider
Get more light into eyes
Focus on objects further away
Potentially involved in emotional tears

68
Q

Parasympathetic innervation will do what 3 things to the eye?

A

Get less light into eye
Focus on near objects
Reflex lacrimation

69
Q

Parasympathetic innervation ___1___ the pupil and sympathetic innervation ___2____ the pupil

A

1) constricts

2) dilates

70
Q

What muscle is responsible for pupil constriction?

A

Sphincter pupillae

71
Q

What muscle is responsible for pupil dilation?

A

Dilator pupillae

72
Q

Special sensory (afferent) limb of the pupillary light reflex is ____1____ and conducted by __2__. CNS connections occur in the __3____ The motor limb of the reflex is __4___ via ___5___.

A

1) ipsilateral
2) CN II
3) midbrain
4) bilateral (consensual vs direct eye)
5) CNs III

73
Q

Describe the lens accommodation reflex in far vision?

A

the ciliary muscle relaxes in “far vision”

ligament tightens & lens flattens to focus on an object in the distance

74
Q

Describe the lens accommodation reflex in near vision?

A

the ciliary muscle contracts in “near vision”

ligament relaxes & lens becomes spherical to focus on near objects

75
Q

What are the three types of tears? Purpose?

A

Basal > for health of avascular cornea
Reflex > extra tears in response to mechanical or chemical stimulation
Emotional

76
Q

What is the sensory and motor limb in reflex tears?

A

afferent limb is CN V1 from cornea/conjunctiva

efferent limb is parasympathetic axons originating from CN VII (via the pterygopalatine ganglion)

77
Q

Sympathetic innervation exits spinal cord from levels?

A

T1-L2

78
Q

Describe sympathetic innervation to the orbit?

A

Exits at T1

Passes all the way up the chain into the cervical region and synapses in the superior cervical ganglion

79
Q

What ganglia is involved in parasympathetic innervation to the orbit? What nerve is it related to?

A

Ciliary ganglion

Oculomotor nerve

80
Q

What are the meninges?

A

protective coverings surrounding brain and spinal cord

81
Q

3 layers of the meninges?

A

Dura mater
Arachnoid mater
Pia mater

82
Q

Describe dura mater?

A

Outer layer

hard, tough covering, contains dural venous sinuses

83
Q

Describe arachnoid mater?

A

Middle layer

has arachnoid granulations

84
Q

Describe pia mater?

A

Inner layer

mater that adheres to the brain

85
Q

What contains the CSF?

A

The subarachnoid space (space between arachnoid mater and pia mater)
Ventricles of the brain

86
Q

You can obtain sample of CSF from lumbar puncture at what levels?

A

L3/L4 or L4/5 IV disc

87
Q

CSF is produced in?

A

The choroid plexus

88
Q

Why is ICP important to know about in ophthalmology?

A

65-75% of patients with ICP will report visual problems
transient blurred vision
double vision
loss of vision
papilloedema (swelling of optic disc due to increased ICP)
pupillary changes

89
Q

Why is the optic nerve particularly effected by raised ICP?

A

The optic nerves are technically just continuations of the CNS tract so are covered in meninges so any raised ICP will be transmitted along the subarachnoid space in the nerve sheath.

90
Q

Why is the oculomotor nerve susceptible to damage in increased ICP?

A

Due to its position

91
Q

If problems with oculomotor nerve due to increased ICP what will not work?

A

Paralysis of somatic motor innervation: 4 extra-ocular muscles and eyelid (inferior oblique, LPS, medial and inferior rectus, superior rectus). Paralysis of parasympathetic innervation sphincter of pupil

92
Q

What will an eye with paralysed oculomotor nerve look like? Explain

A

lose/slowness of pupillary light reflex (loss of parasympathetics), dilated pupil, ptosis (can’t use LPS), eye turned inferolaterally (can only use the superior oblique and the lateral rectus muscle when try to look straight on)

93
Q

When you ask a patient with a paralysed oculomotor nerve to look straight ahead what will happen?

A

They will look down and out
Inferolaterally
Can only use superior oblique and lateral rectus

94
Q

Why is the trochlea nerve susceptible to damage from increased ICP?

A

Due to its long length and long intracranial route

95
Q

Which cranial nerve has the longest intracranial course?

A

Trochlea nerve

96
Q

What is paralysed if trochlea nerve is damaged?

A

The superior oblique muscle

97
Q

What will happen in a patient’s eye if lose the function of the trochlea nerve?

A

When ask patient to look to the right the eye moves superomedially as inferior oblique is unopposed so it can’t stay in proper plane.

98
Q

What is paralysed if the abducent nerve is damaged?

A

Lateral rectus

99
Q

What will happen in a patient’s eye if they lose the function of the abducent nerve?

A

Eye cannot move laterally in horizontal plane

Medial deviation of the eye

100
Q

What nerve is paralysed… when patient is asked to look straight on their eye moves inferolaterally?

A

Oculomotor nerve

101
Q

What nerve is paralysed… when patient is asked to look to the right the eye move superomedially?

A

Trochlea nerve

102
Q

What nerve is paralysed… there is medial deviation of the eye?

A

Abducent nerve

Head and Neck Anatomy Y1 and Y2 (9 decks)

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