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Ophthalmology > Anatomy > Flashcards

Anatomy Flashcards

1
Q

Label the following diagram showing the bones and features of the bony orbit

A
  1. Orbital plate of frontal bone
  2. Optic canal
  3. superior orbital fissue
  4. Sphenoid bone
  5. zygomatic bone
  6. infraorbital foramen
  7. maxilla
  8. orbital plate of ethmoid bone
  9. Lacrimal bone
  10. nasal bone
  11. supraorbital notch / foramen
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2
Q

What is the shape of the bony orbit

A

pyramidal shape

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3
Q

What is at the apex of the bony orbit?

A

optic canal

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4
Q

What helps to protect the eye from a direct blow?

A

the superior and inferior orbital margin

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5
Q

What is most vulnerable during an orbital blowout fracture?

A

The medial wall and orbital floor - extremely thin

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6
Q

What is the main external muscle of the eyelids?

A

obicularis oculi

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7
Q

Label the following diagram of obicularis oculi

A
  1. Orbital part
  2. Palpebral part
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8
Q

Label the following diagram of the ligaments of the eye

A
  1. Lateral palpebral ligament
  2. Orbital septum
  3. inferior tarsus
  4. medial palperbral ligament
  5. superior tarsus
  6. tendon of levator palpebral
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9
Q

What is the orbital septum?

A

A sheet of fascia

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10
Q

What are the tarsal glands and what do the secrete?

A

They are modified sebaceous glansa embedded in the tarsi - they are involved in lipid secretion

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11
Q

Label the following diagram of the surface anatomy of the eye

A
  1. The location of the lacrimal gland
  2. The limbus - corneoscleral junction
  3. White sclera covered by conjuctiva
  4. The conjuctival fornix
  5. Lower eyelid lined by conjunctiva
  6. inferior lacrimal papilla and punctum
  7. lacrimal lake
  8. a conjuctival vessel
  9. iris - covered by cornea
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12
Q

Which nerve is responsile for the parasympathetc production of lacrimal fluid?

A

CN VII

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13
Q

What are the 3 layers of the eye?

A

Fibrous layer

Vascular layer

Photosensitive layer

(from outer to inner)

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14
Q

What makes up the fibrous outer layer of the eye?

A

sclera - muscle attachment

Cornea

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15
Q

Label the following diagram of the fibrous part of the eye

A
  1. Sclera
  2. Cornea
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16
Q

What 3 components make up the vascular layer (uvea) of the eye?

A

Iris - pupil diameter

Ciliary body - controls iris, shape of lens and secretion of aqueous humour

Choroid - nutrition and gas exchange

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17
Q

Label the following diagram of the uvea (vascular layer)

A
  1. Ciliary body
  2. Iris
  3. choroid
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18
Q

What is the photosensitive layer of the eye?

A

The retina

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19
Q

Where is the anterior segment of the eye?

A

In front of the lens

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20
Q

What are the chambers of the anterior segment? state their boundaries

A

Anterior chamber - between cornea and iris

Posterior chamber - between iris and suspensory ligaments

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21
Q

What does the anterior segment contain?

A

aqueous humour

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22
Q

Where is the posterior segment and what proportion of the eye is posterior segment?

A

behind the lense

2/3rds of the eye

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23
Q

What does the posterior segment of the eye contain?

A

virteous body

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24
Q

Label the following diagram of a slit-lamp view of the anterior segment:

A
  1. A pharmacologically dilated pupil
  2. The corneal reflection
  3. The iris
  4. The location of the iridocorneal angle in the anterior chamber
  5. The limbus - corneoscleral junction
  6. Catarct
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25
Q

What is the ciliary body made from?

A

smooth muscle and blood vessels

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26
Q

Where does the aqueous circulate and what is its function?

A

within the posterior chamber - nourishes the lens

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27
Q

After the aqueous is secreted from the ciliary body and circulated around the posterior chamber, where does it pass?

A

passes through the pupil into the anterior chamber and nourishes the cornea

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28
Q

Where is the aqueous reabsorbed?

A

The aqueous is reabsorbed into the scleral venous sinus at the iridocorneal angle

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29
Q

What is the iridocorneal angle?

A

the angle in “open-angle” & “closed-angle” glaucoma

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30
Q

What is the fundus of the retina?

A

posterior area where light is focussed

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31
Q

Where is the optic disc found?

A

In the fundus of the retina

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32
Q

Where is the point of CN II formation?

A

Optic disc

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33
Q

Where is the only poin of entry/exit for blood vessels of CN II?

A

Optic disc

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34
Q

What are cone cells (cones)?

A

photoreceptor cells associated with colour vission

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35
Q

Where is the macula located?

A

In the fundus of the retina

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36
Q

What is the macula?

A

greatest density of cones

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37
Q

What is the fovea?

A

the center of the macula

depression of 1.55mm diameter

area of most acute vission

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38
Q

Label the following fundoscopy image of the retina

A
  1. temporal retina
  2. nasal retina
  3. macula of retina
  4. branches of retinal vessels
  5. optic disc
  6. the central artery of the retina and central vein of the retina
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39
Q

What can complete interruption of flow in a retinal artery / vein branch result in?

A

Loss of an area of visual field corresponding to the area of ischaemia

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40
Q

What can complete interruption of flow of the central artery (end artery) or vein result in?

A

monocular blindness

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41
Q

What are the 3 layers of the retina) from posterior to anterior

A

the photoreceptors

the ganglion cells

axons of the ganglion cells

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42
Q

Fill in the blanks

The axons in the visual pathway maintain specific spatial relationships to each other:

  • light from objects in the right visual field is processed by the visual cortex
  • light from objects in the lower visual field is processed by the part of the primary visual cortex
A

The axons in the visual pathway maintain specific spatial relationships to each other:

  • light from objects in the right visual field is processed by the left primary visual cortex
  • light from objects in the lower visual field is processed by the upper part of the primary visual cortex
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43
Q

Label the following diagram

A
  1. The Ophthalmic artery
  2. The internal carotid artery
  3. cavernous sinus
  4. pituitary gland
  5. the optic nerve (CN II)
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44
Q

Label the following diagram of arterial blood supply to the eye

A
  1. The internal carotid artery
  2. ophthalmic artery
  3. ciliary arteries - supply the choroid
  4. the central artery of the retina (end artery)
  5. nasal cavity branches - contribute to kiesselbach’s area
  6. forehead (scalp) branches
  7. the central vein of the retina - the only vein draining the retina
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45
Q

Label the following diagram of venous drainage of the eye

A
  1. cavernous sinus via the superior orbital fissure
  2. The optic nerve
  3. The superior ophthalmic vein
  4. A forehead vein
  5. facial vein (orbit drains anteriorly into this vein)
  6. inferior opththalmic vein
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46
Q

What does this picture highlight and what is significant about it?

A

the danger triangle of the face

dangerous in bacterial infections as the veins communicate to cavernous sinus

infection can spread from face to brain

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47
Q

How many extraocular skeletal muscles are there?

A

7

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48
Q

how many rectus muscles are there and what are there names?

A

4 rectus muscles:

superior

inferior

medial

lateral

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49
Q

where do the rectus muscles originate from?

Where do the insert?

A

all originate from the common tendinous ring

all insert onto sclera

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50
Q

how many oblique muscles are there ?

what are their names?

where do they instert?

A

2

inferior and superior oblique

insert onto sclera

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51
Q

What is the name of the muscle that lifts the upper eyelid?

A

levator palpebrae superioris

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52
Q

Label the following diagram of the extraocular muscles

A
  1. inferior rectus
  2. lateral rectus
  3. medial recus
  4. superior rectus
  5. superior oblique
  6. optic nerve
  7. trochlea
  8. levator palpebrae superioris
  9. superior tarsus
  10. inferior oblique
  11. comon tendinous ring
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53
Q

Which nerve provides somatic motor innervation of the lateral rectus?

A

CN VI - abducent nerve

(LR6)

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54
Q

Which nerve provides somatic motor innervation of the superior oblique nerve?

A

CN IV - trochlear nerve

(SO4)

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55
Q

What nerve provides somatic motor innervation to the extraocular muscles (apart from the lateral rectus and superior oblique)

A

CN III - oculomotor nerve

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56
Q

What is the movement of the eyeball in the verticle axis?

A

Abduction / Adduction (away and towards midline)

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57
Q

How can the eyball move in the transverse axis?

A

Elevation and depression

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58
Q

What is the type of movement of the eyeball in the Anteroposterior axis?

A

intorsion (medial rotation)

extorsion (lateral rotation)

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59
Q

What momvement does lateral rectus cause?

What nerve innervates this muscle?

A

Abduction of eyeball

CN VI (abducent)

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60
Q

what eye movement does superior rectus cause?

What nerve innervates this muscle?

A

When in abduction superior rectus can only elevate)

CN III (oculomotor nerve)

follow finger laterally and up

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61
Q

what eye movement does inferior rectus cause?

What nerve innervates this muscle?

A

when in abduction inferior rectus can only depress

CN III - oculomotor nerve

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62
Q

What eyemovent does medial rectus facilitate?

What nerve innervates this muscle?

A

can only adduct eyeball

CN III - oculomotor nerve

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63
Q

What eye movement does inferior oblique facilitate

what nerve innervates this muscle?

A

When in adduction inferior oblique can only elevate

CN III - oculomotor nerve

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64
Q

what eyemovement is facilitated by superior oblique?

what nerve innervates this muscle?

A

when in adduction superior oblique can only depress

CN IV - trochlear nerve

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65
Q

What muscles are involved in pure elevation of the eyeball?

A

superior rectus and inferior oblique

66
Q

what muscles are involved in pure depression?

A

superior oblique and inferior rectus

67
Q

What is the role of the suspensory ligament of the eye?

A

supports both eyes in the same verticle position within the orbit

68
Q

where does the suspensory ligament attach?

A

to the zygoma laterally

69
Q

what can damage to the suspensory ligament result in?

A

diplopia - double vision

70
Q

What is CN V1 and where does it provide general sensory neve supply?

A

Ophthalmic nerve

the upper eyelid

the cornea

all of the conjunctiva

the skin of the root/bridge/tip of the nose

71
Q

What is CN V2 and where does it supply general sensory nerve supply?

A

Maxillary nerve

the skin of the lower eyelid

the skin over the maxilla

the skin of the ala of the nose

the skin / mucosa of the upper lip

72
Q

What is CN V3 and where does it provide a general sensory nerve supply?

A

The mandibular nerve

the skin over the mandible and temperomandibular joint excluding the angle of the mandible

73
Q

Which nerves supply general sensory nerve supply to the angle of the mandible?

A

C2 and C3 spinal nerves

74
Q

In which direction does a fractured zygoma tend to rotate?

What can this lead to?

A

rotates medially towards the floor of the orbit

this can damage the infraorbital NVB within the infraorbital canal –> general sensory deficit of the facial skin

75
Q

How can the blink reflex be clinically tested?

A

using a sterile point of cotton wool gently touch the cornea

76
Q

Outline the blink reflex

A
  • action potentials are conducted centrally via CN V1 to the trigeminal ganglion
  • then in CN V to the pons (afferent [sensory] limb of reflex)
  • there are CNS connections between CN V and CN VII
  • Action potentials are then conducted periperally in CN VII to the eyelid part of obicularis oculi (efferent [motor] limb of reflex)
77
Q

Outline how sympathetic axons travel from the CNS to the orbit - presynaptic part only

A
  • presynaptic sympathetic axons from the CNS descend in the spinal cord a
  • Exit the spinal cord in T1 spinal nerve
  • ascend within the sympathetic trunk
  • synapse in the superior cervical sympathetic ganglion
78
Q

Outline how sympathetic axons travel from the CNS to the orbit - postsynaptic part only

A
  • From the superior cervical ganglion the post synaptic sympathetic axons enter the internal carotid nerve and external carotid nerve
  • They pass onto the surface of the internal and external carotid arteries resepectively
  • They are carried to the organs of the head on the surface branches of these arteries
    • For the orbit an intracranial branch of the internal carotid artery travels on the ophthalmic artery
79
Q

What do the inferior cervical ganglion and the 1st thoracic ganglia form when they fuse?

A

stellate ganglion

80
Q

Label the nerves in this posterior view of the pharynx

A
  1. Right and left internal carotid nerves
  2. left superior cervical sympathetic ganglion
  3. left middle cerrvical sympathetic ganglion
  4. left inferior cervical sympathetic ganglion
  5. The right vagus nerve
81
Q

Which cranial nerves are involved in the parasympathetic system?

A
  • CN III - oculomotor nerve
  • CN VII - facial nerve
  • CN IX - glossopharyngeal nerve
  • CN X - vagus nerve
82
Q

In the sympathetic nervous system what is the presynaptic neurotransmitter?

A

acetylcholine

83
Q

In the sympathetic nervous system what is the the postsynaptic neurotransmitter?

A

noradrenaline

84
Q

In the sympathetic nervous system where is the synapse?

A

in the sympathetic trunk

85
Q

In the parasympathetic nervous system what is the presynaptic neurotransmitter?

A

acetylecholine

86
Q

in the parasympathetic nervous system what is the postsynaptic neurotransmitter?

A

acetylcholine

87
Q

In the parasympathetic nervous system where is the synapse located?

A

Within the organ

88
Q

Where does the oculomotor nevre (CN III) synapse?

A

ciliary ganglion in the orbit

89
Q

Which nerve provides parasympathetic innervation to the lacrimal gland? Where does this nerve synapse?

A

CN VII - facial nerve

synapses in the Pterygopalatine ganglion

90
Q

What nerve provides parasympathetic innervation to the submandibular and sublingual salivary glands?

Where does this nerve synapse?

A

facial nerve CN VII

synapses in the submandibular ganglion

91
Q

which nerve provides parasymapthetic innervation to the parotid salivary gland?

Where does this nerve synapse?

A

glossopharyngeal nerve CN IX

synapses in the otic ganglion

92
Q

Which cranial nerve provides sympathetic innervation to the organs of the neck/chest and abdomen (as far as the midgut)?

A

CN X - the vagus nerve

93
Q

where do the sacral spinal nerves provide parasympathetic innervation?

A

hindgut, pelvis and perineum

94
Q

what type of innervation does CN III supply?

A

somatic motor

parasympathetic (autonomic)

95
Q

What muscles does CN III provide somatic motor innervation to?

A

superior rectus

medial rectus

inferior rectus

inferior oblique

lavator palperbrae superioris

(all extraocular muscle apart from lateral rectus and superior oblique)

96
Q

where does the presynaptic parasympathetic axon of CN III synapse?

A

ciliary ganglion

97
Q

Where does CN III connect to the CNS?

A

near the midline at the junction between the midbrain and pons

98
Q

through which foramen does CN III pass?

(base of skull part of the course)

A

superior orbital fissure

99
Q

which extraocular muscles does the superior branch of CN III supply?

A

superior rectus and levator palpebrae superioris

100
Q

Which extraocular muscles do the inferior branch of CN III supply?

A

Medial rectus

inferior rectus

inferior oblique

(also parasypathetic supply to the ciliary ganglion)

101
Q

State which nerves pass through the ciliary ganglion and state whether or not they synapse.

A

general sensory fibres from the cornea and conjunctiva - doesn’t synapse

postsynaptic sympathetic fibres from the superior cervical ganglion (long cillary nerve) - doesn’t synapse here

Inferior branch of CN III - does synapse here

102
Q

What nervous system do the cilliary nerves belong to? what do they control?

A

autonomic - control diameter of iris and the refractive shape of lens

103
Q

What are the 4 autonomic reflexes of the eye?

A

Maximal eyelid elevation

pupillary dilation / constriction

focussing the lens

lacrimation

104
Q

what is the vestibulo-ocular reflex?

What CNS connections are involved?

A

turns the eyes in the opposite direction to a head movement (to stabilise the gaze on an object during head movements)

CNS connections between CN VII and CNs III, IV and VI (extraoccular muscles)

105
Q

What is the oculocardiac reflex?

What CNS connections are involved?

A

reflex bradycardia in response to tension on the extraocular muscles or pressure on the eye

CNS connections between CN V1 and CN X

106
Q

What are the effects of sympathetic stimulation on the eye?

A

open eyes wider

get more light into eyes - pupil dilation

focus on far objects

emotional lacrimation

107
Q

What are the effects of the parasympathetic system on the eye?

A

allow obicularis oculi to work

get less light into eyes (pupil constricts) - protect retina

focus on near objects

reflex lacrimation - wash away stimulant foreign body and clean the cornea

108
Q

What type of muscle is levator palpebrae superioris?

A

skeletal muscle plus smooth muscle

109
Q

outline how postsynaptic sympathetic fibres reach the levator palpebrae superioris

A
  • the superior cervical sympathetic ganglion
  • the internal carotid nerve the internal carotid plexus
  • axons carried on the ophthalmic artery…
  • and on its branches to the orbital structures

eyes open wider

110
Q

What effect does sympathetic stimulation have on the pupil size?

A

causes dilation

111
Q

What is a non-physiologically enlarged pupil called?

i.e remains large even in bright light

A

mydriatic pupil

112
Q

What can cause a mydriatic pupil?

A

drugs, tumour and disease

113
Q

how are the dilator pupillae fibres arranged?

where do they originate?

where do they insert?

A

radially arranged

originate all around the external circumference of the iris (fixed origin)

insert around the internal circumference of the iris (mobile insertion)

114
Q

What division of the nervous system causes pupillary constriction?

A

the parasympathetic division

115
Q

What is a non-physiologically constricted pupil called?

i.e still constricted in darkness

A

mitotic pupil

116
Q

in what syndrome is a mitotic pupil seen?

A

Horner’s syndrome

117
Q

What is a fixed pin-point pupil a sign of

A

pathological sign of opiate drugs

118
Q

how are the pupillae fibres arranged?

A

sphincter encircling around the internal circumference of iris

119
Q

What is the light reflex in the stimulated eye called?

A

the direct light reflex

120
Q

What is the light reflex in the non-stimulated eye called?

A

the consensual light reflex

121
Q

The special sensory (afferent) limb of the light reflex is carried in the the ipsi/bi/conta lateral CN

A

ipsilateral CN II (optic nerve)

122
Q

the motor limb of the light reflex is ipsi/bi/contra lateral

via CN?

A

bilateral

CN III - oculomotor nerves

123
Q

In the light reflex where in the brain do the CNS connections occur?

A

the thalamus

124
Q

How many neurone chains are involved in the pupillary light reflex?

A

4

125
Q

What are the 1st neurones in the pupillary light reflex?

A
  • the retinal ganglion cells pass via the ipsilateral optic nerve
  • to cross over (decussate) in the optic chiasm
  • then synapse in the pretectal nucleus in the midbrain
126
Q

What are the 2nd neurones in the pupillary light reflex?

A

bilateral

  • located entirely within the midbrain & connect the pretectal nucleus
  • to the next synapse in the Edinger Westphal nucleus (the location of the cell bodies of the parasympathetic axons of CN III)
127
Q

What are the 3rd neurones in the pupillary light reflex?

A

bilateral

pass from the EW nucleus, via CN III then its inferior division, to synapse in the ciliary ganglion

128
Q

What are the 4th neurones in the pupillary light reflex?

A

bilateral

course in the short ciliary nerves to the sphincter pupillae muscles

129
Q

what connects the circumference of the lens and the ciliary body?

what is this structure involved in?

A

the suspensory ligament of the lens

controlling the refractive shape of the lens

130
Q

what structures are involved in controlling the shape of the lens?

A

suspensory ligament of the lens

ciliary body and smooth ciliary muscle (like a sphincter around circumference of ciliary body)

131
Q

choose the correct phrase / word

the ciliary muscle contracts /relaxes in “far vision” (no** parasympathetics) the ligament **tightens** & the lens **flattens to focus on the distance

A

the ciliary muscle relaxes in “far vision” (no/some parasympathetics) the ligament tightens/relaxes & the lens becomes spherical /flattens to focus on the distance

132
Q

choose the appropriate phrase / word:

the ciliary muscle contracts /relaxes in “near vision” (no/some parasympathetics) the ligament tightens/relaxes & the lens becomes spherical /flattens to focus on near objects (reading)

A

the ciliary muscle contracts in “near vision” (some parasympathetics) the ligament relaxes** & the lens **becomes spherical to focus on near objects (reading)

133
Q

how do you clinically asses all 3 components of the accommadation reflex?

A
  1. bilateral pupillary constriction (CNs III)
  2. bilateral convergence - medial rotation of both eyes (CNs III)
  3. bilateral relaxation of the lens

the lens becomes spherical due to contraction of the ciliary muscles (CNs III)

134
Q

What causes a raised intracranial pressure?

A

an increased pressue in fluid surrounding the brain or an increase in pressure within the brain itself:

brain tumour / head injury / hydrocephalus / meningitis / stroke

135
Q

There are 3 main compenents that contribut to the intracranial volume, what are they?

A

brain, blood and CSF

136
Q

why can’t the cranial cavity cope with an increase in intracranial volume?

A

it is an eclosed space that is not flexible or elastic

137
Q

what proportion of pateints with a raised ICP will report with visual problems?

A

65-75%

138
Q

What are some common visiual problems people with a raised ICP report with?

A

transient blurred vision

double vision - diplopia

loss of vision

papilloedema

pupillary changes

139
Q

What is the optic nerve (CN II) covered by?

A

meninges:

dura matter

arachnoid matter

Pia matter

140
Q

what is the space between the arachnoid and pia called?

What is this space filled with?

A

sub- arachnoid space

filled with cerebrospinal fluid (CSF)

141
Q

What are the meninges?

A

protective coverings of the brain and spinal cord

142
Q

how many layers of dura mater are there and what do they enclose?

A

2 layers that enclose the dural venous sinuses

143
Q

which is nerve provides the sensory supply to the dura mater?

A

CN V - trigeminal nerve

144
Q

where is the subarachnoid space found?

A

between arachnoid mater and pia mater:

completely surrounds both the brain and the spinal cord

(continuous)

145
Q

what is the function of the subarachnoid space?

A

contains CSF which cushions and protects

146
Q

how much CSF is produced / day?

A

400-500 ml/day

147
Q

Where is the CSF produced?

A

in the choroid plexus of the ventricles

148
Q

Where is the CSF reabsorbed?

A

into the dural venous sinus via the arachnoid granulations

149
Q

Where can CSF be sampled?

A

via lumbar puncture at L3/4 or L4/5 IV disc levels

150
Q

What appearance should CSF have?

A

should be clear

151
Q

Label the following diagram of the brain ventricles and other important structures:

A
  1. The 3rd ventricle
  2. Left lateral ventricle
  3. Right lateral ventricle
  4. The subarachnoid space
  5. Central canal
  6. The 4th ventricle
  7. The cerebral aquaduct
  8. th pituitary gland
  9. The optic chiasm
  10. The superior sagittal sinus
152
Q

Outline the circularion of CSF :

A
  1. secreted by the choroid plexus (modified pia locared in the lateral and 3rd ventricles)
  2. through the cerenral aquaduct into the 4th ventricle
  3. into the subarachnoid space( and some into the the central canal)
  4. reabsorbed from the subarachnoid space via the arachnoid granulations
  5. Into the dural venous sinuses
153
Q

where would a raised ICP be transmitted?

A

along the subarachnoid space in the optic nerve sheath

154
Q

How does a raised ICP affect the optic nerve, central artery and vein of the retina?

A

compresses them - can lead to bulging or swollen optic discs (papilloedema)

155
Q

what type of damage is CN III (oculomotor nerve) susceptible in a raised ICP?

A

compression / tentortial herniation

156
Q

What can damge to CN III result in?

A

paralysis of somatic motor innervation

paralysis of parasympathetic innervation of the sphincter of the pupil

157
Q

if you ask someone to look straight ahead and they do this, which nerve is damaged?

A

Oculomotor nerve - supples all extraocular muscles apart from lateral rectus and superior oblique

158
Q

How can the trochlear nerve be damaged by a raised ICP?

A

stretching / compression

159
Q

what can damage to the trochlear nerve (CN IV) result in?

A

paralysis of the superior oblique muscle

inferior oblique muscle is unopposed so eye can not move inferomedially

160
Q

If you ask a patient to gaze to the right and they look like this what nerve is damaged?

What visual symptom might this pateint experience?

A

damage to the trochlear nerve ( CN IV)

diplopia when looking down

161
Q

how can a raised ICP damage the abducent nerve ( CN VI)?

A

stretching

162
Q

what can damage to the the abducent nerve cause? How will this clinically present?

A

paralysis of the lateral rectus muscle

eye cannot move laterally in the horizontal plane

medial deviation of the eye

Ophthalmology (9 decks)

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