Orbit and the Eye Flashcards
(142 cards)
1
Q
List the components of the bony orbit, in terms of apex, roof, floor and base
A
APEX: optic canal
ROOF: frontal
FLOOR: maxilla
BASE: orbital rim
2
Q
What is the main eye protection from direct blow?
A
Orbital margin/ rim
3
Q
What is the most common presenting complaint in blowout fracture?
A
Pain on upgaze
4
Q
Define what is meant by ‘blowout fracture’
A
Traumatic deformity of orbital floor/ medial wall usually from impact of a blunt object onto the eye socket
5
Q
What is the function of the suspensory ligament of the eye?
A
Thick fascial sling that holds he eye above the floor of the orbit
6
Q
What is the most vulnerable site for orbital trauma? What is the consequence of this?
A
Inferior wall of the orbit
Damage to infraorbital NVB in infraorbital foramen leading to general sensory deficit to the middle third of the face
7
Q
What muscle of facial expression forms the external layer of the orbit? What is it’s nerve supply?
A
Orbicularis oculi
CNVII
8
Q
List the two main parts of the orbicularis oculi muscle and give their function
A
Orbital part - close eye tightly Palpebral part (eyelid only) - blinking
9
Q
What is the function of the orbital septum?
A
Helps prevent spread of infection into the deep tissues
10
Q
The orbital septum is split by…
A
Medial and lateral palpebral ligament
11
Q
What is the function of the tarsal glands?
A
Lipid secretion
12
Q
Which muscle connects the superior tarsal gland to levator palpebrae superficialis?
A
Muller’s muscle
13
Q
The orbital septum is located posterior to…
A
Orbicularis oculi
14
Q
Which muscle(s) control eye opening? What is the nerve supply?
A
LPS with Muller’s muscle
CNIII
15
Q
Which muscle(s) control eye closing? What is the nerve supply?
A
Orbicularis oculi
CNVII
16
Q
The iris of th eye is covered by…
A
The cornea
17
Q
The white sclera of the eye is covered by…
A
Conjunctiva
18
Q
What is the ‘limbus’ of the eye?
A
The corneal limbus is the border of the cornea and the sclera (corneoscleral junction)
19
Q
List the components of the lacrimal gland
A
Lacrimal lake
Inferior lacrimal papilla (swelling)
Inferior lacrimal punctum (opening)
20
Q
What is the function of the conjunctiva of the eye?
A
Lines the lower eyelid and is a barrier to foreign bodies
21
Q
What are the main parts of the conjunctiva of the eye?
A
Palpebral (inner eyelid)
Bulbar (eyeball)
22
Q
How do you distinguish the limbus from the iridocorneal angle?
A
Grey clouding
23
Q
Describe the spacing of fibres in the cornea vs. sclera respectively
A
Straight fibres
Meshwork
24
Q
List the components of the uvea
A
Iris
CIliary body
Choroid
25
What is the 'choroid' of the eye?
Vascular tunic which supplies the outer layers of the retina and contains the ciliary vein
26
The production of lacrimal fluid from the lacrimal gland is controlled by which cranial nerve?
PS CNVII
27
Outline the route taken by lacrimal fluid or tears as it leaves the lacrimal gland
```
Washes over eye -->
Pushed towards medial angle -->
Lacrimal puncta -->
Canalicu -->
Lacrimal sac -->
Nasolacrimal duct -->
Inferior meatus
```
28
What is fibrous outer layer of the eye composed of?
Sclera
| Cornea
29
What is the vascular middle layer of the eye formed from?
Uvea
30
The iris of the uvea of the eye controls...
Pupil diameter
31
The ciliary body of the uvea of the eye controls...
Iris, lens shape, secretion of aqueous humour
32
The chorid of the uvea of the eye controls...
Nutrition and gas exchange
33
What is the photosensitive inner layer of the eye formed from?
Retina
34
List the three layers of the eye in order, from outer to inner
Fibrous outer layer
Vascular middle layer
Photosensitive inner layer
35
The anterior segment of the eye is split into two divisions what are they?
```
Anterior chamber (cornea to iris)
Posterior chamber (suspensory ligament to iris)
```
36
The anterior chamber of the anterior segment of the eye secretes what type of fluid?
Aqueous humour
37
The posterior chamber of the anterior segment of the eye secretes what type of fluid?
Aqueous humour
38
List the two segments of the eye
Anterior (in front of lens)
| Posterior (behind lens)
39
The posterior segment of the eye secretes what type of fluid?
Vitreous humour from the vitreous body
40
The vitreous body within the eye is a common site for what pathology?
Floaters
41
Outline the route taken by aqueous humour from production to drainage
Ciliary body -->
Posterior chamber (nourishes lens)-->
Anterior chamber (nourishes cornea)-->
Dural venous sinus (canal of shlemm)
42
What site of the eye is where aqueous humour is reabsorbed?
Iridocorneal angle
43
Abnormal absorption of aqueous humour results in what type of pathology?
Open or closed angle glaucoma
44
Outline arterial boody supply to the eye
```
Ophthalmic artery (CCA-->ICA-->OA) which branches into ciliary arteries
Branches into nasal and scalp arteries
```
45
Which vessels are 'end arteries' in they eye? What is meant by the term 'end artery'?
Central arteries of retina
| No anastamosis if ischaemia - only blood supply to that area
46
Outline venous drainage of the eye
Little nasal and scalp veins -->
Superior and inferior ophthalmic veins -->
Cavernous sinuses
47
Which foramen allows ophthalmic veins to drain into cavernous sinuses?
Superior orbital fissure
48
What is meant by the 'danger triangle of the face'?
Sinuses connect anteriorly to the valveless facial vein (drains triangle from upper lip to external nose)
Blood can flow bidirectionally, meaning blood from a spot/ cut can drain into the sinuses and cause intracranial infection
49
How is the optic nerve assessed on fundoscopy?
CONTOUR: crisp round edge? blurring?
COLOUR: white centre and pink rim like a rubber ring?
CUP: size (cup: disc ratio)
50
How might the optic nerve appear in the case of increased ICP? Name a pathology that can occur in this case
Swollen, explosion
| Papilloedema
51
How is the optic nerve tested?
```
Visual Acuity (inc. colour)
Visual Fields
Reflexes
Ophthalmoscope
AFRO
```
52
A problem with the nasal retina will affect the nasal/ temporal visual field and vice versa
Temporal
53
A lesion to the optic nerve will cause what visual field defect?
Ipsilateral monocular blindness
54
A lesion to the optic chiasm will cause what visual field defect? Why?
Bitemporal haemanopia
| Nasal retina damaged as they cross at the chiasm causing a bilateral temporal field defect
55
A lesion to the optic tract will cause what visual field defect?
Left or right homonymous haemanopia (vision affected on same side of both eyes)
Described as if you're looking face-on at the patient
56
Which lobe would be affected in a superior quadrantopia?
Temporal lobe
57
Which lobe would be affected in a inferior quadrantopia?
Parietal lobe
58
A lesion to the occipital lobe would result in what visual field defect?
Homonymous haemanopia with macular sparing
59
Which part of the eye is the posterior area where light is focused?
Fundus
60
The optic disc represents the area of...
CNII formation
| Entry/ exit for blood vessels
61
Clinically, the blind spot in a person's vision refers to what?
The absence of photoreceptors in the optic disc
62
Which part of the eye has the greatest density of cones, and therefore, the most acute vision?
Macula (specifically, the fovea at the centre of the macula)
63
List the layers of the retina from anterior to posterior
Photoreceptors
Ganglion cells
Axons of ganglion cells
64
How will complete interruption in blood flow to a retinal artery branch affect vision?
Loss of an area of visual field depending on area of ischaemia
65
How will complete interruption in blood flow to a central retinal artery affect vision?
Monocular blindness in the affected eye
66
How are the quadrants of the eye described?
Upper and lower nasal and temporal
67
Outline the route taken by light as it hits the eye to the retinal layers
```
Tear film -->
Cornea -->
Aqueous humour of anterior chamber -->
Pupil -->
Aqueous humour of posterior chamber -->
Lens -->
Vitreous body and humour -->
Retinal artery/ vein branches -->
GANGLION CELL AXONS -->
GANGLION CELLS -->
PHOTORECEPTORS
```
68
Light hits the retinal layers of the eye from anterior to posterior. True/ False?
False
| From posterior to anterior, ending with photoreceptors
69
Outline the optic pathway from visual field to primary visual cortex
```
Right and left visual field -->
Temporal retina continues ipsilaterally and nasal retina crosses at chiasm -->
Optic nerve -->
Optic chiasm -->
Layer geniculate nucleus -->
Primary visual cortex
```
70
Light from objects in the right visual field processed by left/right primary visual cortex.
Left
71
Light from objects in lower visual field processed by upper/ lower primary visual cortex.
Upper
72
List the seven extraocular muscles, grouping them into types
RECTUS: superior, inferior, medial, lateral
OBLIQUE: superior, inferior
LEVATOR PALPEBRAE SUPERFICIALIS
73
Where do the rectus muscles of the eye originate from?
Common tendinous ring
74
What is the function of LPS, an extraocular eye muscle?
Lifts the upper eyelid
75
Outline the innervation of the extraocular muscles of the eye
```
SOMATIC MOTOR
LR6, SO4, AO3
Lateral rectus: CNVI
Superior oblique: CNIV
All others: CNIII
```
76
List the three axis of the eye, and what movement each control
Vertical: ABD, ADD
Transverse: ELEVATION, DEPRESSION
AP: INTORSION, EXTORSION
77
Which eye movement is controlled by lateral rectus muscle?
Abduction
78
Which eye movement is controlled by superior rectus muscle?
Elevation in abduction
79
Which eye movement is controlled by inferior rectus muscle?
Depression in abduction
80
Which eye movement is controlled by medial rectus muscle?
Adduction
81
Which eye movement is controlled by inferior oblique muscle?
Elevation in adduction
82
Which eye movement is controlled by superior oblique muscle?
Depression in adduction
83
Which two extraocular muscles control pure depression of the eye?
Superior oblique
| Inferior rectus
84
Which two extraocular muscles control pure elevation of the eye?
Superior rectus
| Inferior oblique
85
Sensory innervation of the face is controlled by which CN?
Branches of CNV
86
List the areas of the face in which sensation is controlled by CNV1
Upper eyelid
Cornea
Conjunctiva
Skin of root/bridge/ nose tip
87
List the areas of the face in which sensation is controlled by CNV2
Lower eyelid
Maxilla
Ala of nose
Upper lip
88
List the areas of the face in which sensation is controlled by CNV3
```
Mandible
TMJ
Lower lip
Chin
(except angle of mandible)
```
89
Sensation to the angle of the mandible is controlled by...
C2/3 spinal nerves
90
What term refers to a skin lesion at tip, side or root of the nose? What is a common cause of this?
Hutchinson's sign
| Ophthalmic herpes zoster
91
Which cranial nerve controls the afferent limb of the blink reflex? (Be specific)
Nasociliary branch of CNV1
92
Which cranial nerve controls the efferent limb of the blink reflex?
CNVII
93
Outline the route taken by sympathetic axons to the head and neck, specifically the orbit
Presynaptic axons (cranial nerves) -->
Exit spinal cord at T1-->
Ascend in sympathetic trunk-->
Synapse in superior cervical sympathetic ganglion -->
Postsynaptic sympathetic axons -->
Enter internal and external carotid nerves -->
Pass onto surface of internal and external carotid arteries -->
Organs of head and neck -->
Ophthalmic artery -->
Orbit
94
Outline the route taken by sympathetic axons to organs of the body
Autonomic centres in brain -->
Exit spinal cord at T1-L2 -->
Sympathetic chains on vertebral column -->
Spinal nerves (anterior and posterior ramii) -->
Splanchic nerves to organs
95
Outline the route taken by parasympathetic axons to organs of body
All leave via CNs III, VII, IX, X and sacral spinal nerves (craniosacral outflow)
96
How do parasympathetic axons reach the eye, lacrimal and salivary glands?
Via parasympathetic ganglia in the head
97
How do parasympathetic axons reach the neck, chest and abdomen (as far as the midgut)?
Vagus nerve
98
How do parasympathetic axons reach the hindgut, pelvis and perineum?
Sacral spinal nerves
99
The oculomotor nerve connects with the CNS at...
Junction between midline and pons
100
The oculomotor nerve passes through which anatomical structure?
Cavernous sinus
101
The oculomotor nerve passes through which foramen?
Superior orbital fissure
102
The oculomotor nerve supplies which muscles, and with which modality?
SOMATIC MOTOR: SR, MR, IR, IO, LPS
| PS: ciliary ganglion
103
Describe how the eye would appear in complete CNIII palsy
Eye positioned down and out with ptosis
104
What is the function of the ciliary ganglion?
Autonomic axons to control iris diameter and refractive shape of lens
105
Which fibres are contained by the long ciliary nerve?
Sympathetic
| Somatic sensory
106
Which fibres are contained by the short ciliary nerve?
Sympathetic
| Parasympathetic
107
Which of the long and short ciliary nerves forms the first part of the blink reflex?
Long ciliary nerve (somatic sensory)
108
The short ciliary nerve eventually becomes part of which cranial nerve?
CNV (nasociliary branch)
109
What is the fight or flight response of the eye? Which muscle controls this action? What is it's nerve supply?
Maximal eyelid elevation/ wide eye opening
Levator palpebrae superficialis
CN III
110
What is the function of the pupillary light reflex?
Pupillary dilatation/ constriction adjusting to light entry
111
Dilatation of the pupil is controlled by...
Sympathetics
112
List common situations where the pupil would typically dilate
Dim light
Fight/ flight response
Sickness
Mydriatic pupil
113
Which pupillary fibres control dilatation and constriction of the eye respectively?
Dilatory pupillae fibres
| Syphincter pupillae fibres
114
Constriction of the pupil is controlled by...
Parasympathetics
115
List common situations where the pupil would typically constrict
Bright light
Rest and digest response
Miotic pupil e.g. in Horners
116
Name a pathological cause of a fixed pin point pupil
Opiate drugs
117
Name a pathological causes of a fixed blown pupil
CNIII paralysis
118
List the two main types of pupillary light reflex
Direct (stimulated eye)
| Consensual (non-stimulated eye)
119
The afferent limb of the pupillary light reflex is controlled by which CN?
Ipsilateral optic nerve
120
The efferent limb of the pupillary light reflex is controlled by which CN?
Bilateral oculomotor nerve
121
The two limbs of the pupillary light reflex connect with the CNS at the...
Midbrain
122
Outline the 4 parts of the neurone chain controlling the pupillary light reflex
1, Retinal ganglions are transmittedvia CNII to the optic chiasm and synapse at the pretectal nucleus in the midbrain
2. Synapse at EW nucleus (site of CNIII PS axons and cell bodies exist)
3. Pass via CNIII to the inferior division of the eye and synapse in the ciliary ganglion
4. Pass in short ciliary nerves to the sphincter pupillae muscles
123
What connects the circumference of the lens and the ciliary body?
Suspensory ligament of the lens
124
Describe the structure of the ciliary body
SM like a sphincter around the lens circumference
125
Describe the action of the ciliary body, and thus the change in lens shape in 'far' vision
No parasympathetics, ligament tightens (cilary body relaxes) and lens flattens to focus on object in distance
126
Describe the action of the ciliary body, and thus the change in lens shape in 'near' vision
Parasympathetics cause ligament to relax (cilary body contracts) and lens becomes spherical to focus on near objects
127
Name the two parts of the lens of the eye
Outer: cortex
Inner: nucleus
128
How does the lens change with age?
Becomes less flexible, can't focus as easily
129
What is the function of the accommodation reflex?
Response to 'near' vision - allows the eye to focus on two points
130
Outline the main three components of the accommodation reflex, and the muscle used in each
1. Bilateral pupillary constriction via sphincter pupillae
2. Bilateral convergence of both eyes to midline via medial rectus
3. Bilateral relaxation of lens via ciliary muscle contraction
131
The three components of the accommodation reflex are innervated by which CN?
CNIII
132
What pH does the lacrimation reflex keep tears at?
7.6
133
What type of tears are involved in corneal cleaning, hydration and nourishment?
Basal tears
134
What type of tears are involved in response to chemical/ mechanical stimuli?
Reflex tears
135
What type of tears are involved in reaction to happy/ sad/ frightened feeling?
Emotional tears
136
Outline the neurone root, supplying innervation to the lacrimal gland
CNVII motor axons to muscles of facial expression -->
Stylomastoid foramen -->
Internal acoustic meatus -->
Chorda tympani, motor to stapedius, PS to submandibular/ sublingual glands -->
Branch of V2 -->
V1 --> Axons to lacrimal gland
137
List the symptoms present in Horner's syndrome
Miosis
Ptosis
Ipsilateral reduced anhydrosis
Increased warmth and redness
138
Outline the anatomy affected in Horner's syndrome
Impaired sympathetic innervation to head and neck due to compression of cervical sympathetic trunk
139
Which muscle is comprised, due to compression of it's sympathetic innervation in Horner's, which leads to ptosis?
Muller's muscle controlling LPS
140
List causes of Horner's syndrome
```
Root of neck trauma
Carotid dissection
IJV engorgement
Deep cervical node metastases
Pancoast tumour at lung apex
```
141
What is the vestibulo-ocular reflex?
Turns eyes in opposite direction to head movement allowing eyes to stabilise gaze on an object
142
What is the oculo-cardiac reflex?
Reflex bradycardia due to tension on extraocular muscles/ pressure on the eye
