2: Anatomy - orbit and eye Flashcards
(105 cards)
1
Q
What is the bony orbit?
A
Hole in the skull which the eyeball (globe) sits in
2
Q
Which cranial bones make up the bony orbit?
A
Frontal bone
Maxilla
Zygoma
Sphenoid bone
Ethmoid bone
Lacrimal (a new one)
3
Q
What are two important features of the frontal bone related to the bony orbit?
A
Orbital plate - the part of the frontal bone on the inside of the orbit
Supraorbital notch - or foramen, if it’s closed
4
Q
What is an important feature of the maxilla in relation to the bony orbit?
A
Infraorbital foramen
5
Q
Which important structures travel through the supraorbital and infraorbital notches?
A
Neurovascular bundles
6
Q
What is an important feature of the sphenoid bone which transmits the optic nerve and blood vessels of the bony orbit?
Which feature of the sphenoid bone transmits other nerves and is found close to this structure?
A
Optic canal
Superior orbital fissure
7
Q
What space is found inferior and lateral to the optic canal?
Which bone are it and the optic canal found in?
A
Superior orbital fissure
Sphenoid bone
8
Q
The edges of the bony orbit are called ___.
A
margins
9
Q
What are the superior, inferior, medial and lateral margins of the bony orbit collectively called?
A
Orbital rim
10
Q
Where is the apex of the bony orbit found?
A
Optic canal
11
Q
The apex of the bony orbit is slightly (medial / lateral).
A
medial
or nasal
12
Q
The superior, inferior, medial and lateral margins are collectively known as the ___ ___.
A
orbital rim
13
Q
How does the orbital rim protect the eye?
A
Anything larger in diameter than the orbital rim cannot make contact with the eye
So it protects the eye from direct trauma
14
Q
Which is more anterior:
superior orbital margin
inferior orbital margin?
A
superior orbital margin
where your eyebrows sit
15
Q
The orbital rim is fairly (thick / thin).
A
thin
16
Q
What name is given to fractures of the medial and inferior orbital margins?
A
Orbital blowout fracture
17
Q
What can be compromised by an orbital blowout fracture?
A
Inferior neurovascular bundle
e.g infraorbital nerve, a branch of CN V2 (maxillary division of trigeminal nerve)
causing a sensory deficit to maxillary skin
18
Q
What would happen if CN V2 was damaged by an orbital blowout fracture?
A
Loss of sensation to maxillary region of skin
19
Q
Which structure holds the eye in place and can be damaged by a zygoma fracture?
A
Suspensory ligament
Eye drops towards floor of orbit, causing diplopia (double vision)
20
Q
Which circular muscle surrounds the eye and is responsible for closing the eyelids?
A
Orbicularis oculi
21
Q
What is the function of the orbicularis oculi muscle?
A
Closes the eyelids
22
Q
What are the two parts of the orbicularis oculi muscle?
A
Orbital (outer)
Palpebral (inner)
23
Q
Which sheet of fascia connects the orbital rim to the eyelids?
A
Orbital septum
24
Q
Which bits of fascia hold the shape of the upper and lower eyelids?
A
Superior tarsus and inferior tarsus
25
The tendon of **which muscle** attaches to the superior tarsus and helps to lift the superior eyelid?
**Levator palpebrae superioris**
26
Which muscles are responsible for
a) opening the superior eyelid
b) closing both eyelids?
**a) Levator palpebrae superioris**
**b) Orbicularis oculi**
27
Which ligaments hold the shape of the eye?
**Medial palpebral ligament**
**Lateral palpebral ligament**
28
Name the following structures:
a) Hold the shape of the **superior** and **inferior** eyelids (2)
b) Hold the general shape of the eye (2)
c) Extends as a sheet from the orbital rim to the eyelids (1)
d) Attaches to the superior eyelid and helps open it (1)
e) Closes both eyelids
**a) Superior** and **inferior tarsus**
**b) Medial** and **lateral palpebral ligaments**
**c) Orbital septum**
**d)** Tendon of **levator palpebrae superioris**
**e) Orbicularis oculi**
29
Name the important connective tissue structures of the eyelids.
**Orbital septum**
**Superior** and **inferior tarsus**
Tendon of **levator palpebrae superioris**
**Medial** and **lateral palpebral ligaments**
30
Which glands secrete lipids into the eye?
**Tarsal glands**
31
What is the purpose of the fluid secreted by the **tarsal glands**?
**Stops the eyelids from sticking together**
32
Which structures cover the
a) **iris** and **pupil**
b) **sclera**?
**a) Cornea**
**b) Conjunctiva**
33
Which structures are **covered** by the:
a) conjunctiva
b) cornea?
**a)** Sclera
**b)** Iris and pupil
34
The **lacrimal gland** is found in the **superior** and **lateral** part of the eye.
Where does lacrimal fluid **drain**?
Where exactly is it found?
**Inferior lacrimal papilla**
**Inferior** and **medial part of the eye**
35
Through which structure in the inferior lacrimal papilla does lacrimal fluid drain?
**Lacrimal punctum**
36
Lacrimal fluid is secreted from the ___ \_\_\_ and drains through the ___ \_\_\_ ___ via a small \_\_\_.
**lacrimal gland**
**inferior lacrimal papilla**
**punctum**
37
Which cranial nerve supplies the lacrimal glands?
Is it **sympathetic** or **parasympathetic**?
**CN VII** (Facial nerve)
## Footnote
**Parasympathetic**
38
Once lacrimal fluid has drained through the punctum of the inferior lacrimal papillae, which structures does it pass through?
**Canaliculi**
**Lacrimal sac**
**Nasolacrimal duct...**
39
The lacrimal gland is supplied by **(sympathetic / parasympathetic)** fibres of CN \_\_\_.
**parasympathetic fibres** of **CN VII (Facial nerve)**
40
What is the rough diameter of the eyeball in cm?
**2.5 cm**
41
Which structure is found in the centre of the iris?
**Pupil**
42
What is another name for the eyeball?
**Globe**
43
Name the **three** layers of the eye from **outer** to **inner**.
**Fibrous layer**
**Uvea / vascular layer**
**Retina**
44
The eye is made up fibrous, ___ and retinal layers.
**vascular** (uvea)
45
Which structures are found in the **fibrous** layer of the eye?
**Sclera**
**Cornea**
46
The cornea is responsible which percentage of the eye's refractive power?
**66%**
47
The **uvea** of the eye is highly \_\_\_.
**vascular**
48
Which structure of the **vascular layer** controls the diameter of the pupil?
**Iris**
49
Which structure of the **vascular** layer controls the **iris,** the **shape of the lens** and secretion of **aqueous humour**?
**Ciliary body**
50
Which structures are responsible for
a) **pupil diameter**
b) **secretion of aqueous humour**
c) **shape of lens**
d) **nutrition and gas exchange**?
**a) Iris**
**b) Ciliary body**
**c) Ciliary body**
**d) Choroid**
51
The ___ nourishes the eye.
**choroid**
52
What are three important parts of the retina?
**Optic disc**
**Macula**
**Fovea**
53
Apart from the three layers, the eye is further subdivided into ___ and \_\_\_.
**segments**
**chambers**
54
Which segment of the eye has two **chambers**?
**Anterior segment**
55
The **anterior chamber** of the anterior segment of the eye is the space between the ___ and iris.
**cornea**
56
The posterior chamber of the anterior segment of the eye is the space between the iris and the ___ \_\_\_.
**suspensory ligaments**
57
The anterior segment of the eye contains (aqueous / vitreous) humour.
**aqueous humour**
58
The **posterior** segment of the eye is found behind the \_\_\_.
**lens**
59
The **posterior** segment of the eye contains (**aqueous / vitreous**) humour.
**vitreous humour**
60
What is the junction between the **sclera** and the **cornea** called?
Limbus
61
Which angle is important in **glaucoma** and is found in the **anterior chamber**?
**Iridocorneal angle**
62
What produces **aqueous fluid** in the posterior chamber?
**Ciliary body**
Remember this is part of the **uvea** (vascular layer of the eye)
63
**Aqueous fluid** is produced by the ___ \_\_\_ and then moves from **posterior** to **anterior** before draining where?
**ciliary body**
**iridocorneal angle**
64
Aqueous fluid drains into what at the iridocorneal angle?
**Scleral venous sinus**
65
Aqueous fluid secretion and drainage affects what property of the eye?
**Intra-ocular pressure**
66
Through which neck blood vessel does oxygenated blood reach the **ophthalmic artery**?
Which space within the cranial cavity does this blood vessel run in?
**Internal carotid artery**
**Cavernous sinus**
67
What is the important **end artery** supplying the back of the eye?
**Central artery of the retina**
68
The **central artery of the retina** passes **within** which important structure to supply the back of the eye?
**Optic nerve** (CN II)
69
What is the **only vein to drain the retina**?
**Central vein of the retina**
70
Which veins drain the bony orbit?
**Superior** and **inferior ophthalmic veins**
Which drain into the cavernous sinus eventually
71
What is the **danger triangle of the face**?
**Area comprising upper lip and nose**
Facial veins here have NO VALVES, so if bacteria get into them they can travel through the veins of the bony orbit to the cavernous sinus and cause infections like meningitis
So don't pop spots here
72
With regards to the retina, what is the **entire** **posterior area** which absorbs light?
**Fundus**
73
What are the three important structures found in the **fundus** of the retina?
**Optic disc**
**Macula**
**Fovea**
74
Which part of the retina is a **blind spot**?
Why?
**Optic disc**
Where CN II forms and blood vessels enter and exit
75
The macula has the greatest number of **(rods / cones)**.
**cones**
Responsible for acute colour vision
76
What area is found at the centre of the macula and is capable of the most acute vision?
Why?
**Fovea**
Has the greatest density of cones
77
Describe the **layers** of the retina from **posterior** **to anterior**.
Posterior to anterior:
**Photoreceptors** (which absorb light)
**Ganglion cells**
**Axons** of ganglion cells
Then **blood vessels**
(Weird because you'd think photoreceptors would be closest to the light)
78
Are there photoreceptors in the optic disc?
**No, optic disc is where CN II and blood vessels are**
**"Blind spot"**
79
Which retinal vessels have to be occluded to cause
a) **isolated areas of visual field loss**
b) **total visual field loss**?
**a)** Retinal artery / vein
**b)** Central artery / vein of the retina
80
Which terms describe vision
a) towards the nose
b) away from the nose?
**a) Nasal**
**b) Temporal**
81
Light from objects in the **right** visual field are processed by the **(right / left)** visual cortex.
**Right visual field \> Left visual cortex**
82
Light from objects in the **left visual field** is processed by the **(left / right)** visual cortex.
**Left visual field \> Right visual cortex**
83
\*\* In general, **light coming FROM the left is processed on the right side** and vice versa \*\*
Same for up and down
84
There are **seven** extra-ocular muscles. What are they called?
**Rectus** **muscles** - superior, inferior, medial and lateral
**Oblique** - superior and inferior
**Levator palpebrae superioris**
85
What does the **levator palpebrae superioris** do?
**Lifts upper eyelid**
86
What is the origin of the **rectus** muscles?
**Common tendinous ring**
87
What is the insertion of all the extraocular muscles apart from levator palpebrae superioris?
**Sclera**
88
What is the trick for remembering the innervation of the **extraocular muscles**?
**LR6 SO4 AO3**
LATERAL RECTUS - CN VI - ABDUCENT NERVE
SUPERIOR OBLIQUE - CN IV - TROCHLEAR NERVE
ALL OTHERS - CN III - OCULOMOTOR NERVE
89
**LR\_ SO\_ AO\_**
**LR6 SO4 AO3**
90
**\_\_6 \_\_4 \_\_3**
**LR6 SO4 AO3**
91
Which cranial nerves supply
a) medial rectus
b) lateral rectus
c) inferior oblique
d) orbicularis oculi
e) superior oblique
**a)** CN III
**b)** CN VI
**c)** CN III
**d)** CN VII
**e)** CN IV
LR6 SO4 AO3
92
What movements can the eye make on the **vertical axis**?
**Abduction** (temporally)
**Adduction** (nasally)
93
What movements can the eye make on the **transverse axis**?
**Elevation**
**Depression**
94
What movements can the eye make on the **AP axis**?
**Intorsion** (upper eye twists towards nose)
**Extorsion** (upper eye twists towards temple)
95
The **optic disc** is \_\_\_.
The **macula** is \_\_\_.
(nasal , temporal)
**Optic disc** is NASAL
**Macula** is TEMPORAL
96
Why is the **axis** of the **orbit** different from the optical axis (i.e the way the eyeballs face)?
**Apex of orbit** (marked by optic canal) is slightly **nasal (medial)**
97
What is the action of the **lateral rectus**?
**ABDUCTS** eyeball
98
What muscle needs to **ABDUCT** the eyeball to test the action of two other muscles?
What muscles are these?
**Lateral rectus**
Superior and inferior rectus
99
What is the innervation of lateral rectus?
**CN VI** (Abducent nerve)
Remember **LR6**
100
What is innervation of
a) superior rectus
b) inferior rectus?
What actions do they have when the eyeball is **ABDUCTED** by lateral rectus?
Both innervated by **CN III (Oculomotor nerve)**
**a) Elevates eyeball**
**b) Depresses eyeball**
WHEN ABDUCTED BY LATERAL RECTUS
101
Which muscle's action is required to test **superior** and **inferior rectus**?
**Lateral rectus** (abduction)
102
What is the action of the **medial rectus** muscle?
Which nerve innervates it?
**ADDUCTION** of the eyeball
CN III (Oculomotor nerve)
103
Which muscle's action is required to test the **superior** and **inferior oblique** muscles?
**Medial rectus** (adduction)
104
Which nerves innervate
a) superior oblique
b) inferior oblique?
What actions do these muscles have when the eyeball is **adducted** by medial rectus?
**a) CN IV** (Trochlear nerve)
**b) CN III** (Oculomotor nerve)
**Superior oblique** DEPRESSES **the eyeball**
**Inferior oblique** ELEVATES **the eyeball**
The opposite of what you learned before, for the craic
105
With the eyes in the **central position**, which muscles act **synergistically** to
a) elevate
b) depress the eyes?
**a) Inferior rectus** and **Superior oblique**
**b) Superior rectus** and **Inferior oblique**
