Anatomy of the Eye Flashcards
1
Q
what is the orbit?
A
the bony cavity housing the eye
2
Q
how many bones make up the orbit?
A
7
3
Q
what are the bones that make up the orbit?
A
frontal zygomatic maxilla palatine sphenoid ethmoid lacrimal
4
Q
what is the most superior bone in the orbit?
A
frontal
5
Q
what is the lateral bone of the orbit?
A
zygomatic
6
Q
what is the inferior and medial bone in the orbit?
A
maxilla
7
Q
what are the orbital plates?
A
flat areas on the walls of the orbit
8
Q
which bones have orbital plates?
A
ethmoid
frontal
maxilla
9
Q
what is more likely to affect a bone with an orbital plate?
A
a fracture
10
Q
what passes through the optic canal?
A
optic nerve
ophthalmic artery
11
Q
what nerves pass through the superior orbital fissure?
A
CN III
CN IV
CN VI
12
Q
what cranial nerves control the movement of the eye?
A
3 4 and 6
13
Q
where is the optic canal located?
A
the sphenoid bone
14
Q
where is the superior orbital fissure located?
A
the sphenoid bone
15
Q
where is the infraorbital foramen located?
A
the maxilla
16
Q
where is the supraorbital notch located?
A
the frontal bone
17
Q
what shape is the orbit?
A
pyramidal
18
Q
what is another name for the base of the orbit?
A
the orbital rim
19
Q
what is the external layer of the eyelid made of?
A
muscle
20
Q
what is the muscle that makes up the external eyelid?
A
orbicularis oculi
21
Q
what are the two parts of orbicularis oculi?
A
orbital and palpebral parts
22
Q
where is the orbital part of orbicularis oculi found and what does it do?
A
surrounding the orbit
closes eyes tightly
23
Q
where is the palpebral part of orbicularis oculi found and whta does it do?
A
on the eyelid
closes eyes gently
24
Q
what nerve innervates the orbicularis oculi?
A
CN VII
25
what is the deeper layer of the eyelid made of?
fibrous connective tissue
26
what does the orbital septum help with?
preventing spread of infection in the orbit
27
what does LPS stand for?
levator palpebrae superioris
28
what does the lacrimal gland produce?
lacrimal fluid
29
what nerve innervates the lacrimal gland?
CN VII
30
where does lacrimal fluid that has been on the eye draiN?
through the lacrimal puncta into the canaliculi
drains into the inferior meatus of the nasal cavity
31
how many extraocular muscle are there?
seven
32
what are the groups of extraocular muscles?
4 rectus muscles
2 oblique muscles
levator palpebrae superioris
33
where do the rectus muscles run?
straight onto the eyeball from the posterior orbit
34
what are the four rectus muscles?
superior
inferior
medial
lateral
35
what are the two oblique muscles?
superior
| inferior
36
where do the rectus muscles originate?
common tendinous ring
37
where do the rectus muscles insert?
sclera
38
where does the superior oblique originate?
sphenoid bone
39
where does the superior oblique pass before inserting?
through the trochlea
40
where does the inferior oblique originate?
the orbital plate of the maxilla
41
where do the oblique muscles insert?
sclera
42
where does the LPS originate?
lesser wing of sphenoid
43
where does LPS insert?
onto the skin and tarsus of the superior eyelid
44
what is the mnemonic used to remember the innervation of the extraocular muscles?
LR6 SO4 AO3
lateral rectus - CN 6
superior oblique - CN 4
all others - CN 3
45
what is another name for the limbus?
the corneoscleral junction
46
what is the limbus?
where the cornea and sclera meet at the margins of the iris
47
what is the conjunctiva on the eye called?
the bulbar conjunctiva
48
what is the conjunctiva on the surface of the eyelid called?
palpebral conjunctiva
49
what is the area where the conjunctiva is reflected onto the eyelid called?
the conjunctival fornix
50
what covers the iris?
the cornea
51
how does the cornea get its nutrients?
from lacrimal fluid and aqueous fluid
52
how does the lacrimal fluid get oxygen?
from the air in front of the eye
53
what are the three layers of the eye from outer to inner?
fibrous
uvea
retina
54
what are the two parts of the fibrous layer of the eye?
sclera
| cornea
55
what is another name for the uvea?
the vascular layer
56
what are the three parts of the uvea?
iris
ciliary body
choroid
57
what makes up the majority of the uvea?
the choroid
58
what are the two segments of the eye?
anterior
| posterior
59
where is the anterior segment found?
in front of the lens
60
what are the two parts of the anterior segment?
anterior chamber
| posterior chamber
61
where is the anterior chamber?
between the cornea and the iris
62
where is the posterior chamber?
between the iris and the ligaments of the lens
63
where is the posterior segment?
behind the lens
64
what does the posterior segment contain?
vitreous body/humour
65
what is the role of the vitreous humour?
holds the retina in place
| helps support the lens
66
what produces aqueous humour?
ciliary body
67
where does aqueous humour flow?
posterior chamber then through the pupil to the anterior chamber
68
where is the aqueous humour reabsorbed into?
the scleral venous sinus at the iridocorneal angle
69
what is another name for the scleral venous sinus?
canal of Schlemm
70
what makes up the majority of the blood supply to the eye?
the ophthalmic artery
71
what artery is the ophthalmic artery a branch of?
internal carotid
72
how does the internal carotid artery enter the cranial cavity?
via the carotid canal
73
how does the ophthalmic artery enter the orbital cavity?
through the optic canal
74
what are the three features found on the retina?
optic disc
macula
fovea
75
what is the optic disc?
the area of CN II formation
| the only point of entry/exit for vessels
76
what causes a persons "blind spot"?
the lack of photoreceptors on the optic disc
77
what is the macula?
the small, oval shaped area on the retina
78
where on the retina is the greatest density of cones found?
the macula
79
what is the fovea?
the centre of the macula
80
what part of the retina provides the most acute vision?
the fovea
81
what are the three layers of the retina from posterior to anterior?
photoreceptors
ganglion cells
axons of the ganglion cells
82
where do the retinal veins and arteries lie?
anterior to the retina
83
what does complete interruption of the central artery or vein cause?
monocular blindness
84
what three axes does movement of the eyes occur around?
vertical
transverse
anteroposterior (AP)
85
what movements of the eye occur in the vertical axis?
abduction
| adduction
86
what movements of the eye occur in the transverse axis?
elevation
| depression
87
what movements of the eye occur in the anteroposterior axis?
intorsion
| extorsion
88
what nerve innervates the medial rectus?
CN III
89
what nerve innervates the lateral rectus?
CN VI
90
what nerve innervates the superior rectus?
CN III
91
what nerve innervates the inferior rectus?
CN III
92
what nerve innervates the superior oblique?
CN IV
93
what nerve innervates the inferior oblique?
CN III
94
what is the clinical test to assess the function of the medial rectus?
look in
95
what is the clinical test to assess the function of the lateral rectus?
look out
96
what is the clinical test to assess the function of the superior rectus?
look out and up
97
what is the clinical test to assess the function of the inferior rectus?
look out and down
98
what is the clinical test to assess the function of the superior oblique?
look in and down
99
what is the clinical test to assess the function of the inferior oblique?
look in and up
