Orbit And eye Flashcards
1
Q
What does the orbit contain?
A
- eyeballs
- extraocular muscles
- nerves
- BV
- SO MUCH fat
- lacrimal gland
2
Q
What are the orbits
A
A pair of bony cavities
3
Q
What is the shape of the orbit?
A
Pyramidal
Base in front
Apex behind
4
Q
Roof of orbit
A
Orbital plate of the frontal bone
5
Q
Lateral wall of the orbit
A
Formed by the zygomatic bone and the greater wing of the sphenoid
6
Q
Floor of the orbit
A
Formed by the orbital plate of the maxilla, which separates the orbital cavity from the maxillary sinus
7
Q
Medial wall of the orbit
A
Formed by the frontal process of the maxilla, lacrimal bone, orbital plate of the ethmoid, and the body of sphenoid
8
Q
What is the purpose of eyelids?
A
Protect the eye from injury and excessive light
9
Q
Upper eye lid
A
Larger and more mobile than the lower lid
10
Q
Where do both eyelids meet?
A
At the medial and lateral angles
11
Q
The opening between the eyelids and the entrance into the conjunctival sac
A
Palpebral fissure
12
Q
What is the superficial surface of the eyelid covered in?
A
Skin
13
Q
What is the deep surface of the eyelid covered with?
A
mucous membrane called the conjunctiva
14
Q
How are the eyelashes arranged?
A
In double or triple rows at the mucocutaneous junction
15
Q
What kind of glands open into the eyelash follicles?
A
Sebaceous
16
Q
Modified sebaceous glands that open into the margin of the eyelid behind the eyelashes
A
Tarsal glands
17
Q
What do tarsal glands secrete?
A
Oily substance which prevents the overflow of tears
18
Q
Thin mucous membrane that lines the eyelids and is reflected at the superior and inferior cornices onto the anterior surface of the eyeball
A
Conjunctiva
19
Q
What is continuous with the cornea?
A
Epithelium of the conjunctiva
20
Q
Potential space
A
The conjunctiva creates this, which opens at the palpebral fissure
21
Q
What ar the eyelids supported about
A
Fibrous sheet called the orbital septum
22
Q
What is attached to the periosteum at the orbital margins
A
Septum
23
Q
What forms the tarsal plates?
A
The orbital margins thicken to form it
24
Q
What is embedded in the tarsal plate
A
Tarsal glands
25
What consists of a large orbital part and a small palpebral part, which are continuous with each other?
Lacrimal gland
26
Where is the locational gland located
Above the eyeball in the upper lateral and anterior aspect of the orbit
27
How many ducts are in the lacrimal gland?
12
28
Where do the ducts of the lacrimal gland open
Into the lateral part of the superior fornix of the conjunctiva
29
What are the two parts of the lacrimal gland
Large orbital part and a small palpebral part, which are continuous with each other
30
Where is the lacrimal gland located in regard to eyeball
Above the eyeball in the upper lateral and anterior aspect and the orbit
31
The preganglionic parasympathetic innervation of the lacrimal glands
Fibers derived from the lacrimal nucleus of the facial nerve
32
What ganglion do the preganglionic parasympathetic fibers reach for the lacrimal gland?
Pterygopalatine ganglion via the greater petrosal nerve of the pterygoid canal
33
When the postganglionic parasympathetic fibers leave the ganglion, where do they join?
Branches of V2 (zygomatic and sygomaticotermporal nerve)
34
How do the postganglionic fibers reach the lacrimal gland?
Lacrimal nerve
35
What is the sympathetic postganglionic supply from (for the lacrimal apparatus)?
Internal carotid plexus
Synapse in the ganglion, not in the head
36
What do the postganglionic sympathetic fibers o the lacrimal apparatus join?
The deep petrosal nerve, the nerve of the pterygoid canal, the zygomatic nerve, and the lacrimal nerve
37
Where do the tears accumulate?
Lacus lacrimalis (lake of tears)
38
What're do the tears enter after they accumulate in the lacus lacrimalis?
Lacrimal canaliculi through the lacrimal punctum
39
Where does the canaliculi pass?
Medically and open into the lacrimal sac, which lies in the lacrimal groove behind the medial palpebral ligament
40
Nasolacrimal duct
The lacrimal sac is the upper blind end of this
41
Where does the nasolacrimal duct start?
At the lower end of the lacrimal sac
42
Where does the nasolacrimal duct descend?
Downward in a bony canal and opens in the inferior meatus of the nose
43
Where does the optic nerve enter?
Enters the orbit by passing through the optic canal
44
What kind of fibers does the optic nerve contain?
Autonomic/sensory/motor
45
What is the optic nerve really?
A tract
46
What accompanies the optic nerve
Ophthalmic artery
47
What is the optic nerve surrounded by?
Meningeal sheaths of pia mater, arachnoid, and dura mater
48
Where does the optic nerve pieces the sclera?
At a point medial to the posterior pole of the eyeball
49
Where do the nerves fuse with the sclera?
At the point where the nerve pierces the sclera
50
What is contained in the subarachnoid space in the optic nerve?
CSF
51
What happens when there is a rise in pressure within the cranial cavity?
It is transmitted to the back if the eyeball and causes papilledema (due to the CSF in subarachnoid space)
52
What are the main nerves to enter the orbit?
- Ophthalmic division of the trigeminal nerve V1
- oculomotor nerve
- trochlear
- abducens
53
What are the branches of the ophthalmic division of the trigeminal nerve?
- frontal (big, prominent)
- lacrimal (toward lacrimal gland)
- nasociliary (medial direction)
54
What does the frontal nerve branch into?
- supratrochlear
| - supraorbital
55
What do the supratrochlear and the supraorbital supply?
The skin of the forehead and the mucous membrane of the frontal sinus
56
How does the lacrimal nerve run?
Passes forward along the upper border of the lateral rectus muscle (toward lacrimal gland)
57
What is the lacrimal nerve joined by?
A branch of the zygomaticotemporal (parasympathetic) nerve, which later leaves to enter the lacrimal gland
58
Where does the lacrimal gland end?
In the skin of the lateral part of the upper eyelid
59
Where does the oculomotor nerve enter?
The orbit through the lower part of the superior orbital fissure
60
What are the branches of the oculomotor nerve?
Superior branch
| Inferior branch
61
Superior branch of the oculomotor nerve
Supplies the superior rectus and levator palpebrae superioris muscles (open your eyelid)
62
Inferior branch of the oculomotor nerve
Supplies the inferior rectus, the medial rectus, and the inferior oblique muscles
63
What does the nerve to the inferior oblique give off?
A branch to the ciliary ganglion
64
What does the ciliary ganglion Carrie?
Parasympathetic fibers to the sphincter pupillae and the ciliary muscle
65
Where does the trochlear nerve enter orbit?
Via the upper part of the superior orbital fissure
66
What does the trochlear nerve supply?
Superior oblique muscle
67
What is the only nerve from the posterior aspect of the midbrain?
Trochlear nerve
68
Where does the abducens nerve enter?
The orbit through the lower part of the superior orbital fissure
69
What does the abducens nerve supply?
Lateral rectus
70
How does the nasociliary muscle run?
Crosses above the optic nerve, runs forward along the upper margin of the medial rectus muscle, and ends by dividing into anterior ethmoidal nerve and the infratrochlear nerve
71
what are the branches of the nasociliary nerve?
- communicating branch to the ciliary ganglion (sensory)
| - long ciliary nerves
72
Long ciliary nerve
- branch of the nasociliary nerve
- contains sympathetic fibers for the dilator pupillae muscle
- pierce the sclera of eyeball
73
Posterior ethmoidal nerve
Supplies the ethmoidal and sphenoidal air sinuses (right in the center of the head)
74
How does the infratrochlear nerve run?
Passes forward below the pulley of the superior oblique muscle
75
What does the infratrochlear supply?
Medial part of the upper eyelid and the adjacent part of the nose
76
How does the anterior ethmoidal nerve pass?
Through the anterior ethmoidal foramen and enters the anterior cranial fossa. It enters the nasal cavity and emerges on the face as the external nasal branch
77
WHat does the anterior ethmoidal nerve supply?
Mucosa in the nose, when it comes out onto the face as the external nasal branch, it supples the nose as far down as the tip
78
What does the ophthalmic artery branch from?
Internal carotid artery
79
How does the ophthalmic artery enter the orbit?
Through the optic canal with the optic nerve
80
Branches of the ophthalmic artery
- central artery of the retina
- muscular branches
- ciliary arteries
- lacrimal artery
- supratrochlear artery
- supraorbital artery
81
Branches of central artery of the retina
- most important branch of the ophthalmic artery
| - runs within the optic nerve and enters the eyeball at the center of the optic disc
82
Muscular branches of ophthalmic artery
Supply the extraocular muscles
83
Ciliary arteries
- branches of the ophthalmic artery
- divided into the anterior and posterior groups
- anterior enters eyeball near the corneoscleral junction
- posterior enters near optic nerve
84
Lacrimal artery
- branch of the ophthalmic artery
| - lacrimal gland
85
Supratrochlear and supraorbital arteries
- branches of the ophthalmic artery
| - distributed to the skin of the forehead
86
Superior ophthalmic vein
Communicates in front with the facial vein
87
Inferior ophthalmic vein
- branch of the ophthalmic vein
| - communicates through the inferior orbital fissure with the pterygoid venous plexus
88
How do the branches of the ophthalmic veins pass
Backward through the superior orbital fissure and drain into the cavernous sinus
89
Ciliary ganglion
Parasympathetic ganglion about the size of a pinhead
90
Where is the ciliary ganglion located?
Posterior part of the orbit
91
What kind of fibers does the ciliary ganglion receive?
Preganglionic parasympathetic fibers from the oculomoter nerve via the nerve to the inferior oblique
92
How do the postganglionic fibers leave the ciliary ganglion
In the short ciliary nerves, which enter the back of the eyeball and supply the sphincter pupillae and the ciliary muscle
93
Stand alone parasympathetic fibers
Pterygopalatine
94
What is the presynaptic root of the ciliary ganglion?
Oculomoter
95
What innervated the dilator pupillae and the levator palpebrae superioris
Postsynaptic sympathetic nerve fibers
96
The center of the cornea or the center of the pupil is used as the anatomical
Anterior pole
97
What all directions of the movement of the anterior pole as it rotates on any one of the three axes
Horizontal, vertical, sagittal
98
Rotation of the eye upward
Elevation
99
Rotation of the eye downward
Depression
100
Roast action of the eye laterally
Abduction
101
Rotation of the eye medially
Adduction
102
What does the eye use as a marker for rotary movements
Upper rim of the cornea or pupil as the marker
103
How does the eye rotate
Medially or laterally
104
What are the muscles of the eye?
- superior rectus
- inferior rectus
- medial rectus
- lateral rectus
- superior oblique
- inferior oblique
105
What do the superior and inferior recti do?
Inserted on medial side of the vertical axis of the eyeball, they not only raise and depress the cornea, respectively, but they also rotate it medially
106
What must happen for the superior rectus to raise the cornea?
The inferior oblique must also assist
107
Where does the superior oblique muscle pass?
Through the trochlear in the medial part of the orbit
108
Tendon of the superior oblique
Turns backward to insert into the sclera beneath the superior rectus muscle
