Orbital (Lect) Flashcards
(81 cards)
1
Q
What 7 bones contribute to the walls of the orbit?
A
- Maxilla
- Zygomatic
- Frontal
- Ethmoid
- Lacrimal
- Sphenoid
- Palatine
2
Q
Bones in Roof of the orbit
A
- Frontal (most)
2. Lesser wing of Sphenoid
3
Q
Bones of Lateral Wall of Orbit
A
- Zygomatic Bone
2. Greater Wing of Sphenoid
4
Q
Bones of Medial Wall of Orbit
A
- Frontal
- Lacrimal
- Ethmoid
- Sphenoid
- Palatine
5
Q
Bones of Floor of the the Orbit
A
- Maxilla - orbital surface
2. Palatine Bone
6
Q
Spaces outside of orbit:
- Superior
- Inferior
- Medial
- Lateral
A
Superior:
- Anterior Cranial Fossa
Inferior:
- Maxillary Sinus
Medial:
- Ethmoid Air Cells
Lateral:
- Temporal Fossa
7
Q
What do the 4 extrinsic mm. of the eye insert into?
A
Common Tendinous Ring
8
Q
What is located in the superior group of orbit neurovasculature?
A
- Lacrimal and Frontal Branches of Opthalmic n. (V1)
- CN IV
- Superior Opthalmic V.
9
Q
What is located in the middle group of orbit neurovasculature?
A
- CN II
- Opthalmic A.
- Superior Branch of CN III
- Inferior Branch of CN III
- Nasociliary Branch of Opthalmic n. (V1)
- CN VI
10
Q
What is located in the inferior group of orbit neurovasculature?
A
- Inferior Opthalmic v.
11
Q
What nerve gives parasympathetic innervation to the eye?
A
CN III
12
Q
Where do PREganglionics destined for the eye synapse with POSTganglionic cell bodies?
A
Cilliary Ganglion
13
Q
Where is the ciliary ganglion found?
A
In the orbit
14
Q
How to POSTganglionics get to the structures that they innervate?
A
Hitchhike on SHORT CILIARY NN. (of V1)
15
Q
What smooth muscles are controlled by parasympathetic innervation in the eye?
A
- Constrictor Pupillae
2. Ciliary muscles
16
Q
What are the signs of Sympathetic Loss in the ocular region?
A
- Anhydrosis (lack of sweating)
- Miosis (contricted pupil)
- Ptosis (droopy eyelid)
- Enopthalmos (posterior displacement of eyeball in orbit)
17
Q
What are the signs of parasympathetic loss in the occular region?
A
- Loss of Accommodation (can’t focus the eye, CN III)
- Mydriasis (dilated pupil, CN III)
- Loss of Lacrimation (lack of tearing, CN VII)
18
Q
What is the periostium lining of the orbit called?
- continuous with?
A
Periorbita - continuous with periostium of:
- Infratemporal Fossa
- Middle Cranial Fossa
19
Q
Describe the shape of the rectus muscles?
A
- Superior, Inferior, Lateral, and Medial Rectus muscles form a cone of muscle with the base forming on the sclera and the posterior apex forming at the tendinous ring
20
Q
What makes up the majority of the tissue found within and around the musclular cone?
- purpose?
A
- Adipose Tissue
- Prevents the Rectus mm. and other extrinsic mm. from pulling the eyeball posteriorly
21
Q
What is the suspensory ligament of the eye?
- what does it do?
A
- Suspends the Globe in the orbit to oppose gravity
**Kind of cradles the bottom of the eye
22
Q
What connective tissue backbone is found in the upper and lower eyelids?
A
- Superior and Inferior Tarsal plates
23
Q
Secretions of what gland lubricates the conjunctival sac?
A
- Lacrimal Gland
24
Q
What muscle attaches to the posterior aspect of the superior tarsal plate?
A
- Levator Palpebrae Superioris
25
What muscle is embedded in levator palpebrae superioris?
- Function
- Significance
Superior Tarsal mm.
- Maintains and Open Palpebral Fissure
- one of 3 named smooth muscles in orbit outside of the globe (avascular)
26
What type of innervation controls the inferior and superior tarsal mm.?
- SYMPATHETIC
27
What 6 muscles are responsible for moving the globe?
Rectus mm.
1. Superior Rectus
2. Medial Rectus
3. Inferior Rectus
4. Lateral Rectus
Oblique mm.
1. Inferior Oblique
2. Superior Oblique
28
What muscle raises the upper eyelid?
- Levator Palebrae Superioris
29
What does the Frontal n. (V1) end as?
- Supratrochlear n.
30
What branch of V1 travels laterally after exiting the supraorbital fissure superior to the tendinous ring?
- Lacrimal n.
31
What nerve branches into the anterior and posterior ethmoidal nn.?
- where?
- Nasociliary n.
| - Branches IN the orbit then branches penetrate the ethmoid
32
What artery runs with the nasociliary n.?
Opthalmic a.
33
What are the only two extrinsic eye muscles not innervated by CN III?
Superior Oblique
| Lateral Rectus
34
What 2 nerves always form a connection with the cilliary ganglion?
- 3rd variable connection?
* *Fiber Types
1. Parasympathetic Root - PREganglionic Parasympathetic (GVE) fibers from CN III
2. Sensory Root - GSA via Nasociliary n. (V1)
3. Sympathetic Root - POSTganglionic Sympathetic (GVE) via opthalmic a.
35
What type of sympathetic fibers are carried by the opthalmic artery?
- POSTganglionic fibers from INTERNAL CAROTID Plexus
36
Besides fibers jumping form the opthalmic a., how else can sympathetics get to the eye globe?
Nasociliary n. --> Long Ciliary N.
37
What nerves do the lacrimal and opthalmic aa. run with?
Lacrimal a. ---> Lacrimal n.
| Opthalmic a. ---> Nasociliary n.
38
What n. runs with opthalmic a. BEFORE entering the orbit?
| - after?
BEFORE:
Optic n. (CN II)
After:
Nasociliary n. (V1)
39
What artery branches to give rise to the zygomatic artery?
- Lacrimal a.
40
What branch of the opthalmic a. penetrates the optic n.?
Central Retinal a.
41
What does the superior opthalmic vein drain into after exiting the orbit?
- what hole does it use?
- Superior Orbital fissure to Cavernous sinus
42
What does the inferior opthalmic vein drain into after exiting the orbit?
- What hole does is use?
- Inferior orbtial fissure to Pterygoid Plexus or cavernous sinus
43
What 4 muscles have multiaxis actions in the orbit?
- Superior and Inferior Rectus
| - Inferior and Superior Oblique
44
What is unique about the testing of the eye muscles with multiaxis functionality?
- To test them you ask the patient to move the eye in a direction OPPOSITE to AB/ADducting part of the ACTION of the muscle
45
Why must you get the patient to look in the in in the direction opposite to the direction of the abducting or adducting action of the multiaxis muscle you are testing?
- So that you can isolate the movement specific to that muscle
For example, Medial Rectus and Superoir Rectus both adduct but Superior Rectus is the ONLY muscle that can lift the eye to the right and upward so testing requires isolating that movement
46
What bones separate the orbit from the anterior cranial fossa?
1. Frontal (most)
| 2. Lesser wing of Sphenoid
47
Describe the location of the Periorbita
- Periorbita = Periosteal continuation into the orbit
| - Acts as a fibrous sac surrounding everything
48
Describe the location of the Bulbar Sheath
- Located around the eye from the optic n. to the limbus
49
What is the muscular fascia of the eye?
?????
50
What is the orbital septum?
- Fascial Layer in each eye that attaches the tarsal plates to the bony anterior margin of the orbits
51
The fibers of what muscle pierces the superior orbital septum?
- Levator Palpebrae Superioris
52
What do the medial and lateral palpebral ligaments do?
| - where do they attach?
Attach the Orbital Septa and Tarsal Plates to bony stuctures.
- Lateral: Zygomatic Bone
- Medial: Maxilla
53
what part of the frontal bone overlies the orbit?
Orbital Plate
54
What is the most superior n. to enter through the orbital fissure?
Trochlear n.
55
What are the 2 superficial branches of the opthalmic n. (V1)?
- Deep Branch
Superficial:
- Frontal n.
- Lacrimal n.
Deep:
-Nasociliary Branch
56
What muscle does the frontal n. ride on?
- On the surface of Levator Palpebrae Superioris
57
What nerves does the frontal n. divide into?
- Supratrochlear n.
| - Supraorbital n.
58
What is the function of the supratrochlear and supraorbital nn.?
Cutaneous innervation to:
| - Skin of Scalp and Skin of forhead
59
What muscles does the lacrimal n. ride to get to its gland?
| - What other n. is embedded in this muscle
- Lateral Rectus
| - Abducens n. is often embedded in the medial surface
60
Describe the course of the nasociliary n. after entering the orbit.
- n. and m.
- m. and m.
Medially:
1. Superior to Optic n., Inferior to Superior Rectus
Laterally:
2. Superior to Medial Rectus, Inferior to Superior Oblique
61
What two muscles does the oculomotor n. enter between?
Between two heads of the lateral rectus muscle
62
What muscle does the oculomotor n. pass through to the get into the orbit?
Between the two heads of lateral Rectus
63
Which branch of oculomotor carries the preganglionic parasympathetic fibers?
- Where do these synapse?
- Lower division of CN III (oculomotor)
| - Synapse in Ciliary Ganglia
64
Between what two structures can the ciliary ganglia be found?
Optic N. (CN II) - inferior
| Superior Rectus m. - Superior
65
What nerve provides the sensory root to the ciliary ganglion?
- Nasociliary n.
66
What transmits sympathetic and sensory fibers to the globe?
Short Ciliary nn.
***These also transmit Post-ganglionic Parasympathetics
67
What is the major different between the origin of blood supply of the eye and the infratemporal FOSSA?
- Eye = Internal Carotid
| - ITF = External Carotid
68
What artery supplies blood to the retina?
Central Artery of the Retina
69
What would be the angle between your eyes if they pointed along the same angle as the orbits?
- There would be 90º
70
What are the 3 avascular smooth muscles of the orbit?
1. Orbitalis
2. Superior Tarsal m.
3. Inferior Tarsal m.
71
What muscle spans the inferior orbital fissure?
| - Purpose?
- Orbitalis m.
| - Plugs IOFi in order to raise intraocular pressure
72
T or F: the orbitalis m. is under parasympathetic tone
FALSE, all 3 avascular smooth mm. of the orbit are under sympathetic tone
73
What is Horner's Syndrome?
Loss of Sympathetic Innervation to the head
74
What are they symptoms of Horner's syndrome?
- Constricted Pupils
- Lack of Sweating
- Droopy Eyelids
- Sunken Eyes
75
Explain what leads to each of the symptoms seen in Horner's.
Constricted Pupils:
- Loss of tone in Dilator Pupillae
Sunken Eyes:
- Loss of tone in Orbitalis
Droopy Eyelids:
- Loss of Tone in Superior and Inferior Tarsal Muscles
Lack of Sweating:
- No nerve supply to sweat glands
76
What nerves give rise to the Supratrochlear and Infratrochlear mm.?
Frontal n. => Supratrochlear
| Nasociliary n. => Infratrochlear
77
What fiber types are found in the long ciliary n.?
GVE - Postganglionic Sympathetics
| GSA
78
In what 2 cases in the head do sympathetic nn. violate the rule that they travel on arteries to reach their target?
1. Long Ciliary n./Nasociliary n.
| 2. Deep Petrosal n.
79
T or F: the parasympathetic process of accommodation is partly under conscious control.
True
80
What does belladona do?
- Blocks Parasympathetic Fibers
| - Loss of Parasympathetic tone means pupils dilate
81
How can intraocular pressure cause vision loss?
- Central Retinal Artery gets compressed
