06c: Orbit Flashcards Preview

Body Structures H&N > 06c: Orbit > Flashcards

Flashcards in 06c: Orbit Deck (68):
1

Eyelids are composed of (X), which are sandwiched by (Y) anteriorly and (Z) posteriorly.

X = small tarsal plates
Y = skin and muscle (orbicularis oculi)
Z = conjunctiva

2

Tarsal glands are located in/on (X) and function to (Y).

X = in tarsal plate
Y = produce fluid that prevents eyelids from sticking together

3

Black eye develops as result of:

Extravasated/accumulated blood into subcutaneous tissue and skin of eyelids

4

T/F: Tears are continuously produced by lacrimal glands.

True

5

Blinking wipes tears in which direction? List the progressive structures into which they drain.

Lateral to medial;

1. Superior and inferior lacrimal puncta
2. Superior and inferior lacrimal canaliculi
3. Lacrimal sac
4. Nasolacrimal duct
5. Inferior nasal meatus

6

What's the explanation for blinking causing increased tear production?

Lacrimal gland divided into orbital/palpebral parts by levator palpebrae superioris tendon; blinking "milks" tears from gland

7

Parasympathetics to lacrimal gland via (X) have which effects?

X = CN 7
Secretomotor to gland and vasodilation

8

Sympathetics to lacrimal gland via (X) have which effects?

X = sympathetic trunk

Vasoconstriction

9

List pathway of pre-ganglionic parasympathetic fibers to lacrimal gland prior to synapse on (X).

X = pterygopalatine ganglion

1. CN 7 (Greater petrosal)
2. Nerve to pterygoid canal

10

List pathway of post-ganglionic parasympathetic fibers to lacrimal gland following synapse on (X).

X = pterygopalatine ganglion

1. Zygomatic nerve
2. Zygomaticotemporal nerve
3. Lacrimal nerve

11

(Pre/post)-ganglionic sympathetics for CN 7 enter skull via (X) and become (Y).

Post;
X = internal carotid plexus
Y = deep petrosal nerve

12

Deep petrosal nerve carries (X) and joins (Y) on its path, just prior to (Z).

X = sympathetics to lacrimal gland
Y = greater petrosal nerve
Z = synapse on pterygopalatine ganglion

13

T/F: Nerve of pterygoid canal carries sympathetics to lacrimal gland.

True - both parasympathetic (greater petrosal) and sympathetic (deep petrosal)

14

Tears spilling over inferior eyelid is indicative of (X) nerve damage. Explain.

X = CN 7

Orbicularis oculi loss of function; abnormal blinking results in excessive lacrimation and abnormal tear drainage.

15

List the muscles involved in moving eyelid. Include the nerve(s) innervating each.

1. Orbicularis oculi (CN VII)
2. Levator palpebrae superioris (CN III)
3. Superior tarsal muscle (sympathetics)

16

Damage to CN 3 causes ptosis, aka (Y), due to loss of innervation of (Z).

Y = drooping eyelid
Z = levator palpebrae superioris

17

Action of superior tarsal muscle.

Elevates eyelid during sympathetic response (ex: fear)

18

Which nerves involved in afferent and efferent pathways for corneal (blink) reflex?

Afferent: CN V (V1) to cornea via short/long ciliary nn
Efferent: CN VII to orbicularis oculi

19

What's the periorbita?

Periosteum of orbit (lining inner surface)

20

List the bones that make up the orbit.

1. Frontal
2. Sphenoid
3. Ethmoid
4. Maxilla
5. Zygomatic
6. Lacrimal
7. Palatine

21

T/F: Temporal bone contributes to orbit.

False

22

T/F: Palatine bone contributes to orbit.

True

23

T/F: Nasal bone contributes to orbit.

False

24

Infraorbital groove is in close proximity with (X) (fissure/foramen). It's a landmark on which bone?

X = inferior orbital fissure

Maxilla

25

Orbital margin is strong, so a "blowout fracture" may typically impact (X) wall of orbit instead. Which spaces affected?

X = medial/inferior

Medial: ethmoidal/sphenoid sinuses
Inferior: maxillary sinus

26

Many structures traveling between interior skull and orbit pass through (X). List the nerves that pass through.

X = cavernous sinus

CN 3, 4, 5 (V1, V2), 6

27

(Axes of orbits/optical axes) diverge at (X) degrees.

Axes of orbits;
X = 45

28

Direction/line of sight is represented by (X) axes, which are parallel to each other.

X = optical

29

Base of orbit is (anterior/posterior) and apex is (anterior/posterior).

Anterior; Posterior

30

(X) of orbit is site of entry for neurovascular structures.

X = apex

31

Most muscles attach (anteriorly/posteriorly) at (base/apex) of orbit.

Posteriorly; apex

32

List the extra-ocular muscles. Star those with nerve supply that differs from the typical (X) nerve.

X = CN III
1. Lev. palpebrae superioris
2. Lateral rectus* (CN 6)
3. Medial rectus
4. Superior rectus
5. Inferior rectus
6. Superior oblique* (CN 4)
7. Inferior oblique

33

The (X) acts as a pulley for which extra-ocular muscle?

X = trochlea

Superior oblique

34

(X) is common tendinous ring in (base/apex) of eye to which (Y) muscles attach.

X = annulus of Zinn
Apex;
Y = the 4 recti muscles

35

Which extra-ocular muscles contribute to intorsion of eye?

Superior rectus and superior oblique

36

Superior oblique originates toward (lateral/medial) part of orbit. Inferior oblique originates toward (lateral/medial) part of orbit.

Both medial

37

T/F: Both extra-ocular oblique muscles insert on posterior part of sclera.

True

38

Which extra-ocular muscles contribute to extorsion of eye?

Inferior rectus and inferior oblique

39

Eyeball in neutral position. Which muscle(s) responsible for elevation of eyeball?

Superior rectus and inferior oblique

40

Eyeball is abducted. Which muscle(s) responsible for elevation of eyeball?

Superior rectus

41

Eyeball is adducted. Which muscle(s) responsible for elevation of eyeball?

Inferior oblique

42

List the actions of eye that are controlled by autonomic NS. Specify if it's parasympathetic/sympathetic.

1. Focusing/accommodation (parasympathetic)
2. Constriction (para) and dilation (symp)
3. Involuntary eyelid elevation (symp)

43

Focusing/accommodation of eye involves innervation from (X) to (smooth/skeletal) muscle within (Y).

X = CN III
Smooth;
Y = ciliary body

44

In focusing/accommodation of eye, the shape of (X) is changing.

X = lens

45

Constriction of pupil involves (para/symp) innervation to (X) muscle.

Parasympathetic;
X = constrictor (sphincter) pupillae

46

Dilation of pupil involves (para/symp) innervation to (X) muscle.

Sympathetic;
X = dilator pupillae

47

T/F: Sympathetic fibers travel through long ciliary nerve, but not short ciliary nerve.

False - but mostly through long ciliary

48

Sphincter pupillae innervated by:

CN III

49

Formal term for max constriction.

Miosis

50

Formal term for max dilation.

Mydriasis

51

Morphine can cause (miosis/mydriasis).

Miosis

52

Migraine can cause (miosis/mydriasis).

Mydriasis

53

Neurovascular structures that pass through superior orbital fissure.

1. CN 3, 4, 5 (V1), 6
2. Superior opthalmic vein

54

Neurovascular structures that pass through supraorbital foramen.

Supraorbital artery and nerve (V1)

55

Neurovascular structures that pass through supratrochlear foramen.

Supratrochlear artery and nerve (V1)

56

Neurovascular structures that pass through anterior and posterior ethmoidal foramina.

Anterior and posterior ethmoidal arteries, veins, and nerves (V1)

57

Neurovascular structures that pass through nasolacrimal canal.

Nasolacrimal duct

58

Neurovascular structures that pass through infraorbital canal.

1. Zygomatic and infraorbital nerves (V2)
2. Infraorbital artery and vein
3. Inferior opthalmic vein

59

Neurovascular structures that pass through inferior orbital fissure.

Infraorbital artery, vein, and nerve (V2)

60

Which bones make up superior wall of orbit?

Frontal (primarily)

61

Superior wall of orbit is also the floor of:

Anterior cranial fossa

62

Which bones make up medial wall of orbit?

Ethmoid and lacrimal bones

63

The paper-thin lamina papyracea separates which spaces?

Orbit and ethmoid air cells

64

Which bones make up lateral wall of orbit?

Zygomatic and greater wing of sphenoid

65

Which bones make up floor of orbit?

Maxilla (and small portion from palatine)

66

Branches of ophthalmic artery correspond to branches of (X) nerve.

X = ophthalmic (V1)

Ethmoidal, supraorbital, suprateochlear, lacrimal

67

Anastomoses between (X) veins may result in spread of infection from eye/nose to cavernous sinus.

X = angular (to facial vein) and ophthalmic veins (to cavernous sinus)

68

List structures passing through optic canal.

1. Sympathetics
2. Optic nerve
3. Ophthalmic artery
4. Central artery of retina (within nerve)