Anatomy - Orbit Flashcards Preview

Block 5 Material > Anatomy - Orbit > Flashcards

Flashcards in Anatomy - Orbit Deck (78):
1

What bones form the roof and floor of the orbit?

Floor
-orbital process of maxilla
-palatine bone

Roof
-orbital part of frontal bone

2

What bones form the walls of the orbit?

Medial walls
1. Orbital plate of ethmoid
2. Frontal process of maxilla
3. Lacrimal
4. Sphenoid

Lateral walls
-frontal process of zygomatic bone (ant)
-greater wing of sphenoid (post)

3

The apex of the orbit is at the __

Optic canal in the lesser wing of the sphenoid

4

What separates the floor of the orbit from the lateral wall?

Inferior orbital fissure

5

What houses the lacrimal gland?

Fossa for the lacrimal gland in the orbital part of the frontal bone

6

Fissures and foramina of the orbit

1. Optic canal
2. Superior orbital fissure
3. Inferior orbital fissure
4. Infraorbital groove
5. Ethmoidal foramina

7

The optic canal goes through ___ and allows for passage of ___

Goes through the lesser wing of the sphenoid

Allows for passage of
Optic n. (CN II)
Ophthalmic a.

8

Superior orbital fissure is located ___ and allows for passage of ___

Between the greater and lesser wings of sphenoid

Allows for passage of:
CN III
IV
VI
V1
Ophthalmic v.

9

Inferior orbital fissure is located ___ and allows for passage of ___

At the right angle to the superior orbital fissure
-between greater wing of sphenoid and maxilla

Allows for passage of
CN V2 (maxillary n.)
Infraorbital vessels

10

Travel of the infraorbital groove?
What does it contain?

Begins from inferior orbital fissure
Travels anteriorly
Becomes enclosed in bone
Forms infraorbital canal
Opens below orbital rim as the infraorbital foramen

Contains infraorbital n. and vessels

11

Ethmoidal foramina allows for passage of __

Anterior and posterior ethmoidal nerves and vessels

12

____ humor is irreplaceable and more dense than ___

Vitreous

Aqueous

13

The aqueous humor is located in the (anterior/posterior) chamber of the eye

Anterior
Which is between cornea and iris

14

The posterior chamber is located between ___ and ___

Iris and lens

15

3 layers of the eyeball and what they contain

1. Fibrous
- sclera, cornea
2. Vascular
- choroid, ciliary body, iris
3. Retinal
- optic disc, macula, ocular fundus

16

Tough fibrous layer covering the posterior 80% of the eyeball.

The anterior part is visible as the white of the eye

Sclera

17

Transparent part of the fibrous layer located in the anterior part of the eye.

Cornea

18

The cornea is more ___ than the sclera and projects ___

Convex
Anteriorly

19

Blinking and tears are elicited by touching what? and innervation of what nerve?

Cornea
Ophthalmic n. (V1)

20

The ____ lines most of the sclera and contains a rich capillary bed, with the smallest vessels located next to the ___, which is avascular

Choroid
Retina

21

The ____ connects the choroid with the iris. It is both ___ and ___

Ciliary body
Muscular
Vascular

22

The ___ is a thin contractile diaphragm with a central aperture, the ___, for transmitting ___.

Iris
Pupil
Light

23

Two involuntary muscles control the size of the pupil:
-system
-fibers
-action
-speed

Sphincter pupillae
-parasympathetic
-circular fibers
-constriction
-fast

Dilator pupillae
-sympathetic
-radial fibers
-dilation
-slow

24

The optic part of the retina consists of 2 layers:

1. Neural layer
-light sensitive
-continuation of the CN II

2. Pigmented layer
-attached to choroid
-helps reduce scattering of light through absorption

25

During a retinal detachment, which layer of the retina becomes dislodged?

Neural layer only

26

Where the Optic Nerve (CN II) enters the eyeball, the retina contains the __

Optic disc

27

True or false:
the optic disc has photoreceptors

False

28

The oval-shaped area of acute vision is called the __

Macula

29

The posterior part of the eyeball wig its retina is called the ____.
This is where light is ___

Ocular fundus
Focused

30

Light traveling to the retina passes through the following structures:

Cornea
Anterior chamber
Posterior chamber
Lens
Vitreous humor

31

The anterior chamber is filled with ___, which is produced by ___

Aqueous humor
Ciliary body

32

The posterior chamber is filled with __

Aqueous humor

33

The lens is attached to the ciliary processes by __

The suspensory ligament

34

Explain accommodation

-passive stretching and thinning of the lens brings far objects into focus

-sphincter like contraction of ciliary muscle relaxes the lens, bringing near objects into focus (parasympathetic)

35

Layers of the eyelids, anterior to posterior

1. thin skin with loose CT layer
2. Skeletal muscle fibers
3. Orbital septum
4. Tarsi (dense CT, eyelid "skeleton")
5. Conjunctiva
6. Muscles of superior eyelid

36

Skeletal muscle fibers on the second layer of the eyelids:
Action
Innervation

Palpebral part of orbucularis oculi
-involuntary (orbital part is voluntary)
-gently close eyelid
-innervates by CN VII

37

What is the orbital septum?
Attachments?

-Fibrous membrane
-Continuous with periosteum of the orbital rim and the tarsi
-in the upper eyelid it also attaches to levator palpebrae superioris tendon

38

The superior and inferior tarsi are made of ___. Attachments?

Dense CT

Medially: Maxilla through Medial Palpebral ligament

Laterally: zygomatic bone through lateral Palpebral ligament

39

Tarsal glands produce ___

Oily secretions
Keep eyelids from sticking together
Modified sebaceous glands
Increase viscosity of tears
Decrease evaporation

40

Mucous membrane that lines the eyelids internally and reflects into the sclera superiorly and inferiorly

Conjunctiva

41

The upper and lower pockets formed by the reflections of the conjunctiva onto the sclera are called:

Superior and inferior fornices

42

Muscles of superior eyelid elevation

Levator Palpebrae Superioris
Superior Tarsal Muscle

43

Origin, insertion, and innervation of levator Palpebrae superioris

Posterior part of Orbital roof
Superior tarsus
CN III

44

Origin, insertion, and innervation of superior tarsal muscle

Levator Palpebrae Superioris
Superior Tarsus
Sympathetic postganglionic fibers from the superior cervical ganglion

45

The lacrimal gland is located ___ in the ___ corner of the orbit

Anteriorly
Superolateral

46

Excretory ducts carry the lacrimal fluid to the ___ of the conjunctiva

Superior fornix

47

Lacrimal fluid that accumulates in the medial corner of the eye is drained via __

Superior and inferior lacrimal canaliculi

48

The openings of the canaliculi are the ___, located on the ___ surface of the eyelid

Puncta
Posteromedial

49

Innervation of the lacrimal gland

Production of fluid = parasympathetic through CN VII

sympathetic fibers re vasoconstrictive

50

All recti muscles originate from the __ and insert on the __ part of the eyeball

Common tendinous ring around the Optic Nerve (annulus of Zinn)

Anterior

51

Oblique muscles originate from the ___ and attach to the __ part of the eyeball

Orbital walls
Posterior

52

Actions and innervation of:
Lateral rectus

Abduction

CN VI (abducens)

53

Actions and innervation of:
Medial rectus

Adduction
CN III

54

Actions and innervation of:
Superior rectus

Elevation
Slight adduction
CN III

55

Actions and innervation of:
Inferior rectus

Depression
Slight adduction
CN III

56

Actions and innervation of:
Superior oblique

When the eye is abducted:
Abduction and intortion

When the eye is adducted:
Depression

CN IV

57

Origin and insertion of superior oblique

Sphenoid
Goes to trochlea (pulley) and bends to insert on the superior and posterior eyeball

58

Actions and innervation of:
Inferior oblique

When the eye is abducted:
Abduction and extortion

When the eye is adducted:
Elevation

CN III

59

The only extraocular muscle that originates from the anterior part of the orbit (near the lacrimal fossa) is the __

Inferior oblique

60

The ___ is a large sensory nerve partially ensheathed with the cranial meninges

Optic N. (CN II)

61

The optic n. passes into the orbit via the ___ and collects sensory info from the ___. It projects to the ___ geniculate nucleus of the ___

Optic canal
Retina
Lateral
Thalamus

62

The oculomotor n. (CN III) nuclei are in the ___. The nerve exits the brain between the __ and the ___. It passes into the orbit via the ____.

Midbrain
Midbrain and pons
Superior orbital fissure

63

The superior branch of CN III innervates the __ and ___

Levator Palpebrae Superioris
Superior Rectus

64

The inferior branch of CN III innervates the ___, ____, and ____.

Medial rectus
Inferior rectus
Inferior oblique

65

The _____ gives off a branch carrying preganglionic parasympathetic fibers to the ___ ganglion, which continue as ____ nerves to the sphincter pupillae muscle

Inferior branch of CN III
ciliary
Short ciliary

66

The nucleus of CN IV is located in the ___. CN IV enters the orbit via the ___. It innervates the __

Midbrain
Superior orbital fissure
Superior oblique

67

The nucleus of CN VI is in the ___. It enters the orbit through the ___ and innervates the ___

Pons
Superior orbital fissure
Lateral rectus

68

CN V1 is pure ___. It divides into what 3 nerves that pass through what opening into the orbit?

Sensory
Superior orbital fissure
1. Nasociliary
2. Lacrimal
3. Frontal

69

Which branch off of V1 is typically first? What does it supply?

Nasociliary n.
Ciliary ganglion, eyeball, medial eyelids, nose, anterior cranial fossa

70

What structures does the lacrimal n. supply? Frontal n.?

Lacrimal:
Lacrimal gland
Conjunctiva
Lateral part of upper eyelid

Frontal:
Eyelids
Conjunctiva
Forehead
Scalp

71

What artery supplies most of the orbit? It follows the ___ n. to enter the orbit through the ___

Ophthalmic
Optic
Optic canal

72

As the ophthalmic a. is passing along the lateral side of the optic n. it gives off the ___, which supplies the ___

Lacrimal a.
Lacrimal gland

73

Position of the ophthalmic a. relative to the optic n.

Inferolateral but
Upon entering the orbit it crosses superior and medial

74

Branches of the ophthalmic a.

1. Lacrimal
2. Central retinal
3. Posterior ciliary (6 short and 2 long)
4. Muscular branches (anterior ciliary)
5. Supraorbital
6. Ethmoidal
7. Supratrochlear

75

The floor of the orbit also receives blood supply from the ___, which passes into the orbit via the ___ and is a branch of the ___

Infraorbital a.
Infraorbital foramen
ECA

76

Venous drainage of the orbit is through the ___ and the ___, which pass through the ___ and enter the __ sinus.

Superior and inferior ophthalmic veins
Superior orbital fissure
Cavernous

77

The superior ophthalmic v. is formed by the joining of the ___ and the ___.

Supraorbital v.
Angular v.

78

____ veins from the vascular layer of the eyeball drain into the inferior ophthalmic v.

Vortical