THE ORBIT

Question 1

What supports and provide protection to the orbital soft tissues?

Answer 1

The Bony Orbit

Question 2

What makes up the bony orbit?

Answer 2

The roof, lateral wall, floor and medial wall

Question 3

What bones make up the 4 walls

Answer 3

Sphenoid, Frontal, Ethmoid, Maxillary, Zygomatic, Palatine, Lacrimal

Question 4

Which bones are common to both orbits

Answer 4

Sphenoid, Frontal, Ethmoid

Question 5

What is the strongest portion of the orbital rim

Answer 5

zygomatic bone and zygomatic process of the frontal bone

Question 6

What is the downside to having a concavity?

Answer 6

makes the eye prone to injury

Question 7

what is the pros to having concavity

Answer 7

increases lateral visual field

Question 8

What is the purpose of the orbital rim

Answer 8

protection from trauma

Question 9

The orbital roof has a _____ shape?

Answer 9

triangular

Question 10

What bones make up the orbital roof

Answer 10

Frontal, lesser wing of the sphenoid bone (posterior to frontal bone)

Question 11

The lacrimal fossa holds what?

Answer 11

the lacrimal gland

Question 12

T/F the lacrimal gland can’t be seen in the shallow orbit

Answer 12

False; don’t misdiagnose as a tumor

Question 13

T/F The orbital rim is thin and mainly consists of the orbital plate of the maxillary bone

Answer 13

false; orbital floor. the orbital rim is thick and rounded at its anterior aperture

Question 14

T/F The orbital floor is the strongest orbital wall

Answer 14

false; weakest

Question 15

Orbital floor gives support to the eye and the ________ tissues and separates them from the ______sinus

Answer 15

adnexal; maxillary

Question 16

T/F The floor extends to the apex

Answer 16

false

Question 17

Orbital floor is \_\_\_\_\_\_ to \_\_\_\_\_ mm long 
a) 35-50
b)15-40
C)20-40
D)35-40

Answer 17

35;40

Question 18

T/F the floor easily deform to blunt trauma

Answer 18

T

Question 19

______ bone and lack of support _____ the rate of fractures

Answer 19

thin; increases

Question 20

Where does the floor blow out into in a blowout fracture

Answer 20

maxillary sinus

Question 21

Why does the floor blow into the maxillary sinus

Answer 21

it provides protection to the eye and tissues

Question 22

Patient has a BOF with loss of vision why?

Answer 22

Retinal detachment, retinal tear and/or optic nerve damage

Question 23

Patient has a BOF with diplopia why?

Answer 23

Because of muscle entrapment

Question 24

Patient has a BOF with enophthalmos why?

Answer 24

loss of support

Question 25

Patient has a BOF with numb cheek why?

Answer 25

for damaged to the infraorbital nerve

Question 26

What is enophthalmos?

Answer 26

sunken eye

Question 27

When will a BOF be repaired with surgery

Answer 27

restricted strabismus, enophthalmos

Question 28

When would you cause a BOF

Answer 28

Thyroid eye disease

Question 29

The lateral orbital wall is form by ______ and ______ bones and _______ in shape

Answer 29

zygomatic malar; greater wing of sphenoid bone; triangular

Question 30

The medial orbital wall is _____ and _______

Answer 30

smallest; thin

Question 31

A ______ _______ of the ethmoid bone is extremely thin

Answer 31

Lamina papyracea

Question 32

What protects the medial wall from being fractured

Answer 32

the honeycomb structure of the ethmoid sinus bony lamina

Question 33

Which wall is fractured most often

Answer 33

Orbital floor

Question 34

``` The globe reaches _____ of its adult size when an infant is _____ of age a) 90% 10months b)90% 20 months C)80% 10 months D)80% 20 months ```

Answer 34

90%; 20 months

Question 35

``` At birth the ______ diameter of the globe is _____ mm. In adulthood it is ____ mm a) 16 , 24 b)10, 24 C)16, 20 D)16, 10 ```

Answer 35

anteroposterior; A)16; 24

Question 36

What are the three factors that affect the size of globe?

Answer 36

refractive error (myopia), gender (males > females), ethnicity (Chinese smallest)

Question 37

``` The volume of the globe is _____cm^3 a) 7 b)10 C)9 D)8 ```

Answer 37

7

Question 38

``` The volume of the orbit is _____cm^3 a) 60 b)40 C)30 D)10 ```

Answer 38

30

Question 39

``` The vertical diameter of the globe is _____ and the horizontal diameter is _____ a) 23mm, 24 mm b)23mm, 25 mm C)23mm, 26 mm D)23mm, 23.5 mm ```

Answer 39

23 mm; 23.5 mm

Question 40

What is exophthalmos

Answer 40

forward displacement of the globe

Question 41

Why can you not use proptosis to describe exophthalmos

Answer 41

both are a forward displacement but proptosis is of any object and is not specific to the eyeball

Question 42

Why does any displacement of the eye cause the globe to move forward?

Answer 42

the only place the orbit can acutely(suddenly)expand is anteriorly

Question 43

As you age what decreases and what does it cause

Answer 43

fat content and it causes enophthalamos

Question 44

What is the most common cause of unilateral and bilateral exophthalamus in adults

Answer 44

Thyroid eye disease

Question 45

T/F Can thyroid eye disease be only unilateral

Answer 45

F; it is unilateral or bilateral

Question 46

What accumulates in the EOM's and/or connective tissue and fat and leads to swelling in thyroid eye disease

Answer 46

Glycosaminoglycans (GAG)

Question 47

What is craniofacial dysostosis and what can it cause

Answer 47

Defect in the normal ossification of fetal cartilages; exophthalmos

Question 48

What is a hemangioma and what can it cause

Answer 48

an abnormal buildup of blood vessels ; exophthalmos

Question 49

What is craniostenosis and what can it cause

Answer 49

fault (premature) in fusing of bones; exophthalmos

Question 50

What is buphthalmos and what can it cause

Answer 50

eye is stretched for some reason, all structures become longer; exophthalmos

Question 51

T/F severe hyperopia and buphthalmos may stimulate exophthalmos

Answer 51

False, severe myopia and buphthalmos may stimulate exophthalmos

Question 52

______ may lead to _____ exophthalmos of the contralateral eye

Answer 52

enophthalmos; pseudo

Question 53

What faults or defect in bones can cause exophthalmos

Answer 53

craniostenosis, craniofacial dysostosis

Question 54

What type of tumors can cause exophthalmos

Answer 54

inflammatory pseudotumors, benign and malignant tumors

Question 55

What abnormal blood vessel buildup can cause exophthalmos

Answer 55

hemangioma

Question 56

The amount of protrusion of the normal eye can be important _______ ________

Answer 56

clinical marker

Question 57

Where is the protrusion typically measured from

Answer 57

deepest part of the lateral orbital rim to the corneal apex

Question 58

What is the most accurate device in measuring protrusion

Answer 58

hertel exophthalmometer

Question 59

T/F a simple ruler cannot be used to measure protrusion

Answer 59

F; it can be used

Question 60

What three types of collagen make up the orbital connective tissue and describe them

Answer 60

CT I - structural integrity CT III - adhesion between connective tissue and adipocytes CT IV - basement membranes of connective tissue vessels

Question 61

What type of cells make up the orbital tissue

Answer 61

Fibroblasts and endothelial cells

Question 62

_____ percent of individuals have the _______ artery as the primary blood supply to the orbit. ______ percent of individuals have the _____ artery contribute equally through an accessory to ______ artery

Answer 62

96; Ophthalmic artery; 3; middle meningeal artery; ophthalmic

Question 63

T/F Orbital veins and arteries follow the same course in the system

Answer 63

F; the follow different course

Question 64

Orbital veins _____ parallel orbital arteries

Answer 64

do not; except lacrimal and ethmoidal veins

Question 65

T/F Orbital veins do not posses valves

Answer 65

T; valves prevent backflow