Orbit and the Eye Pt. 1 Flashcards Preview

Head and Neck Anatomy > Orbit and the Eye Pt. 1 > Flashcards

Flashcards in Orbit and the Eye Pt. 1 Deck (31)
Loading flashcards...
1

Seven Bones of the Orbit

Frontal
Ethmoid
Sphenoid
Maxilla
Zygomatic
Palatine
Lacrimal

2

Four walls of the orbits

Lateral, medial, roof and floor

3

Lateral Wall consists of:

zygomatic bone and greater wing of the sphenoid bone.

4

Medial wall

Ethmoid and lacrimal bones
(and includes the anterior and posterior ethmoidal foramina int he frontosphenoid suture)

5

Roof

Orbital plate of the frontal bone

6

Floor

Orbital surface of the maxilla, very thin.

7

The inferior orbital fissure is continuous with the ___________ canal which opens onto the face via the infraorbital foramen.

infraorbital canal

8

Eyeball is about ____ cm in diameter

2.5

9

True/False: There are no lymph vessels in the orbit.

True.

10

The orbit contains (8):

eye
optic nerve
EOMs
lacrimal apparatus
fat
fascia
nerves
vessels

11

(2) orbital fascia

periorbita (periosteum lining bones of orbit)
common tendinous ring (origin of the four rectus muscles)

12

Rectus muscle origin and insertion?

Origin: common tendinous ring
Insert: anterior half of the eye

13

Obliques and levator origin and insertion

origin: bones of orbit
insert: obliques - posterior half of eye
levator palpebrae superioris - superior tarsus (upper eyelid)

14

Lateral and medial rectus actions?

Lateral: ABducts eye
Medial: ADducts eye

15

Inferior and superior oblique muscle actions?

Inferior Oblique: Up and Out
Superior Oblique: Down and Out

16

Superior and inferior rectus muscle actions?

Superior Rectus: Up and In
Inferior Rectus: Down and In

17

SR + SO Intort/extort eye?

Intort eye

18

IR + IO intort/extort eye?

Extort eye

19

elevation by?

IO and SR

20

Depression by?

SO and IR

21

ABduction by?

LR + IO + SO

22

ADduction by?

MR + IR + SR

23

SO and IO raise and lower eye when held in AB/ADduction?

ADduction

24

SR and IR raise and lower eye when held in AB/ADduction?

ABduction!

25

Special Afferent (SA)

Optic Nerve (II)
Optic nerve carries SA fibers from retina to the visual centers of the brain. Has dural coverings; extension of the brain.

26

General Afferent (GA)

Ophthalmic Nerve (V1) which contains:
1. Frontal n.
2. Lacrimal n.
3. Nasociliary n.

Long ciliary nerves (general afferents from the eye)

27

General Efferent (GE)

Oculomotor Nerve (III) --> all EOMs except:
Trochlear Nerve (IV) --> sup. oblique m.
Abducent nerve (VI) --> lat rectus m.

28

VI Lesion

- Loss of LR m (out)
- affected eye turns medially
- diplopia

29

IV lesion

- loss of SO m (down and out)
- Head is tilted away from the affected side
- Affected eye is slightly higher and deviated medially.
- may have diplopia.

30

III lesion; oculomotor palsy

paralysis of all EOMs except LR and SO.
- upper eyelid ptosis
Pupilary dilation
- poor near focus