Orbit

Front 1

Bony Orbit:
general boundaries

Back 1

Superior: orbital portion of frontal bone
Inferiorly: orbital portion of maxillary bone (/maxillary sinus)
Medial wall: paper thin: ethmoid
Lined by periosteum: periorbita

Front 2

7 bones of the Bony Orbit

Back 2

1. sphenoid (lesser wing, w/optical canal)/sup. orbital fissure/ sphenoid (greater)
2. frontal bone
3. maxillary bone
4. zygomatic bone
5. lacrimal bone
6. ethmoid (medial)
7. palatine bone: orbital tip of vertical plate

Front 3

Superior Orbital Fissure

Back 3

Between lesser wing and greater wing of sphenoid bone

Front 4

Inferior Orbital Fissure

Back 4

Between greater wing sphenoid and maxilla

Front 5

V-2 and the orbit

Back 5

V-2 = maxillary branch of trigeminal CN

sensory only;
exits at infraorbital fossa

Front 6

Supraorbital foramen

Back 6

V-1: opthalmic branch of trigeminal (CN V)
sensory only
+ supraorbital artery

Front 7

Supraorbital margin

Back 7

transition b/wn squamous and orbital frontal bone

Front 8

Supraciliary arch

Back 8

bony ridge deep to eyebrows and above supraorbital margin...

boxer's get cut here

Front 9

Orbit is near paranasal sinuses

Back 9

Orbital trauma:
Blowout Fx

...into paranasal sinuses

Front 10

Eyelid

Back 10

Sup palpebrae

Inf palpebrae

Front 11

Eyelid (palpebrae) functions

Back 11

1. control light
2. protect cornea
3. spread lacrimal fluid

Front 12

Skeleton of eyelids -
really connective tissue

Back 12

Sup/Inf. tarsus or tarsal plates

Front 13

Eyelid skin

Back 13

External: loose; allows extreme sub-cutn swelling

Internal: mucus membrane: conjunctiva

Front 14

Eyelid glands

Back 14

1. tarsal glands
2. ciliary glands- sebaceous glands of eyelash hair follicles

Front 15

Lacrimal Gland

Back 15

1. fossa is up and out from eyeball

2. secrete lacrimal fluid
a. lubricates
b. nutrition
c. antibiotic properties

Front 16

Angles of the eye

Back 16

where the eyelids join

later angle & medial angle

Front 17

Superior eyelid (palpebra)
components

Back 17

3 mm:
1. levator palpebrae: CN III 3
2. sup. tarsal m: symp elevation
3. orbicularis oculi-palpebral part : CN VII 7...depresses

2 glands
1. tarsal glands = lube
2. ciliary glands = sty

eyelashes

Front 18

Conjunctiva

Back 18

1. palpebral - lines eyelid

2. bulbar - lines sclera

mucous membrane for eyelid movement

Front 19

CC:
subconjunctival hemorrhage

Back 19

bleeding between conjunctiva and sclera...usu harmless; HTN, eye trauma

Front 20

lacrimal appartus

Back 20

drains tears through lac papilla/w punta (medial edges eyelash) through lac canaliculi to lac sac through lac duct to inferior meatus of nose

Front 21

3 Coats for the Eye

Back 21

1. outer: sclera + cornea
2. middle vascular: iris: ciliary body + choroid
3. inner: retina: pigmented epi & neural retina

Front 22

nerve to cornea

Back 22

V1-branch: nasociliary

Front 23

cranial nerves in the orbit

Back 23

2, 3, 4, 5-1, 6

2 via optic canal
all others = sup. orbital fissure

Front 24

branches of V-1 in eye

Back 24

1. lacrimal n.
sensation in/around lacrimal gland;
DOES NOT cause lacrimination

2. frontal n.
i. supraorbital n.
ii. supratrochlear n.

3.nasociliary n
i. infratrochlear
ii. ethmoidal nn: ant & post.
iii. ciliary nn: long & short

Front 25

EOMI

Back 25

extraocular eye movements intact

Front 26

Opthalamic artery

...crosses CN II

Back 26

-1st br internal carotid in cranial vault

major branches
1. central a. --> neural retina
2. long/short posterior ciliary a.

Front 27

Central artery/vein retina

Back 27

Branch off opthalamic artery
Main blood supply to eye!

-damage it, damage neural retina
-diabetic retinopathy

Front 28

Venous drainage from orbit

Back 28

sup/inf opthalamic v
drains into cavernous sinus
via superior orbital fissure

recall: 1 fnc dural sinus = receive venous bloos from brain

Front 29

In the wall of the cavernous sinus

Back 29

O TOM:

CN 3, 4, 5-1, 5-2

Front 30

Within the sinus itself

Back 30

(O TOM) CAS

-internal carotid artery
-CN 6
-sympathetics
-sip/inf opthalamic vv