Orbit and Contents

Question 1

sclera

Answer 1

the white of the eye

Question 2

corneoscleral junction

Answer 2

limbus- where the cornea meets the sclera

Question 3

bulbar conjunctiva

Answer 3

covers the visible sclera

transparent

Question 4

palpebral conjunctiva

Answer 4

continuation of bulbar conjunctiva on posterior eyelids

Question 5

medial and lateral canthus

Answer 5

where the upper and lower eyelids meet

Question 6

lacrimal caruncle

Answer 6

medial canthus- site of tear drainage

Question 7

lacrimal papilla and puncta

Answer 7

site of tear drainage at medial canthus

Question 8

what shape is the orbit?

Answer 8

cone

Question 9

what is the orientation of the axis of the orbit

Answer 9

the orbit axis is directed laterally

Question 10

what bones make up the walls of the orbit?

Answer 10

medial- ethmoid, lacrimal, maxillary

roof- orbital process of frontal

lateral- zygomatic, gr. wing sphenoid

apex- gr wing sphenoid, lesser wing sphenoid

Question 11

what is the periosteum of the orbit?

Answer 11

periorbita- membrane encasing all objects of the orbit

Question 12

superior orbital fissure- what bone and what structures pass through it

Answer 12

between wings of the sphenoid

opthalmic nerve,,
oculomotor, trochlear, and abducens

opthalmic veins

Question 13

optic canal- what bones and what structures pass through it

Answer 13

in the lesser wing

optic nerve, opthalmic artery

Question 14

inferior orbital fissure- what structures pass through it

Answer 14

zygomatic nerve (V2)

Question 15

zygomatic foramen- what structures pass through it

Answer 15

zygomatic nerve

Question 16

anterior and posterior ethmoid canal- what structures pass through it

Answer 16

anterior and posterior ethmoid nerves

Question 17

lacrimal canal- what structures pass through it

Answer 17

nasolacrimal duct

Question 18

intorsion v extorsion

Answer 18

intorsion- twisting medially and down

extorsion- twisting medially and up

Question 19

name the muscles of the eye and their motions

Answer 19

medial (adducts), lateral (abducts), superior (elevates, adducts, intorts) and inferior rectus (depresses, abducts, exorts)

inferior and superior oblique

Question 20

levator palpebrae superioris and superior tarsal muscle

Answer 20

levator palpebrae attached via superior tarsal muscle to tarsal plate. opens eye

superior tarsal muscle is tonically activated via sympathetics

Question 21

describe the branches of the trigemnial nerve as it goes through the superior orbital fissure

Answer 21

the opthalmaic branch of trigeminal goes through the superior orbital fissure
it splits into the nasociliary, lacrimal, and frontal branches

the nasociliary gives off the short ciliary (into eye- sensory and para) and long ciliary

the nasociliary divides into the anterior ethmoidal and infratrochlear

the frontal divides into the supraorbital (forehead) and supratrochlear (sensory, medial eyebrow)

lacrimal supplies skin over lateral eyebrow and lacrimal gland

Question 22

what structure runs with the nasocilliary nerve

Answer 22

opthalmic artery

Question 23

how is the cilliary muscle innervated?

Answer 23

parasympathetic innervation from short ciliary nerve

Question 24

how does the ciliary muscle work?

Answer 24

contraction of ciliary muscle takes tension off of suspensory ligaments, allowing the lense to take a rounder shape

Question 25

sympathetic innervation to eye

Answer 25

come up sympathetic chain and thru superior cervical ganglion where they synapse

postganglionic cells follow carotid arteries to eye

dilate eyes and innervate superior tarsal muscle to maintain upper eyelid elevation

Question 26

meibomian glands

Answer 26

found in the tarsal plate- secrete oily secretion into the edge of the eyelid and tears

Question 27

chalazion

Answer 27

blockage of the meibomian glands

Question 28

pinguecula

Answer 28

yellow-white deposit adjacent to the limbus

thickened CT

degenerative

result of chronic irritation, doesnt effect vision

Question 29

pterygium

Answer 29

vasculatory inflammatory tissue growing from medial eye

result of chronic irritation, doesnt effect vision

Question 30

lacrimal ducts

Answer 30

tubuloalveolar gland w/ serous acini

located in the superolateral orbit

tears drain into lacrimal sac through lacrimal puncta and canaliculi

Question 31

central retina artery

Answer 31

artery seen in fundus of the eye

Question 32

venous drainage of orbit

Answer 32

superior and inferior opthalmic veins drain through superior orbital fissure in cavernous sinus

these veins communicate with deep and superficial face structures, providing a route for spread of infection from sinuses