Orbit anatomy

Question 1

blowout fracture

Answer 1

contents sag into paranasal sinuses of frontal, ehtmoid, maxilla

Question 2

four refractory mediums

Answer 2

cornea, aqueous humor lens, vitreous humor

Question 3

what forms the CT elements (sclera, cornea, choroid, meninges) surrounding the optic cup?

Answer 3

head mesenchyme from neural crest

Question 4

coloboma

Answer 4

retention of ventral cleft where hyaloid vessels run

Question 5

optic cup becomes

Answer 5

two layers of retina (pigmented and visual). Separation results in detached retina

Question 6

what is unique about the optic nerve

Answer 6

it is a direct brain fiber tract surrounded by CSF and meninges

Question 7

Moving from anterior to posterior, cornea becomes__becomes___. Choroid becomes__

Answer 7

sclera then dura. arachnoid and pia

Question 8

flow of aqueous humor

Answer 8

posterior chamber thru pupil to anterior into canal of Schlemm

Question 9

Fovea centralis is in the

Answer 9

macula lutea

Question 10

muscles of the iris and their innervations

Answer 10

pupil sphincter (parasymp); pupil dilator (symp).

Question 11

contraction of the ciliary muscle

Answer 11

slackens suspensory ligaments and rounds lens for close vision (parasymp)

Question 12

flow of lacrimal secretions

Answer 12

gland-conjuctival sac-papillae with puncta-canaliculi-lacrimal sac-nasolacrimal duct-inferior meatus of nasal cavity

Question 13

glands of the eyelid

Answer 13

ciliary (obstruction=sty) and tarsal (chalazion)

Question 14

what muscle is directly above superior rectus

Answer 14

levator palpebrae superioris

Question 15

actions of superior oblique, inferior

Answer 15

abduct and depress, abduct and elevate

Question 16

where do the rectus muscles originate

Answer 16

anulus tendineus. all nerves except trochlear pass thru it.

Question 17

adductors of eye

Answer 17

medial recuts plus superior and inferior rectus

Question 18

how would you test the inferior oblique? Superior rectus?

Answer 18

look in then up. look out then up. For depressors and elevators you reverse the ad/abduction action

Question 19

position of pupil in oculomotor nerve palsy

Answer 19

down and out

Question 20

innervation of lateral rectus and superior oblique

Answer 20

abducens (VI), trochlear (IV)

Question 21

branches of V1 (opthalmic division). what do they supply

Answer 21

frontal, lacrimal, nasociliary. general sensory, postsynaptic parasymp, postsynaptic symp

Question 22

pathway of parasympathetics

Answer 22

exit brain with III, synpase in ciliary ganglion, follow short ciliary branches of V1 to constrictor and ciliary muscles

Question 23

with what nerve do lacrimal parasympathetics travel

Answer 23

NOT lacrimal nerve. Exit brain with facial (VII), synapse, follow V2 branches

Question 24

sympathetic muscles of eye

Answer 24

dilator of pupil and superior tarsus (helps LPS)

Question 25

contents of optic canal

Answer 25

ophthalmic artery, optic nerve, central artery of retina w/in optic nerve