Orbit anatomy Flashcards
blowout fracture
contents sag into paranasal sinuses of frontal, ehtmoid, maxilla
four refractory mediums
cornea, aqueous humor lens, vitreous humor
what forms the CT elements (sclera, cornea, choroid, meninges) surrounding the optic cup?
head mesenchyme from neural crest
coloboma
retention of ventral cleft where hyaloid vessels run
optic cup becomes
two layers of retina (pigmented and visual). Separation results in detached retina
what is unique about the optic nerve
it is a direct brain fiber tract surrounded by CSF and meninges
Moving from anterior to posterior, cornea becomes__becomes___. Choroid becomes__
sclera then dura. arachnoid and pia
flow of aqueous humor
posterior chamber thru pupil to anterior into canal of Schlemm
Fovea centralis is in the
macula lutea
muscles of the iris and their innervations
pupil sphincter (parasymp); pupil dilator (symp).
contraction of the ciliary muscle
slackens suspensory ligaments and rounds lens for close vision (parasymp)
flow of lacrimal secretions
gland-conjuctival sac-papillae with puncta-canaliculi-lacrimal sac-nasolacrimal duct-inferior meatus of nasal cavity
glands of the eyelid
ciliary (obstruction=sty) and tarsal (chalazion)
what muscle is directly above superior rectus
levator palpebrae superioris
actions of superior oblique, inferior
abduct and depress, abduct and elevate
where do the rectus muscles originate
anulus tendineus. all nerves except trochlear pass thru it.
adductors of eye
medial recuts plus superior and inferior rectus
how would you test the inferior oblique? Superior rectus?
look in then up. look out then up. For depressors and elevators you reverse the ad/abduction action
position of pupil in oculomotor nerve palsy
down and out
innervation of lateral rectus and superior oblique
abducens (VI), trochlear (IV)
branches of V1 (opthalmic division). what do they supply
frontal, lacrimal, nasociliary. general sensory, postsynaptic parasymp, postsynaptic symp
pathway of parasympathetics
exit brain with III, synpase in ciliary ganglion, follow short ciliary branches of V1 to constrictor and ciliary muscles
with what nerve do lacrimal parasympathetics travel
NOT lacrimal nerve. Exit brain with facial (VII), synapse, follow V2 branches
sympathetic muscles of eye
dilator of pupil and superior tarsus (helps LPS)
contents of optic canal
ophthalmic artery, optic nerve, central artery of retina w/in optic nerve
