6. anatomy of the eye (lecture) Flashcards
which gland supplies the eye?
lacrimal canal (lateral upper)
where do secretions from the lacrimal canal drain?
across eye, medially to lacrimal canal –> lacrimal sac (top of nose) –> nasolacrimal duct –> inferior meatus of nasal cavity
what drains into inferior meatus and what drains into middle meatus?
only nasolacrimal duct (tears) drain into inferior meatus
all sinuses drain into middle meatus
which bones make up the bony orbit of the eye?
frontal zygomatic ethmoid sphenoid lacrimal maxilla
which bone contains the openings into the orbit?
sphenoid:
superior and inferior orbital fissure
optic canal
what forms the apex of the orbital?
optic canal
what is significant about the optic canal?
where the optic nerve enters the orbit
what forms the roof of the orbit?
frontal and sphenoid bones
sphenoid contains openings into orbit
what forms the lateral wall of the orbit?
zygomatic + sphenoid bone
what forms the medial wall of the orbit?
ethmoid
maxillary
lacrimal
sphenoid
what forms the inferior (base) of the orbit?
maxillary (teeth)
zygomatic bones (infero-lateral)
(weakest part of orbit)
main openings into the orbit?
- optic canal
- superior orbital fissure
- inferior orbital fissure
- nasolacrimal canal
how do you remember which structures pass through the superior orbital fissure? (sphenoid bone)
live frankly to see absolutely no insult
what does live frankly to see absolutely no insult stand for?
Lacrimal and Frontal (ophthalmic V1), Trochlea (IV), Superior oculomotor (III), Abducens (VI), Nasociliary (ophthalmic V1), Inferior oculomotor (III)
Superior Ophthalmic Vein AS WELL
what travels through the optic canal? (sphenoid bone)
optic nerve
opthalmic artery
what travels through the inferior orbital fissure? (sphenoid bone)
inferior ophthalmic vein
maxillary (V2)
sympathetic nerves
what is the function of the lens?
focus light on the back of retina
what is the lens stretched by? why?
by suspensory ligament
to change focus - causing long / short sighted
what does suspensory ligament attach lens to?
ciliary bodies (process and muscle)
what sits around the lens?
iris
with aperture being pupil
light through pupil into lens to back of retina
what is the macula / fovea?
most focused area with the most photoreceptor cells
converts light energy to nerve signals
what is significant about the optic canal?
optic nerve and ophthalmic artery enters orbit
no photoreceptor cells - blind spot
what is filled behind the lens of the eye?
vitreous humor
what is filled in front of the lens?
aqueous humour in anterior and posterior chambers
behind cornea and in front of iris / lens
what divides the anterior from the posterior chamber?
iris
anterior chamber - anterior to iris
posterior chamber - posterior to iris
what covers the posterior eyeball? (external to internal)
sclera (external layer)
choroid (vascular layer)
retina (rod and cone cells)
what is contained within the outer fibrous layer of the eye?
sclera (posterior)
cornea (anterior)
what is contained within the middle vascular layer of the eye?
iris
choroid (CT + vessels)
ciliary body (muscle + process)
what is contained within the inner layer of the eyeball?
retina (neural and pigmented layer)
non-visual retina (anterior)
optic retina (posterior, lateral)
what is the function of the middle vascular layer?
helps supply nutrients to avascular areas of the eye (diffuse)
what is examination of the eye called? what do you use?
fundoscopy
using an opthalmoscope
