Eye Flashcards
Orbits borders
superior- frontal sinus
Laterally - Temporel fossa
inferiorlly- maxillary sinus
medially- ethmoid air cells and sphenoid air sinus
orbit base
orbital margin surrounding the orbital opening
orbit walls and apex
Superior wall- orbital plate of the frontal bone
lateral wall - zygomatic bone
floor- maxilla
medial wall - orbital plate of the ethmoid
apex- optic canal
contents of orbit
eyeball
extraocular muscles
sensory, motor nerves and vascular supply
orbital fascia
mucous membrane
extraocular fat
concentric layers of tissue
encloses the lens, vitreous body, and aqueous humor
- external fibrous tunic
- Middle vascular tunic - uvea
- internal nervous tunic - retina
external fibrous tunic
composed of the cornea and sclera
cornea
Anterior transparent portion of the fibrous tunic
Responsible for most of the light refraction that occurs in the eye
sclera
posterior opaque part of the fibrous tunic
Receives tendon of the muscles of the eye
middle vascular tunic
(uvea)
choroid
ciliary body
iris
choroid
brown coat that lines the posterior two thirds of the sclera
ciliary body
thickening of the vascular tunic at the level of the corneoscleral junction
gives rise to ciliary processes which produce aqueous humor, and give attachment to the suspensory ligament of the lens
Contains the ciliary muscle is responsible for accommodation
iris
divides the space between the cornea and lens into anterior and posterior aqueous Chambers
Pigment cells responsible for color
internal nervous tunic (retina)
Innermost layer, which contains special receptors cells upon which is projected an inverted image of objects seen
Aqueous humor
clear fluid produced by ciliary processes, posterior to the iris
passes through the people to the anterior chamber
Produces nourishment for the cornea and lens
Lens
Transparent, structure enclosed in a capsule and suspended between the aqueous humor and vitreous body by the ciliary zonules
Vitreous humor
clear liquid that fills the space posterior to the lens
Rectus muscles
superior CN3
Inferior CN3
Medial CN3
Lateral CN6
all for muscles, originate from in common tenements ring that surrounds the optic canal and superior orbital fissure
They extend anteriorly to insert into the anterior portion of the sclera
Extraocular muscles
superior oblique
Inferior oblique
superior oblique
Originates from body of the sphenoid bone passes through the trochlea (cartilaginous, sling) and inserts on the posterior lateral aspect of the sclera (deep to the superior rectus muscle)
Innervation CN IV
inferior oblique
Originates from the anteromedial aspect of the floor of the orbit, and inserts into the Posterolateral aspect of the sclera (deep to the lateral rectus muscle)
Innervation CN3
Ophthalmic nerve
CNV V1
Three Divisions
lacrimal nerve
frontal nerve
Nasociliary nerve
Ciliary ganglion
found in the posterior extent of the orbital cavity
Contains nerve cell bodies of the postganglionic parasympathetic neurons that control that eye
Supported by the trigeminal nerve
Preganglionic fibers arise from CN3
Vascular supply
ophthalmic artery
Branches
Lacrimal artery
Supraorbital
Supratrochlear
Central artery of the retina
ciliary arteries
lacrimal apparatus
Location- anterior superlateral corner of orbit
lacrimal papillae
Small hillocks at the medial end of each eyelid
lacrimal puncta
openings of the lacrimal canaliculi at the apex of the lacrimal papillae
lacrimal canaliculi
Small ducts that extend from the lacrimal puncta to the nasolacrimal sac
Nasolacrimal sac
Small saclike structure of the anterior medial margin of the orbital floor
receives the lacrimal canaliculi
nasolacrimal duct
Drains the lacrimal sac into the inferior meatus of the nasal cavity
Eyelids
Musculofibrous folds in front of each
Tarsal plate
Muscles
-Orbicularis oculi
-Levator palpebrae superioris
