Orbital Region, Orbit, and Eyeball Flashcards
If a person receives a blow directly on the bony rim of the orbital, where will the fractures most likely occur?
At the three sutures of the bones forming the orbital margin.
The thinness of the medial and inferior walls of the orbital makes what possible?
A blow to the orbital may leave the margins intact, but fracture the orbital walls.
What is a blowout fracture?
Indirect traumatic injury that displaces the orbital walls.
Side effects of an orbital fracture?
Typically intra-orbital bleeding, which will lead to increased pressure and eventually exophthalmos.
In what ways could trauma to the eye affect local structures?
Bleeding into maxillary sinus, displacement of maxillary teeth, fracture of nasal bones ,airway obstruction, etc.
Concerns with a malignant tumor in the sphenoidal and posterior ethmoidal sinuses?
They can erode orbit walls and compress the optic nerve and orbital contents.
Result of a tumor in the orbital?
Exophthalmos.
A fully-medially turned eye will have how much exposure?
2.5 cm.
What side of the eye is typically used in eyeball surgeries?
Lateral
Lesion of what nerve will inhibit palpebrae superioris?
III
Other than III, what nerve could be damaged to inhibit eyelid closure.
VII
Side effects of a loss of VII innervation to the eye?
Loss of tonus in the muscle of the inferior eyelid, everted, and eventually drying of cornea. This will cause excessive and inefficient lacrimation.
Aside from a nerve lesion, an alternate cause of excess lacrimal fluid?
Obstruction of Lacrimal drainage. Dabbing will further irritate.
Side effect of cilary obstruction of the eyelid?
Painful, red, pus-producing swelling (Sty)
Sebaceous obstruction of the eyelid?
Chalazia
Side effects of obstruction of tarsal gland?
Tarsal chalazion - inflammation/swelling protruding toward the eyeball and rubbing it as the eyelids blink.
What is hyperemia of conjunctiva?
Bloodshot eyes caused by local irritation
What is Conjunctivitis?
Inflammed conjunctiva, often caused by an infection of the eye.
What are subconjunctival hemorrhages?
Bright or dark red patches deep to and within the bulbar conjunctiva caused by injury or inflammation. Injuries could range from a blow to the eye or an especially powerful sneezing.
The retina and optic nerve develop from the..
optic cup, a part of the optic vesicle.
The pigment cell layer is on the _______. The neural retina is on the _____ later.
Outside. Inside.
What separated the layers of developing retina embryonically?
An Intraretinal Space
What occurs in a patient with a detached retina?
Seepage of fluid btw the cell layers, causing initially flashes of light or specks floating in the eye. Eventually potential for vision loss.
Describe the pupillary light reflex.
Tests CN II and III. When light enters one eye, but pupils should contract because the retina sends fibers into the optic tracts on either side.
