Ocular Motility Pt. 1 Flashcards
How many extraocular muscles are attached to the eyeball?
6
What are the names of the 6 extraocular muscles?
4 rectus muscles (inferior, superior, lateral, and medial) and 2 oblique muscles (inferior and superior)
The manner in which these extraocular muscles “grip” the eyeball allows it to move in 3 different planes: _____, _____, and _____
Horizontal, Vertical, and Torsional
What are the Cardinal positions of gaze?
right and up, right, right and down, left and up, left, left and down
The muscle that moves the eye in a particular direction of gaze is called the _______
Agonist
The muscle of the same eye that opposes that action is call the _____
Antagonist
What are the 3 cranial nerves that extend from the brainstem to the 6 extraocular muscles?
- Oculomotor/3rd cranial nerve
- Trochlear/4th cranial nerve
- Abducens/6rg cranial nerve
What does the oculomotor/3rd cranial nerve power?
superior rectus, inferior rectus, medial rectus, and inferior oblique muscles
What does the trochlear/4th cranial nerve power?
superior oblique muscle
What does the abducens/6th cranial nerve power?
lateral rectus muscle
Areas in the brainstem regulate _____________ to yoke muscles so that the right medial rectus and the left medial rectus are afforded equal nerve supply power to move the eyes smoothly and simultaneously to the left
the distribution of power
When both eyes move in the same direction, the movements are said to be _______
Conjugate
_________ eye movements are simultaneous movements of both eyes in opposite directions
Disconjugate
The most important disconjugate movement is _______, which occurs when both eyes move inward
Convergence
Abnormal eye alignments are also referred to as ______
Strabismus
________ eye misalignments are constant in all fields of gaze
Comitant
_______ eye misalignments have different amounts of deviation in different fields of gaze
Incomitant
Strabismus is characterized as ___, ____, ____, or _____
Eso- (eyes go in), Exo- (eyes go out), hypo- (one eye goes down), or hyper- (one eye goes up)
Strabismus can be ______, consistently present, or ______, present only when fixation is interrupted
Manifest/Latent
All _______ are manifest deviations and all _______ are latent deviations
-Tropias/-Phorias
What are the 2 primary tests used to evaluate eye movement abnormalities?
Corneal light reflex observation and Cover testing
The ________ test involves observing the position of the corneal light reflex relative to the pupil
Hirschberg
The ______ test uses prisms to “balance” the light reflexes in the center of the pupils to more accurately measure the deviation
Krimsky
This kind of test involves the use of an occluder to cover one eye and thereby disrupt its fixation.
Cover-Uncover testing
If there is no movement observed in the cover-uncover test, then an _________ test is performed to detect a phoria. (this test disrupts the patients ability to fuse by not allowing them to use both eyes at the same time)
Alternate cover test
This test is used to measure the quantity of ocular misalignment using prisms and an occluder
Prism and alternate cover test
The unit of measure of the refractive power of a prism
Prism Diopter
Strabismus prevents _______, the ability of the brain to merge the 2 images received from each eye into a single binocular image
Fusion
Adults complain of _________ when their fusion is disrupted
Diplopia
