Last lecture 2 Flashcards

1
Q

how does the medial rectus move the eye?

A

moves the eye towards the nose (medially)

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2
Q

how does the lateral rectus move the eye?

A

moves the eye away from the nose (laterally)

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3
Q

superior rectus moves the eye how?

A

moves the eye up and laterally

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4
Q

inferior rectus moves the eye how?

A

moves the eye down and laterally

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5
Q

superior oblique moves the eye how?

A

rotates eye so top of the eye moves towards the nose, intortion (pupil points down and medially.

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6
Q

inferior oblique moves the eye how?

A

rotates eye so top of the eye moves away from the nose, extortion pupil points up and medially.

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7
Q

what are the main muscles of the eye?

A

superior rectus, medial, lateral and inferior rectus

the superior and inferior oblique

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8
Q

describe the wagon wheel test

A

the patient holds their head still while the practitioner moves a pen in several directions from a start. always returning to the center before changing direction.

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9
Q

informal testing of eye movements is always part of _____ exams.

A

neurological.

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10
Q

what is known as the “quick and dirty” eye test?

A

the H shape follow my finger test.

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11
Q

how do you test each muscle individually, bc in the H shape test more than one muscle is acting to produce a specific movement.

A

the clinician needs to ask them to move their eye into the gaze position

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12
Q

the gaze position is what?

A

22 degrees laterally from the visual axis. in this position, the six cardinal movements of gaze are tested only a single muscle is tested by moving through the H shape while in a line of gaze.

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13
Q

using the visual axis, each movement is produced by what?

A

extraoccular muscles ( at least two) working together

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14
Q

initially, the longitudinal axis through the orbit is about? what does this mean
?

A

22 degrees off the longitudinal axis through the eyeball. ( visual axis)

that means that the contraction of the superior and inferior oblique will move the eyeball not only up but towards the midline (medially)

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15
Q

the actions of lateral and medial recti are simple, the medial recti ____ the eyeball while the lateral rectus ___ the eye

A

adduct (cross eyed)

abducts (hence the ABducens nerve innervation of lateral rectus)

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16
Q

what would a lesion of CN VI result in?

A

lesion would result in paralysis of the lateral rectus and the inability to abduct the pupil. the patient would present with an adducted eye due to the unopposed pull of the medial rectus of the affected eye.

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17
Q

superior rectus raises pupil ___ and ___

A

upward and laterally

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18
Q

inferior rectus pulls pupil ___ and ___

A

downward and laterally

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19
Q

what is the lateral direction of both the rectus (superior and inferior) due to?

A

the fact that the sup. and inf. rectus muscles are attached posteriorly and medial to the position of the eyeball in the orbit.

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20
Q

what are the oblique muscles attached to? vs recti muscles?

A

the posterior half of the globe of each eyeball.

recti muscles are attached to the anterior half of this globe.

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21
Q

when an oblique muscle acts it wants to ____ the eyeball in the orbit

A

rotate

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22
Q

the superior oblique will pull from the ____ of the eyeball, pulling it?

A

back, pulling it inferiorly and medially

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23
Q

the inferior oblique will pull from the ____ aspect of the back of the eyeball, pulling it?

A

inferior aspect, pulling it up and medially.

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24
Q

the primary action of the superior and inferior oblique mm (w/o the visual axis aligned with the line pf pull) is to ?

A

rotate the eyeball around the visual axis.

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25
Q

the superior oblique will produce ____ while the inferior oblique will produce ___

A

sup: intorsion (medial/inward rotation of the top of the eyeball)
inf: extorsion(lateral/outward rotation of the top of the eyeball)

26
Q

the secondary actions of the sup/inf obliques are around the horizontal axis are ____ and ____

A

depression (superior) and elevation (inferior)

27
Q

a lesion of CN IV would result in ?

A

the inferior oblique being unopposed, (intorsion no longer possible) eyeball is extorted

28
Q

what does a lesion of CN IV resulting in extorsion of the eyeball result in as far as vision?

A

diplopia (double vision)

29
Q

what characteristic will a patient with extorsion of the eye (lesion to trochlear n ) exhibit?

A

head tilt, with paralysis of the superior oblique in an attempt to maintain the vertical axis of the eye to minimize double vision.

30
Q

the eyeball is composed of ___ layers

A

3

31
Q

what is the external layer of the eye?

A

fibrous layer

posterior 5/6 is the opaque sclera
ant 1/6 is the transparent cornea.

32
Q

what is the middle later of the eye?

A

vascular layer that is composed of 3 different regions anterior to posterior.

33
Q

what are the three different regions of the middle layer of the eye moving ant/post

A

ANT: the choroid
middle: ciliary body
Post: iris

34
Q

what is the choroid?

A

a layer adherent to the retina and terminates at the ciliary body

35
Q

what is the ciliary body

A

middle region of the second later of the eye that is connecting the choroid to the iris

36
Q

what is the iris ?

A

most posterior region of the 2nd layer of the eye that is a contractile diaphragm anterior to the lens of the eye.

37
Q

what makes up the most internal layer of the eye? what does it contain and what is it responsible for?

A

the retinal layer is a very thin, delicate membrane containing bipolar neurons responsible for relaying visual stimuli to the brain.

38
Q

what is the circular pale area that is posterior to the retina?

A

the optic disc

39
Q

the optic disc is where the ___ ___ enters the eye and its fibers ?

A

optic nerve enters the eye and its fibers spread out into the retinal layer.

40
Q

the optic disc contains ___ only and no ___ ___. meaning what?

A

fibers only and no receptor cells meaning it is a blind spot. in the retina.

41
Q

lateral to the optic disc, is a yellowish oval area known as the?

A

macula lutea.

42
Q

the macula lutea has a central depressed spot called the )___ ____. which is the area with the greatest?

A

fovea centralis the area of greatest visual activity.

43
Q

lesser reattachment of the retina does or does not occur in the fovea centralis?

A

does not occur.

44
Q

4 components of the refractive media of the eyeball, all. with differing density through which light must pass through on its way to the retina, what are they?

A

cornea, aqueous humor, lens, and vitreous body

45
Q

the cornea is continuous with the ___ at what junction?

A

sclera at the sclerocorneal junction

46
Q

the cornea is ____ and ___. what implications does this have?

A

cornea is transparent and avascular, being avascular means that there are long healing periods for abrasions of the cornea.

47
Q

what is the aqueous humor?

A

clear watery fluid in the anterior and posterior chambers of the eyeball.

48
Q

what produces the aqueous humor of the eyeball? how does it get to both post and ant chambers?

A

the ciliary process, and passes from the posterior chamber to the anterior chamber via the pupil.

49
Q

how is the aqueous humor drained away?

A

through spaces at the iridocorneal angle (filtration angle)

50
Q

what do the filtration spaces of the eye drain to? blockage leads to what?

A

these spaces drain into a circular venous canal.

blockage of this drainage leads to increases pressure in the compartment (glaucoma)

51
Q

what does the aqueous humor provide for the avascular cornea and lens?

A

nutrients

52
Q

what is the lens/

A

a transparent biconvex structure held within a transparent capsule.

53
Q

what is the lens surrounded by? and what arises from this strucutre?

A

the lens is surrounded by ciliary processes from which the highly elastic, radially-arranged suspensory ligament of the lens arises.

54
Q

the curvature of the lens is altered by what?

A

the contraction/relaxation of the suspensory ligament of the lens.

55
Q

what is the name of the condition where lens transparency is lost>?

A

cataracts.

56
Q

what fills the eyeball posterior to the lens?

A

vitreous body. which is a jellu like matrix with a fine meshwork of collagen fibers.w

57
Q

what fills the vitreous chamber of the eye?

A

vitreous body (gel)

58
Q

what happens after about age 60 to the vitreous body?

A

the matrix is not continually replaced and it becomes shrunken that it pulls away from the back of the eyeball. often causing the detachment of the retina.

59
Q

the inward movement of the ciliary body relaxes the ___ ___ which in turn relaxes the ___ ___ ___ ___. allowing it to bulge anteriorly and collect more light.

A

suspensory ligaments, capsule of the lens.

60
Q

distance focus: how is the pupil, ciliary muscle, and suspensory ligaments

A

relaxed ciliary muscle
taught suspensory ligaments (thin lens)
dilated pupil