Brainstem Ii

Front 1

Which muscles cause the eyes to move within the orbits?

Back 1

Extraocular

Front 2

Which muscles control pupillary size and accommodation?

Back 2

Internal ocular muscles

Front 3

The nuclear and infranuclear pathways involved which structures?

Back 3

brainstem nuclei of CN III, IV, and VI, the peripheral nerves of these nuceli, and eye movement muscles.

Front 4

Supranuclear pathways involve which structures?

Back 4

brainstem and forebrain circuits that control eye movements via connections with CN III, IV, and VI nuclei.

Front 5

Which six extraocular muscles are innervated by CN III, IV, VI?

Back 5

1.lateral rectus (abduction)
2.medial rectus (adduction)
3. superior rectus (elevation and intorsion)
4. inferior rectus (depression and extorsion)
5. superior oblique (depression and intorsion)
6. inferior oblique (elevation and extorsion)

Front 6

The ___ nerve innervates the extraocular muscles: medial rectus, superior rectus, inferior rectus, inferior oblique

Back 6

Oculomotor nerve (CN III)

Front 7

The ___ nerve innervates the superior oblique muscle.

Back 7

Trochlear nerve (CN IV)

Front 8

The ___ nerve innervates the lateral rectus.

Back 8

Abducens nerve (CN VI)

Front 9

The parasympathetic fibers controlling pupil constriction are vulnerable to compression by aneurysms particulalry originating from _______.

Back 9

Posterior communicating artery

Front 10

Trochlear nerves are the only nerves to exit the brainstem dorsally in a crossed fashion. They are susceptible to compression from _________ and ________from head trauma.

Back 10

cerebellar tumors; shear injury

Front 11

Abducens nerves are susceptible to downward traction injury produced by____.

Back 11

elevated intracranial pressure

Front 12

Mechanical problems, extraocular muscle dysfunction, neuromuscular junction dysfunction, and disorders of CN III, IV, and VI are primary causes of _____.

Back 12

diplopia (double vision)

Front 13

Monocular diplopia or polyopia (3 or more images) can be caused by _____ disease, disorders of _____ cortex, or _______, but NOT by _________.

Back 13

ophthalmological; visual; psychiatric conditions; eye movement abnormality

Front 14

_________ gaze results from extraocular muscle dysfunction and causes _________.

Back 14

Dysconjugate; diplopia

Front 15

Abnormal lateral deviation of one eye is called ___.

Back 15

Exotropia

Front 16

Abnormal medial deviation of one eye is called _____.

Back 16

Esotropia

Front 17

Abnormal vertical deviation of one eye is called_____.

Back 17

Hypertropia

Front 18

Mild weakness present with only one coveed eye is called _____.

Back 18

Phoria

Front 19

Oculomotor Palsy involving complete disruption of CN III is characterized by:

Back 19

1. paralysis of all extraocular muscles except lateral rectus and superior oblique
2. eye lies in "down and out" position
3. upper lid is closed b/c of levator palpebrae superior paralysis
4. pupil is dilated and responsive to light

Front 20

5 Common causes of oculomotor palsy include:

Back 20

diabetic neuropathy; head trauma from shearing; nerve compression from intracranial aneurysms (e.g Pcomm); nerve compression from medial temporal lobe herniation; and opthalmoplegic migraine in children

Front 21

Third nerve palsy raises high suspicion for _______.

Back 21

aneurysm; can cause a painful oculomotor palsy involving pupil.

Front 22

______________ involving CN IV produces depression and intorsion resulting in _____ diplopia.

Back 22

Trochlear palsy; vertical

Front 23

CN IV palsy is confirmed by what four steps?

Back 23

Bielschowsky 3 step test plus one step:
1.hypertropia of affected eye
2.worsening vertical diplopia when affected eye looks nasally
3.improving vertical diplopia with head tilt away from eye
4.vertical diplopia worsens with downgaze

Front 24

CN IV is most commonly injured cranial nerve in ____.

Back 24

head trauma b/c of its susceptibility to shear

Front 25

Four other casues of vertical diplopia include:

Back 25

1. extraocular muscle disorders
2.myasthenia gravis
3.lesions of the superior division of CNIII affecting superior rectus
4.skew deviation (vertical disparity in eye position of supranuclear origin)

Front 26

Abducens palsy of the ____cranial nerve produces ____ diplopia which can also be caused by______and disorders of extraoclar muscles from ________, _____, ________, or ________.

Back 26

VI; horizontal; myasthenia gravis; thyroid disease, tumors,inflammation or orbital trauma.

Front 27

CN VI is susceptible to injury from downward traction caused by ____.

Back 27

Intracranial Pressure

Front 28

Abducens palsy is an early sign of what conditions?

Back 28

1.supratentorial or infratentorial tumors
2.psudotumor cerebri
3.hydrocephalus
4.other intracranial lesions

Front 29

CN VI lesions often affect CN___fibers, cuasing _____facial weakness.

Back 29

VII; ipsilateral

Front 30

Pupils are controlled by which 2 pathways?

Back 30

1. parasympathetic
2. sympathetic

Front 31

Parasympathetic pathways involving pupil constriction are:

Back 31

1.light enters eye
2.retinal ganglion cells project to both optic tracts
3.brachium of superior colliculus
4.past LGN
5.pretectal area
6.Edinger-Westphal nucleus
7.ciliary ganglia via oculomotor nerves
8.pupillary constrictor muscles

Front 32

A light shone in one eye causes a ____ response in the same eye and a ____response in the other eye because information crosses_____ at multiple levels.

Back 32

direct; concensual; bilaterally

Front 33

The ____ response is another pathway for bilateral pupillary constriction and occurs when a visual object moves from __ to __.

Back 33

Acommodation; far to near

Front 34

Characteristics of the accommodation response include:

Back 34

1.pupillary constriction
2.accommodation of the lens ciliary muscle
3.convergence of the eyes

Front 35

Pupillary asymmetry is called___.

Back 35

anisocoria

Front 36

Oculomotor nerve lesions cause what pupillary abnormalities?

Back 36

1.impaired constriction causing unilateral dilated pupil
2.very large pupil ("blow pupil") when lesion is complete

Front 37

Horner's Syndrome is characterized by what triad of symptoms?

Back 37

1.ptosis (upper eyelid droop)
2.miosis(decreased pupillary size)
3.anhidrosis (decreased sweating of the ipsilateral face & neck)

Front 38

Horner's Syndrome is caused by________.

Back 38

loss of sympathetic innervation to the pupillary dilator muscle, causing impaired dilation of the pupil

Front 39

lesions anywhere in the ____ pathway can cause Horner's Syndrome.

Back 39

sympathetic

Front 40

Afferent pupillary defect is also known as _____.

Back 40

Marcus Gunn Pupil

Front 41

Afferent pupillary defect is characterized by________and _____.

Back 41

direct response to light in affected eye is decreased/absent; consensual response of affected eye to light in opposite eye is normal.

Front 42

Causes of afferent pupillary defect include:

Back 42

decreased sensitivity of affected eye to light from lesions of the optic nerve, retina, or eye

Front 43

Slight pupillary asymmetry (<.6mm) in 20% of the general population that may vary periodically is called____.

Back 43

benign (essential, physiological) anisocoria

Front 44

Pharmacological miosis and mydriasis can be caused by opiates which result in_____; barbituate overdose which causes____;and anticholinergic agents that cause_____.

Back 44

bilateral pinpoint pupils; bilateral small pupils; dilated pupils

Front 45

Midbrain Corectopia refers to lesions of the midbrain that can cause _______.

Back 45

pupillary abnormality where pupil assumes an irregular offcenter shape (rare)

Front 46

The following are all potential causes of ______:
-Horner's syndrome
-Oculomotor nerve palsy
-myasthenia gravis
-redundant sin folds from aging
-nondominant parietal lobe lesion
-dorsal lesions of the oculomotor nuclei affecting the central caudate nucleus
-voluntary eye closure

Back 46

Ptosis (drroping of the eyelid)

Front 47

Which muscles and cranial nerves are associated with eye opening?

Back 47

levator palpebrae superior (CN III), Muller's smooth muscle in upper eye lid (sympathetics); frontalis muscle (CN VIII)

Front 48

Which muscle and cranial nerve is involved with eye closure?

Back 48

orbicularis oculi muscle (CN VII)

Front 49

region where almost all nerves, arteries, and veins of the orbit converge before communicating with the intracranial cavity via the optic canal and superior orbital fissure

Back 49

orbital apex

Front 50

cavernous sinus syndrome, characterized by total ophthalmoplegia and a fixed, dilated pupil, involves which cranial nerves?

Back 50

CN III, IV,VI, V1

Front 51

Which type of lesion produced similar symptoms as complete lesion of the cavernous sinus, but may also involve CN II, resulting in visual loss?

Back 51

orbial apex lesion

Front 52

supranuclear circuits control which types of horizontal, vertical, and vergence eye movements?

Back 52

saccades (rapid eye movementsthat bring targets into field of view--only one that can be performed easily voluntarily)
smoot pursuit (slower eye movements, not under voluntary control, allow stable viewing of moving objects)
vergence (slower eye movements that maintain fused fixation by both eyes as targets move toward or away from viewer)
reflex eye movements (include optokinetic nystagmus and vestibulo-ocular reflex)

Front 53

rhythmic form of reflex eye movements made up of slow eye movements in one direction and interrupted by fast saccade like eye movements in opposite direction is called _____.

Back 53

nystagmus

Front 54

important horizontal gaze center that provides input from the cortex and other pathways to the abducens nucleus is called _____.

Back 54

paramediuan pontine reticular formation (PPRF)

Front 55

Name and describe five lesions affecting horizontal gaze.

Back 55

1. abducens nerve (impaired abduction of ipsilateral eye)
2. abducens nucleus (ipsilateral lateral gaze palsy in both eyes)
3. PPRF (ipsilateral lateral gaze palsy)
4.MLF (internuclear ophtalmoplegia-INO: eye ipsilateral to lesion does not fully adduct on attempted horizontal gaze, nystagmus in opposite eye; side of INO is same as side of MLF lesion)
5.MLF and adjacent abducens nucleus or PPRF (one and a half syndrome: ipsilateral INO plus ipsilateral lateral gaze palsy)

Front 56

MS plaques, pontine infarcts, MLF neoplasms are common causes of____.

Back 56

MLF lesions which cause INO (internuclear ophthalmoplegia)

Front 57

Large pontine lesions disrupt bilateral corticospinal tracts and abducens nuceli, eliminating body movements and horizontal eye movements are chacteristics of which syndrome? Sometimes vertical eye movement centers in the midbrain are spared, allowing communication entirely through vertical eye movements.

Back 57

Locked in syndrome.

Front 58

________ eye movements are generated by superior and inferior rectus and superior and inferior oblique muscles; brainstem controlling centers are located in the ____midbrain_____ and _____ area. _____portion mediates downgaze; ____ region mediates upgaze.

Back 58

vertical; rostral, reticular formation; ventral; dorsal

Front 59

Parinaud's syndrome, caused by pineal region tumors and hydrocephalus, is composed of what four components?

Back 59

1. Impaired vertical gaze (especially upgaze)
2. large, irregular pupils with light-near dissociation
3. eyelid abnormalities
4. impaired convergence and sometimes convergence-retraction nystagmus

Front 60

Descending cortical pathways go directly to the _____centers for horizontal, vertical or vergence eye movements or via relays in the _____ ____ _____.

Back 60

brainstem; midbrain superior colliculi

Front 61

Frontal eye fields in the forebrain also control eye movements. They lie at the junction between ____ ___ ___ and ___ ___; overlap ___ and ___ cortices which reflect roles in __ ___ __and ____ ___; generate saccades in ___ diretion via the ____.

Back 61

superior frontal sulcus, precentral sulcus; premotor and prefrontal; eye movement control, selective attention; contralateral, PPRF.

Front 62

___-___-____ cortex is responsible for smooth pursuit movements in the ____ direction via connections with the vestibular nuclei, cerebellum, and PPRF.

Back 62

parieto-occipital-temporal, ipsilateral

Front 63

cortical descending control of eye movements is heavily influenced by ____ inputs from the primary ___ cortex and ___association cortex.

Back 63

visual

Front 64

Subcortical ___ ____ also modulate eye movements.

Back 64

basal ganglia

Front 65

Cerebral hemisphere lesions normally impair eye movements in the ____ direction, causing a gaze preference ____ the side of the lesion;

Back 65

contralateral, toward

Front 66

cerebral hemisphere lesions are normally accompanied by weakness ____ to the cortical lesion, so the eyes look ___ the side of weakness

Back 66

contralateral, away from

Front 67

Wrong way eyes look ____ the side of weakness. Possible causes include: ___ in cortex, __lesions (thalamic hemorrhage) usually accompanied by deep coma, and ___.

Back 67

toward; seizure, large, lesions of the pontine basis and tegmentum

Front 68

Symptoms of oculomotor nerve palsy (CNIII) secondary to aneurysum include:

Back 68

left frontal and retro-orbital headaches, hx of left eye drifting to the left, diplopia with image from left eye above and to the right of image from the right eye; diplopia worse when looking to right; left eye with limited but not absent upgaze, downgaze, and adduction, and ptosis, and fixed dilated pupil

Front 69

Hx of diabetes, horizontal diplopia worse on left gaze, and incomplete abduction of left eye can be caused by what?

Back 69

isolated abducens nerve palsy caused by microvascular disease

Front 70

Symptoms of right hypertropia and vertical diplopia worse with downward and leftward gaze and worse with rightward head tilt can be associated with what dx?

Back 70

isolated right trochlear nerve palsy caused by idiopathy neuropathy of likely microvacular origin

Front 71

Name possible differental diagnoses of the follwing symptoms:on right gaze, left eye pain, limited adduction, horizontal diplopia with right image disappearing when left eye covered; on left gaze mild horizontal diplopia with left image disappearing when left eye covered; pain and erythema of left orbital conjunctiva

Back 71

infectious, inflammatory, neoplastic disorder, orbital myositis (orbital pseudotumor: uncommon inflammatory condition of the extraocular muscles

Front 72

Symptoms of Horner's syndrome caused by TBI or carotid dissection may include___?

Back 72

left ptosis, small reactive left pupil with decreased ciliospinal reflex, decreased left facial sweating

Front 73

Lethargy, rightward gaze preference, inability to move either eye past midline toward the left; right face, arm, and leg weakness; upgoing plantar response to the right can be caused by___ or ___.

Back 73

Wrong way eyes; infarct of the left pons

Front 74

Headaches, large pupils with minimal reaction to light but preserved reaction to accommodation (light-near-dissociation_; inabilty to look upward; lid reaction and convergence-retraction nystagmus can be caused by____.

Back 74

Parinaud's syndrome from pineal region tumor compressing the dorsal midbrain