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Flashcards in Images2 Deck (34)
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1
Q

Spinothalamic tract

(a) Synapses
(b) Decussations

A

Spinothalamic tract for pain/temp

(a) Synapses twices
- in dorsal horn
- at VPL of the thalamus
(b) Decussates across the anterior gray commisure 1-2 levels above where it enters the SC

2
Q

Where in the brainstem do each of the cranial nerves sit?

A

CN I and II don’t go thru the brainstem

CN III, IV = midbrain

-midbrain stroke can cause 3rd nerve palsy

CN V, VI, VII, VIII = pons

=> brainstem glioma around the pons can present w/ 6th nerve palsy

CN XI, X, XI, XII = medulla

3
Q

Describe the vascular territories of the following cross section

A
  • note little sliver of ACA on top, then large chunk MCA b/c we’re deep here
  • then inferiorly PCA
4
Q

Pt w/ visual field deficit in the RUQ, locate the lesion (be specific)

A

Lesion = Optic radiations/Meyer’s loops = axonal connections btwn the lateral geniculate nucleus of the thalamus and the primary visual cortex of the occipital lobe

RUQ visual field deficit = optic radiations in the temporal lobe on the left

  • superior quadrant affected 2/2 lesion of Meyer’s loops (temporal lobe)
  • inferior quadrant 2/2 lesion to superior optic radiation (parietal lobe)
5
Q

Locate the lesion

A

Left eye: mild ptosis w/ constricted pupil, also probably left sided anhidrosis = Horner’s syndrome 2/2 loss of sympathetic innervation to left side

Lesion of the superior cervical ganglion (houses the sympathetics)

-also can be 2/2 carotid artery dissection (or vertebral artery dissection = Wallenberg syndrome)

6
Q

Expected MRA finding in a pt w/ 3rd nerve palsy

A

B/c of where the CN III exits the brainstem, right under the PCOMM => CNIII gets compressed by PCOMM aneurysm

7
Q

Pt w/ the following MRI is likely to present w/ what visual complaint?

A

Pituitary pathology, possible etiologies adenoma, craniopharyngioma, etc

No matter what the etiology: getting compression of the optic nerve, causing bitemporal hemianopsia (loss of lateral fields of view)

8
Q

Corticospinal tract

(a) Synapses
(b) Decussates

A

(b) Decussates at the medullary pryamids
(a) Synapses in the anteiror horn of the spinal gray matter before learing

9
Q

Cuneate vs. gravile fasciculus

A

Both are dorsal column fibers

  • cuneate fasciculus carries fibers from the arms (lateral): lateral b/c added on as the tract ascends
  • gracile fasciculus carries fibers from the legs (medial)
10
Q

Occlusion of the anterior spinal artery

Effect on each of the three spinal cord pathways

A
  • weakness bilaterally (b/c hitting both lateral corticospinal tracts)
  • loss of pain and temp bilaterally (b/c hitting both spinothalamic tracts)
  • preservation of proprioception and vibration b/l (b/c dorsal columns not invovled
11
Q

When pt looks to the right he cannot adduct his left eye, and there is abducting nysagmus of the right eye

-convergence preserved

Locate the lesion

A

Lesion of the medial longitudinal fasciculus (MLF) which connects CNIII and CNVI to allow for conjugate gaze

Conjugate gaze = simultaneous activation of medial and lateral rectus muscles to allow eyes to look in one direct simultaneously

12
Q

Cavernous sinus

(a) Name 2 things in it besides cranial nerves
(b) What sits on top?
(b) Underneath?

A

Cavernous sinus

(a) Internal carotid artery and the pitutiary galnd
(b) Right on top sits the optic chiams
(c) Sinuses are right underneath

13
Q

Differentiate the side effect by peripheral vs. central seventh nerve palsy

A

Central 7th = lesion of the motor pathway above the facial nucleus (supranuclear lesion)

  • spares upper facial muscles, so you can move your forehead
  • causes weakness of lower part of the phase CONTRALATERAL to the lesion

Peripheral 7th = lesion of the facial nucleus in the pons or the facial nerve itself

-weakness of the entire face IPSILATERAL to the lesion

14
Q

Dorsal Column/Medial Lemniscus pathway

(a) Synapses
(b) Decussates

A

Dorsal columns for proprioception and fine touch

(a) Synapses twices
- in lower medulla just before decussating
- in VPL of thalamus
(b) Decussates in lower medulla forming the medial lemniscus throughout the brainstem

15
Q

Initial sign of posterior communicating artery anurysm

A

Ipsilateral dilated pupil

-Compressive lesion (parasym fibers are on the outside) so parasymp fibers are lost before the EOM are affected

16
Q

Pt p/w bitemporal hemianopsia and CT showing pitutiary mass w/ calcifications

(a) Dx
(b) Mechanism of visual complaints

A

(a) Dx = craniopharyngioma
- calcified on CT
(b) Compression on optic nerve

17
Q

Describe Brown-Sequard syndrome

A
  • weakness ipsilateral to the lesion
  • loss of proprioception/vibration on same side of the lesion
  • loss of pain/temp opposite the lesion
18
Q

Describe finding’s of Bell’s palsy

A

Unilateral facial paralysis

  • can’t close eye on affected side
  • can’t smile (mouth drooped)
  • smoothing of forehead (can’t raise eyebrown muscles)
  • loss of nasolabial fold

Also may find: dry eyes, facial twitching, dry mouth, impaired taste

19
Q

Pt p/w hearing difficulties in the left ear

  • Weber’s: hears tuning fork louder in left ear
  • when holding tuning fork next to each ear: hears better in the right ear

Dx

A

Dx = conductive hearing loss on the left

  • air conduction normal on right => sounds louder when tuning fork just held next to ear
  • Weber: if louder in affected ear = conductive hearing loss
20
Q
A
21
Q

What is the thalamic nuclei responsible for vision?

A

Lateral geniculate nucleus of the thalamus

= relay center for the visual pathway

-connects optic nerve to the occipital lobe by sending axons thru the optic radiations

22
Q

What is the tract of Lissauer?

A

Gray matter tract of entering spinothalamic fibers
-right where the spinothalamic fibers enter

23
Q

Pineal gland

(a) Function
(b) appearance on CT
(c) Most common pineal-region tumor

A

Pineal gland

(a) Secretes melatonin to regulate sleep/wake cycle
- stimulated by darkness, inhibited by light
(b) Physiologically calcified on CT
(c) Germinomas = most common pineal-region tumors

Pinealomas = primary pineal tumors, often clinically silent until large enough to compress vertical gaze center of the midbrain (=> vertical gaze palsy)

24
Q

Diagnostic test for BPPV

A

Dix-Hallpike maneuver: basically move the pt (w/ head tilted at 45 degrees) from seated to supine and see if the nystagmus is in the same direction as gravity

25
Q

Label the main parts of this midbrain cross section

A
  • see CN III leaving out the center
  • red nucleus b/l
  • substantia nigra (Parkinsonism…)
  • cerebral peduncle superiorly
26
Q

Describe the manifestations of central cord syndrome due to a syrinx in the cervical spine

A

Loss of pain/temp in ‘shawl distribution’ (aka b/l) b/c hitting the spinothalmic tract as it’s decussating

-can get weakness if the anterior horns are affected

27
Q

(a) After stroke affecting the left frontal lobe, which way will eyes deviate?
(b) Seizure focus originating in left frontal lobe, which way will eyes deviate?

A

(a) Eyes deviate left
- towards the lesion b/c right eye fields are acting unopposed (to deviate eyes left)

(b) Eyes deviate right, eyes deviate away from seizure focus

Frontal eye fields deviate eyes in the opposite direction

28
Q

Describe the path CN III takes to emerge from the brainstem

A

CN III runs under the PCOMM then right between the PCA (posterior cerebral) and superior cerebellar artery to exit the brainstem

29
Q

45 yo M can’t move left eye

  • left fixed, dilated pupil w/ ptosis
  • numb on upper and middle face

Locate the lesion

A

Lesion of the cavernous sinus: only place where CN III, IV, VI, V1, V2 all can be hit at once

CN III, IV, VI loss = loss of EOM, dilated pupil (loss of parasymps from CN III), ptosis b/c CN III innervates levator palpebrae superioris
-facial numbness from V1/V2

30
Q

Pt p/w upgaze paralysis 2/2 compression of the vertical gaze center in the midbrain (circled in red)

What type of tumor?

A

Tumor of the pineal gland (pinealoma)
-often silent until compresses midbrain enough to cause vertical upgaze restriction

31
Q

Maneuvers for tx of BPPV

A

Epley maneuvers

-series of positional changes to help reposition otolithic material in the posterior semicircular canal

32
Q

Differentiate Rinne and Weber test

A

Weber test: tuning fork on forehead, sound should be the same in both ears

  • conductive hearing loss: sounds louder in affected ear
  • sensorineural hearing loss: sound louder in unaffected ear

Rinne test: Press tuning fork against the mastoid, then hold just next to the ear

  • louder next to ear than on bone = normal (air conduction better than bone conduction)
  • louder on bone than next to ear = conductive hearing loss
33
Q

Locate the lesion that causes

(a) Monocular blindness
(b) Homonymous hemianopsia
(c) Homonymous hemianopsia w/ macular sparing
(d) Bitemporal hemianopsia
(e) Upper quadrantanopia

A
34
Q

Describe the venous drainage system of the brain

A
  • Inferior sagittal and great cerebral vein (of Galen) drain into straight sinus
  • Superior sagittal sinus meets straight sinus forming the confluence of sinuses that continues downwards as the transverse sinus
  • cavernous sinus (whcih the opthalmic veins drain into) drains into the transverse sinus forming the sigmoid sinus
  • sigmoid sinus then continues down into internal jugular vein