S3: Pathway Lesions and SX Flashcards Preview

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Flashcards in S3: Pathway Lesions and SX Deck (20)

Ipislateral loss of epicritic sense can occur from X of the

Dorsal column/lemniscal sys.

1. dorsal root axons

2. gracile or cuneate fasiculus (spinal cord)

3. gracile or cuneate nuceli (medulla)


Contralateral loss of epicritic sense can occur from X of the

1. medial lemniscus going up the medulla, pons, midbrain to thalamus

2. VPL in thalamus

3. post central gyrus


what does loss of epicritic sense include?

loss of

1. sterogenesis (cant recognize tactile shapes in hand)

2. position sense - can lead to shuffling gait, reaching inaccuracies

3. loss of vibration - insesntive to high frequency stimulation

3. simpe touch intact but sensitivity decreased



why is EPICRITIC information coming into the spinal cord suspectible to injury?

it comes in as large diameter dorsal root axons -- vulnerable to insult from ischemia, toxicity, bacteria, etc


so: early sx of peripheral nerve disease shows as epicritic



ipsilateral loss of protopathic informaiton is seen witn


1. dorsal root axons

2. lissaeurs tract or dorsolateral fasciulus

3. dorsal horn


spinocerebellar carries ___ information from the ___

proprioceptive (muscle and joint position) from the trunk and limbs


ipislateral loss of propathic from head and neck

caused by X of 

1. spinal tract of CN 5

2. spinal n. of 5 in the medull


contralateral loss of propathic from head and neck

caused by X of 

1. after the spinal nulceus in the medulla (where it crosses) so a pons or midbrain region

2. in the vpm 


loss of proprocpetive from face on the same side can be due to

X trigmeminal nerve

X mescephalic nucleus of 5

X menscephalic tract of CN 5

X motor n. of 5 in the pons 

X cerebellum


loss of chewing on the same side can be caused by

 X motor n. of 5 in the pons

X trigeminal nerve 


corticobulblar controls hypoglossal cranial nerve ncueli mostly



corticobulblar controls facial  cranial nerve ncueli mostly



  The bilateral projections from the surviving CB can sustain considerable movement on both sides of the patient


Usually only the___ and ___ are affected by a unilateral CB lesion

tongue and face (CN 7)


damage to the corticospinal in the brainstem therefore impairs movement mainly on the ____ side of the body. 



since mostly lateral corticopsinal which crosses and the pyrmida decessations


unilateral patholgoy of the corticobulbar tract sx

will weaken movement of the head and neck opposite of the X

does not significantly weakend since most cn actually get bilateral input from CB


damage to lateralc orticiospinal tract occurs with

X to the tract below the pyramids decussations in the medulla


In the few surgical case studies of isolated CS damage (lesion of the medullary pyramid), the sx were

modest: temporary weakness, permanent Babinski’s sign, and permanent loss of independent finger movements.


mostly the pyramidal tracts are damaged with the brainstem tracts so sx area outright pralysis


Frontal lobe lesions often cause ___ 

severe paralysis because the precentral (motor) and premotor areas of cortex contribute to both direct and indirect motor pathways


damage to a Brainstem-spinal pathways at the level of the medulla wiill cause

problems with movement on the opposite side of the body


damage to a Brainstem-spinal pathways at the level of the spinal caord wiill cause

problems with mvoement on the same side of the body