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When do you only get lower motor neuron symptoms?

what are lower motor neuron symptoms?

where you have lower motor neuron damage

fasciculations, paralysis, atrophy


Motor tracts originate where?

in the cortex and brainstem


what is the only tract that originates in the cortex?


costicospinal tract


all other UMN tracts except the corticospinal originate where?

these tracts are called?

in the brainstem (infratentorial)

extrapyramidal UMN tracts


What are the descending tracts?


extrapyramidal UMN tracts


what are the extrapyramidal UMN tracts?

  1. Reticulospinal
  2. Tectospinal
  3. Rubrospinal
  4. Vestibulospinal
  5. Olivospinal


What does the Reticulospinal tract do?

voluntary and reflex movements via modulation of motor neurons in anterior horn.


(there are two reticulospinal, lateral and medial)


What does the Tectospinal tract do?

Reflex postural movements in respinse to visual stimuli

(like when there is a flash of light and you look at where it came from)


What does the Rubrospinal tract do?

inhibits extensors muscles,

stimualtes flexor muscles


what is the olivospinal do?

involved in movement of muscles


what is the Vestibulospinal?

  • stimulates extensors
  • inhibits flexors
  • involved in postural control and balance


(there are two vestibulospinal, lateral and medial, see vestibulospinal slide).



where does the lateral corticospinal descend through?

What about the anterior corticospinal?

Lateral: descends through brain ipsilaterally, then crosses and descends contralaterally in cord.


Anterior: descends ipsilaterally all the way to the cord, then innervates bilaterally.


what does the corticospinal tract do?

Voluntary, discrete (FINE!), skilled motor movements. 

(gives you the ability to make movements voluntarily  specific) 


(There are two corticospinal, lateral and anterior, see later).



where does the corticospinal tract come from?


Where does the corticospinal tract descend through?

is derived from precentral gyrus, postcentral gyrus, and premotor cortex.


descends through the posterior limb of the internal




What will the Lateral Corticospinal Tract activate?

 the contralateral distal musculature.


The corticospinal tract is actually composed of axons

from what parts of the brain?

precentral, postcentral, and premotor cortex


what are the Corticospinal Tract lesion symptoms?


  1. Paresis (hemiparesis)
  2. Babinski sign ‘present’
  3. Hoffman’s sign present: you flick 1 finger, the others close to it also flinch (not normal)
  4. Abdominal reflex absent
  5. Cremasteric reflex absent
  6. Spasticity, which is hyper-
  7. Reflexia of DTR’s, clonus, and
  8. Increased muscle tone (rigidity)


A stroke/lesion above the brainstem only affects which tract?


corticospinal tract


when there is damage to the corticospinal tract in the spinal cord, the symptoms are on which side?



The extrapyramidal tracts take care of what?

gross voluntary body movement


The reticulospinal tract has 2 parts, what are they?

how does each descend and what is its target?


Medial (pontine): it descends ipsilateral and innervates the extensors

Lateral (medullary): it descends ipsilateral and innervates the flexors


when do you use the Bing test and what is it?

bing test is another way of testing babinski sign by tapping on top of the foot in ppl who have big calluses on the foot


what is the function of the reticulospinal tract?

to inhibit reflex contractions, so that only noxious (painful) stimuli can illicit a flexor reflex.



Reticulospinal tract damage can result in what?

in flexor reflexes to innocuous stimuli (i.e. a light 

touch to someone’s hand and the pain withdrawal

response occurs).


What does the tectospinal tract do?

 we respond reflexively to motion or light.  Motion in periphery of vision, our eyes ‘jump’ to it.  Since the head and eyes are turning, the body needs to make reflex postural adjustments, and tectospinal is involved

in that.


damage to the rubrospinal tract will show up as what?

ataxia lack of coordination (especially if its a the red nucleus)


what is the vestibulospinal tract involved in?

in balance


what are the 2 divisions of the vestibulospinal tract?

what does each do?

Lateral: adjusts body posture (ispilateral only)


Medial: adjusts head posture (bilaterally)


tectospinal, medial and lateral vestibular, reticulospinal and anterior corticospinal tracts descend how?

how are they known?

they are collectively involved in what?

Lateral corticospinal and rubrospinal are involved in what? how are they known?


medial tracts

in reflex postural adjustments and balance.

 limb movements.

the lateral tracts



What are the Differences Between CST lesion and Extrapyramidal UMN Lesions?

Babinski, Hoffman’s, loss of abdominal and

cremasteric reflexes are CST alone. 


CST lesion and Extrapyramidal UMN Lesions will both present with what?

Weakness/paralysis/’paresis’ present for both.

Spasticity (with its components) present for both.



What are the Lower Motor Neuron Symptoms?

  1. Flaccid paralysis
  2. Atrophy of muscles
  3. Loss of reflexes
  4. Muscular fasciculation (muscle ‘twitches’ seen during slow destruction of LMN’s, like ALS)
  5. Muscular contracture (shortening of muscles)
  6. Reaction of degeneration (decreased response of muscle to electrical stimulation)


Give 2 examples of LMN

  1. Cranial nerve motor neurons
  2. Spinal cord motor neurons


LMN symptoms occur ONLY where?

at the level of the lesion


UMN symptoms would only be seen where?

below the level of the lesion.


What is Spinal Shock Syndrome?

how long does it last?

regeneration of nerves in this disease as part of recovery will result in what symptoms afterwards?


  • Occurs after major damage to the spinal cord.
  • Cord functions below the lesion are lost or depressed
  • less than 24 hrs-->weeks


  • Subsequent recovery (as ‘shock’ wears off) of neurons below the transection/damage results in spasticity, exaggerated reflexes, etc.


Complete cord transection will result in what sensory symptoms?


Complete cord transection will result in what motor symptoms?

Sensory: Bilateral loss of all sensation at and below the lesion.


Motor: Bilateral LMN paralysis at level of lesion, with muscle atrophy. Bilateral UMN signs below lesion.

(including Babinski, etc.).


Why does Anterior Cord Syndrome happen?

what gets damaged?

Anterior Cord syndrome will have what motor symptoms?

Anterior Cord syndrome will have what sensory symptoms?

  • Occlusion of the anterior spinal artery.
  • Anterior horns, some extrapyramidal tracts, and spinothalamic tracts damaged

Motor: Bilateral LMN symptoms at lesion. Bilateral UMN symptoms below the lesion, but NOT Babinski, or loss of abdominal or cremasteric (CST not damaged).


Sensory:  Bilateral loss of pain, temperature and light touch (spinothalamic tracts) at/below level of lesion.

Propioceptive loss (maybe), spinocerebellar tracts.


Why does Central Cord Syndrome happen?

What motor symptoms can be seen with Central Cord Syndrome?

What sensory symptoms can be seen with Central Cord Syndrome?


Occurs after hyperextension injury in an individual with long-standing cervical spondylosis.


Bilateral LMN symptoms. Bilateral UMN paralysis with

‘sacral sparing’ (remember the somatotopic organization).


Bilateral loss of pain, temperature and light touch, also with ‘sacral sparing’.Dorsal column symptoms may be present.


What motor symptoms can be seen in Brown-Sequard Syndrome?

What sensory symptoms can be seen in Brown-Sequard Syndrome?

  • Ipsilateral LMN symptoms at level of lesion. Ipsilateral spastic paralysis, Babinksi, hyperreflexia, below level of lesion.
  • Ipsilateral loss of two-point discrimination, vibratory and proprioceptive senses (dorsal column). Contralateral loss of pain, temperature, touch, 1-2 segments below the lesion (spinothalamic). Complete sensory loss, ipsilateral, at the level of lesion.


in poliomyelitis, we will see what type of damage?

LMN only


what type of damage will we see in ALS?

Symptoms of both LMN and UMN damage are present.


Identify which of these corresponds to Subacute combined degeneration. 

Also, what is this disease?


degeneration of Dorsal columns and lateral corticospinal tracts.


Identify which of these corresponds to Familial Spastic Paraparesis 

Also, what is affected in this disease?


damage to all corticospinal tracts.


Identify which of these corresponds to Spinocerebellar degeneration.

Also, what is affected in this disease?

C- image


Dorsal columns, corticospinal and spinocerebellar tracts.


what causes Subacute combined degeneration?

What symptoms can be seen in this?

What is happening physiologically in this disease?

Occurs most frequently where?

Caused by pernicious anemia, B12 deficiency.


Symptoms include paresthesias, leg stiffness, weakness, lethargy, fatigue, ataxia.


Results in degeneration of myelin and eventually the neurons.

The spinal cord


Spinocerebellar degeneration has 2 diseases subdived, what are these?

what symptoms do we see in each?

when is the onset for each?

  1. Friedreich’s ataxia:
  • onset at 5-15yrs

  • Muscle weakness and ataxia in arms and legs. Vision impairment, hearing loss. Slurred speech.  Aggressive scoliosis (curvature of the spine). Diabetes mellitus or carbohydrate intolerance. Enlarged heart

    2.  Machado-Joseph disease

  •  onset at 15-40yrs

  • Weakness in the arms and legs. Spasticity. Staggering, lurching gait, often mistaken for drunkenness. Difficulty with speech and swallowing. Nystagmus, diplopia, polyuria.


what sinal cord syndrome is this?


what sinal cord syndrome is this?


what spinal cord syndrome is this?


what spinal cord syndrome is this?


what spinal cord syndrome is this?


what spinal cord syndrome is this?


What is spastic bladder? (what do you see symptomwise)

Why does it  happen?

Damage above T12.  Bladder functions at segmental level without control from higher centers. Urination is involuntary, frequent and caused by spasms in the lower limbs. The sensation of fullness is lacking. 



What do you see in atonic bladder?

Why does it happen?