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Flashcards in Spinal Cord Disorders Deck (29)

When are LMN signs seen?

They are found in a limb if some of its muscles are innervated by anterior horn cells (lower motor neurons) are affected at the level of the spinal cord lesion.


When are UMN signs seen?

They are found in a limb if a more rostral spinal cord lesion affects the corticospinal tract (upper motor neurons) descending to the anterior horn cells which innervate the muscles in that limb.


Weakness and Atrophy in UMN Lesion

More diffuse, severe weakness with relatively mild atrophy


Weakness and Atrophy in LMN Lesion

More focal, milder weakness with severe atrophy


Are fasciculations seen in UMN, or LMN lesions?

LMN lesions


What happens to the tonality in UMN lesions?

Increased - spasticity


What happens to the tonality in LMN lesions?



What lesions increase reflexes?

UMN lesions


What lesions may have clonus?

UMN lesions


What lesions may have a Babinski sign?

UMN lesions


What can cause radicular pain?

- Dorsal Root Inflammation
- Compression


What side is there a pain and temperature deficit with a lesion in the STT?

Contralateral Side


What side are position sense and vibration deficits seen on with a lesion in the DCP?

Ispsilateral Side


What does sacral sparing indicate about a lesion?

It is intramedullary


What does sensory loss to a particular level or in the sacral area indicate about a lesion?

It is extramedullary


Transverse Myelopathy

A complete or nearly complete lesion encompassing the cross-sectional extent or breadth of the spinal cord at one, or a few adjacent, levels.


What is spinal shock?

The expected upper motor neuron signs only gradually emerge weeks to even months later after acute trauma.


Brown-Sequard Syndrome

A lesion affecting approximately the left or right half of the spinal cord cross- section at one level


What are the signs of a Brown-Sequard lesion?

Involvement of the spinothalamic tract produces a contralateral deficit to pain and temperature sensation, since spinothalamic sensory fibers decussate within the spinal cord, and then continue their ascending pathway. Involvement of the dorsal or posterior columns produces an ipsilateral deficit of vibration and position sense, since these sensory fibers ascend up the same side of the spinal cord, only decussating later in the medulla.



Syringomyelia refers to a spinal cord lesion from a syrinx, or cavity, within or near the center of the spinal cord. It is thus an intramedullary lesion, arising from within the spinal cord itself, and primarily affects the gray matter there.



Within or outside of the spinal cord


What are the sensory deficits seen in syringomyelia?

Suspended sensory level with sacral sparing. "Shawl" loss of pain and temperature with preservation of vibration and position sense.


What are the sensory defects in Anterior Spinal Artery Occlusion?

- Thoracic level of sensory loss, without sacral sparing, to pain and temperature.
- Since the posterior or dorsal columns are preserved, vibration and position sense remain normal.


What is the common cause of posterolateral syndrome?

Vitamin B12 deficiency


What are the deficiencies seen in posterolateral syndrome?

Vibration and position sense are reduced or lost in the lower limbs, leading to unsteadiness and falling if the patient stands or walks in the dark, or with eyes closed. This is further exacerbated by a spastic paraparesis from involvement of the corticospinal tract. Pain and temperature sensation are not affected by this spinal cord syndrome


Amyotrophic Lateral Sclerosis

ALS is a degenerative disease where upper and lower motor neurons are selectively and progressively destroyed, for unknown reasons.


What are the neural deficits seen in ALS?

- Sensory pathways are not affected, bowel and bladder functions remain normal
- Fasciculations
- Diffuse weakness with UMN and LMN signs progresses without obvious cause


Tabes Dorsalis

Lumbosacral dorsal roots become infected and inflamed, producing severe radicular pains in the lower limbs, described as lightning, electrical, or shocklike.


What are the deficits seen in tabes dorsalis?

The dorsal or posterior columns secondarily degenerate, so impairment of vibration and position sense in the lower limbs is noted. Eventually, most sensory fibers degenerate at these dorsal roots, creating loss of all sensation in the lower limbs, where reflexes are lost since the afferent reflex arcs are disrupted.

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