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24 Cards in this Set

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Name the spinal tract responsible for motor?
corticospinal tract
how many neurons are needed in the motor tract and where are their cell bodies located?
2 - upper and lower motor neuron; LMN connects the muscle to the LMN in the spinal cord; the UMN goes from that area in the spinal cord, travels up the spinal cord and crosses in the caudal medulla and connect in the precentral (motor) gyrus.
How can you tell the difference in an UMN and LMN lesion?
look at the reflex - LMN (absent reflex, no Babinski, flaccid paralysis) UMN (hyperreflexive, Babinski sign (extension of toes), spastic paralysis)
Name the 2 sensory tracts?
1)Dorsal Column - Medial Lemniscal System - position sense, vibration, pressure 2)Anterolateral (spinothalamic) system - pain and temperature
How many neurons are needed in the sensory system tracts and where are their cell bodies?
3 neurons: 1st order-dorsal root ganglion; 2nd order - in the spinal cord or brainstem (always crosses the midline) now called the medial leminiscus; 3rd-in the Thalamus and goes to the postcentral (sensory) gyrus
In the dorsal columns, name the tracts and what they are responsible for?
fasciculus gracilis - sensory lower extremities; fasciculus cuneatus - sensory upper extremities.
What clinical exam could you do to rule out or rule in dorsal column lesion?
Romberg sign - (sways with eyes closed)position sense and/or vibrating tuning fork; if it were a cerebellar disease - pt would sway with eyes open
What system is responsible for pain and temperature?
anterolateral (spinothalamic tract) system
Explain the organization of the cell bodies in regard to decussation in the pain and temp. sensory tracts.
the anterolateral system is different from others because as soon as the 1st order neuron enters the spinal cord it synapses with the 2nd order cell body; this then immediately decussates and runs up the spinal cord through the medulla and into the cortex as the spinothalamic tract. THus, it only decussates after it immediately enters the spinal cord.
If a person's right side has lost pain and temperature sensation, where is the lesion most likely located?
since the axons cross immediately upon entering the spinal cord; the lesion will be on the left side of the spinal cord.
where in the spinal cord is the spinothalamic tract located?
2nd order neurons cross near the ventral white commisure (near central canal); the spinothalamic tract is in the ventro-lateral position up the spinal cord
What is the spinocerebellar tract for and what would happen if it were lesioned at any level?
unconscious proprioceptive input from muscle spindles to the cerebellum, involved in lower extremity movement; helps monitor and modulate movements; if it were lesioned, there would be ipsilateral ataxia since the DORSAL spinocerebellar tracts don't cross
WHat hereditary disease involves degeneration of the spinocerebellar pathways?
Friedreich ataxia - gait ataxia and romberg sign
what connects lower motor neurons(in the grey matter) to the corticospinal tract (white matter) at each segment level?
interneurons
How does the ventral spinocerebellar tract differ from the dorsal spinocerebellar tract?
the ventral decussates directly after entering and ascends lateral to the lateral spinothalamic tract. It gives rise to axons that enter the cerebellum via the superior cerebellar peduncle. It decussates, the dorsal spinocerebellar tract does NOT.
What test will be difficult to do if there is a lesion in the spinocerebellar tract?
heel-to-shin test
At what segments are the lateral horns found?
T1-L2
How would a polio patient present?
since polio destroys LMN cell bodies, see: 1. flaccid paralysis, 2. muscle atrophy, 3. fasciculations, 4. areflexia
Amyotrophic lateral sclerosis is usually a destruction of the cervical enlargement that causes both LMN and UMN problems. Since the lesion is in the cervical spinal cord how would a patient present?
(amyotrophic - the LMN from the ventral horn cause flaccid paralysis in the upper limbs with hand muscle atrophy) the lateral sclerosis part refers to the destruction of the corticospinal tract (UMN)- this causes spastic paralysis in the lower limbs. also see increased tone and reflexes
This neuro disease is caused by neurosyphillus and causess destruction of large sensory fibers in the dorsal columns.
Tabes dorsalis - 3 Ps: Pain, Paresthias, Polyuria
If there is an anterior spinal occlusion, how would a patient present?
only dorsal columns are spared - lose the spinothalamic (pain and temp), corticospinal (motor) - Anterior spinal artery supplies anterior 2/3 of the spinal column
Explain this demyelinating disease. Get bilateral loss of sensory touch and vibration, gait ataxia, and spastic weakness.
Subacute Combined degeneration. It is caused by lack of either B-12, pernicious anemia (lack of intrinsic factor) or possibly AIDS. afffects dorsal columns, spinocerebellar tracts, and corticospinal tracts (UMN).
Explain how a pt would present that has a syrinx in the cervical spinal cord.
syringomyelia is due to a cavitation (usually of the cervical sc) around the central canal - since the ventral commissure is right there, it affects the spinothalmic tract since it decussates at the ventral commissure. this means a pt would present with bilateral loss of pain and temperature at the level of the lesion and as the dz progresses, it eventually compresses the ventral horn cells (compresses LMN) and would cause flaccid paralysis and atrophy)
How would a pt present with a hemisection in a lesion from below T1? what is this syndrome called?
Brown-Sequard syndrome - hemisection - 2 ipsilateral (corticospinal - paresis and dorsal columns - loss of position and vibration) and 1 contralateral - spinothalamic - pain and temperature); if the lesion is above T1: get Ipsilateral Horner Syndrome: anhydrosis, ptosis, miosis