Clinical Aspects of the Sensory and Motor Pathways Flashcards Preview

Neuroscience I Test 3 > Clinical Aspects of the Sensory and Motor Pathways > Flashcards

Flashcards in Clinical Aspects of the Sensory and Motor Pathways Deck (22):
1

lesion of the dorsal roots

-may diminish motor reflexes including muscle tonicity
-involvement of the dorsal roots in the sacral region results in atonic bladder and painless retention of urine
-also occurs with tabes dorsalis

2

if you cut the dorsal root fibers...

get dec tone and dec M spasticity
-cut degree of contracture of M
-input=output--if cut input to reflex arc, you diminish output

3

lesions of primary neurons in conscious sensory pathway

result in ipsilateral lesions

4

unilateral lesions of the posterior columns

-complete unilateral lesions of the posterior columns result in an ipsilateral loss of proprioception, 2 point tactile discrimination and vibratory sensations below to the level of the lesion

5

unilateral lesion of the fasciculus gracilis

-results in ipsilateral loss of proprioception, 2 pt tactile discrimination and vibratory sensations from the lower half of the body and lower extremity
-partial lesions result in a sensory dermatomal deficit corresponding to the affected region of the fasciculus gracilis

6

unilateral lesion of the fasciculus cuneatus

-results in ipsilateral loss of proprioception, 2 pt tactile discrimination, and vibratory sensations from the upper hand of the body and upper extremity
-partial lesions result in a sensory dermatomal deficit corresponding to the affected region of the fasciculus cuneatus

7

lesion of the lateral corticospinal tract

-results in ipsilateral spastic paralysis, hyperreflexia, hypertonia, Babinski sign, clonus, and disuse atrophy below the level of the lesion
-also occurs with destruction of assoc motor tracts in the lateral funiculus

8

lesion of the lateral reticulospinal tract

-transection of the SC above S2 interrupts the lateral reticulospinal tracts to the sacral autonomic nucleus
-pt is unable to voluntarily cold bladder so experience urinary retention
-after spinal shock, the bladder reflex may return without voluntary control, and pt will have automatic reflex voiding or a reflex bladder

9

unilateral lesion of the lateral spinothalamic tract

-result in contralateral loss of pain and temp sensation 2 sensory dermatomal segments BELOW the level of the lesion

10

lesions of secondary neurons in a conscious sensory pathway

contralateral deficits

11

lesion of the anterior white commissure

-results in bilateral loss of pain and temp sensations to the upper extremities (*yoke like anesthesia)

12

lesions of lower motor neurons in the anterior horn of the SC

-LMN paralysis results from the destruction of motor neurons or the axons of one or more of the cranial or spinal motor nuclei
-LMN paralysis is characterized by flaccid paralysis, areflexia, atonic, atrophy, and fasciculations

13

testing position sense

-with the pt's eyes closed, the examiner gently flexes and extends the pt's diner or toe
-pt should be able to indicate whether the digit is bent, straight, unchanged

14

testing vibratory sense

-pt should be able to discern vibrations from activated tuning fork when placed on medial malleolus or MCP joint

15

testing stereognosis and 2 point discrimination

-when placed upon palm or sole, pt should be able to distinguish the 2 blunt tips of open paper clip as being separate

16

poliomyelitis

-affects alpha motor neurons and LMN
-involves the motor neurons of the anterior horns and CN motor nuclei
-initially, there is severe inflammation, vasodilation, edema, macrophagic activity
-then, these neurons die and there is astrocytic gloss
-symptoms may subside and pt may completely recover or result in varying degrees of paresis or paralysis

17

Amyotrophic Lateral Sclerosis (ALS)

-cause is unknown, but may be due to defect in glutamate metabolism
-AKA Lou Gehrig's Dz
-onset avg is 66 yo
-death due to bulbar paralysis: virtual respiratory centers within an avg of 4 yrs of onset
-most common form involves:
-LMN: anterior horn cells, hypoglossal nucleus, nucleus ambiguus, facial motor nucleus
-UMN: chronic, progressive degeneration of corticospinal tracts
-ALS leads to LMN paresis and atrophy of the intrinsic Ms of the hands followed by arms and shoulder musculature
-pts may develop dysarthria, dysphagia, and paresis of tongue
-involvement of corticospinal tract leads to spastic paralysis, hyperreflexia, and Babinski sign
-NO SENSORY DEFICITS

18

anterior horn...

alpha motor neurons, LMN

19

anterior white commissure...

fast pain pathway

20

lateral spinothalamic tract...

pain and temp from contralateral side of body

21

lateral corticospinal tract...

UMN

22

posterior columns...

fasciculus cuneatus (not below T6)
fasciculus gracilis