upper and lower motor neuron lession Flashcards
what are the signs of motor neuron lesions?
paresis/paralaysis
muscle atrophy
involuntary muscle contractions
abnormal tone
abnormal reflexes
muscle hyper-stiffness
disturbances of movement efficiency and speed
Impaired postural control
what are the signs and symptoms of central nervous system?
brain and spinal cord
increased tone
a. spasisity
b. rigidity
c. clonus/babinski
increased deep tendon reflexes
atrophy over a prolonged period of time
what are the signs and symptoms of peripheral nervous signs and symptoms
-outgoing/input “wires”
decreased tone/flaccidity
no or diminished DTR
Quick atrophy
what is normal muscle tone
Palpable stiffness (stretch resistance) in resting muscles
what is low muscle tone?
= hypotonia or flaccidity
LMN lesions
Acute UMN lesions (usually temporary)
Developmental disorders
what is high muscle tone?
=hypertonia
chronic UMN lesions
some basal ganglia disorders may be specific or rigid
what is the brain
the mediator
what is the spinal cord
router
what are the peripheral nerves in the system
the wires sending signals
no dampening of signals would mean?
increased tone, spasticity, rigidity, and a cycling of stretch reflexes
what is paresis
a decrease in the amount of movement or strength
hemi-
one side of the body
para-
caudal half
tetra- all limbs
what is plegia paralysis
a complete loss of the ability to move
hemi
para
tetra (used to be quad)
what is atrophy
loss of muscle bulk
Disuse atrophy
due to disuse
Neurogenic atrophy:
due to nervous system damage
Denervated muscles demonstrate the most severe atrophy; even small, partial innervation will maintain some muscle fibers’ health
LMN damage results in rapid atrophy due to changes in the pattern of protein production
UMN damage
Muscles still receive stimulation from intact LMNs and atrophy is slower
what are the types of involuntary muscle contractions
muscle spasms
cramps
myoclonous
fasciculations
fibrillations
abnormal movements due to basal ganglia dysfunction
what is a muscle spasm
sudden involuntary contractions of muscles
what is a cramp?
particularly severe and painful muscle spasms
what is a myoclonus
Brief, involuntary contractions of a muscle or group of muscles
May occur in a healthy nervous system or be signs of pathology (dependent on context)
what is a fasciculation
Quick twitches of single motor unit muscle fibers that are visible on the surface of the skin
what is a filibration
Brief contractions of single muscle fibers not visible on the surface of the skin
May occur with UMN or LMN disorders
what is spinal/cerebral shock?
Occurs when UMN lesion disrupts descending motor command and results in a temporary inactivity of the LMNs
Cannot elicit stretch reflexes, muscles are hypotonic
After recovery, interneurons and LMNs become active again but activity is no longer modulated by UMNs
Often in the months after UMN lesion muscle tone and stiffness increases within causing excessive resistance to muscle stretch
53-year-old female found collapsed in the street and brought to hospital where she remains unconscious for 3 days. Upon regaining consciousness the following is found:
Face is flushed on (R) side
Spastic paralysis of (R) side of body with some movement sparing at the (R) shoulder
Exaggerated DTRs in (R) extremities
Analgesia and thermal anesthesia on the (L) inferior to dermatome C8
Analgesia and thermal anesthesia of dermatome C7 on (R)
(R) sided miosis, enophthalmosis and partial ptosis
Is this a upper motor neuron lesion or a lower motor neuron lesion?
What traits are you seeing:
- flushing
-paralysis on R
-exaggerated DTRs on R
-weird sensory:
- L analgesia below C8
- R analgesia below C7
- R sided eye and facial symptoms
what is the pathology of a motor neuron lesion?
vascular event= stroke
mostly affecting the anterolateral spinal cord
branches of the anterior spinal artery supplying the r anterior /lateral cord and R sns ganglia
What would be the difference between a c7 and c8 sensory loss
Injury at ~C7 on (R)
Anterolateral spinothalamic tract
Discriminative pain and temperature
Fibers cross at spinal cord entrance
Therefore:
Impacting C7 fibers crossing anteriorly and those below after the decussation
C7 (R) & below C8 (L)
tell me about the autonomic nervous system
Outputs
Thoracolumbar – Sympathetic
Craniosacral - Parasympathetic
Innervation of visceral muscles and glands
Cardiac muscles, lungs, secretory glands
GI tract - large portions of its innervation is localized
Parasympathetic Nervous System
Homeostasis (Rest and repose #chillin’)
Sympathetic Nervous System
Arousal (Fight or flight)
tell me about the sympathetic nervous system
Cell bodies of the preganglionic neurons are located in the thoracic intermediolateral gray horn.
So, while the sympathetic paravertebral ganglia are physically intact, their neurons are impacted by the site of lesion because the artery involved also supplies the SNS ganglia.
See Lundy-Ekman
