upper and lower motor neuron lession

Question 1

what are the signs of motor neuron lesions?

Answer 1

paresis/paralaysis
muscle atrophy
involuntary muscle contractions
abnormal tone
abnormal reflexes
muscle hyper-stiffness
disturbances of movement efficiency and speed
Impaired postural control

Question 2

what are the signs and symptoms of central nervous system?

Answer 2

brain and spinal cord
increased tone
a. spasisity
b. rigidity
c. clonus/babinski
increased deep tendon reflexes
atrophy over a prolonged period of time

Question 3

what are the signs and symptoms of peripheral nervous signs and symptoms

Answer 3

-outgoing/input “wires”
decreased tone/flaccidity
no or diminished DTR
Quick atrophy

Question 5

what is normal muscle tone

Answer 5

Palpable stiffness (stretch resistance) in resting muscles

Question 6

what is low muscle tone?

Answer 6

= hypotonia or flaccidity
LMN lesions
Acute UMN lesions (usually temporary)
Developmental disorders

Question 7

what is high muscle tone?

Answer 7

=hypertonia
chronic UMN lesions
some basal ganglia disorders may be specific or rigid

Question 8

what is the brain

Answer 8

the mediator

Question 9

what is the spinal cord

Answer 9

router

Question 10

what are the peripheral nerves in the system

Answer 10

the wires sending signals

Question 11

no dampening of signals would mean?

Answer 11

increased tone, spasticity, rigidity, and a cycling of stretch reflexes

Question 12

what is paresis

Answer 12

a decrease in the amount of movement or strength
hemi-
one side of the body
para-
caudal half
tetra- all limbs

Question 13

what is plegia paralysis

Answer 13

a complete loss of the ability to move
hemi
para
tetra (used to be quad)

Question 14

what is atrophy

Answer 14

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

Question 15

what are the types of involuntary muscle contractions

Answer 15

muscle spasms
cramps
myoclonous
fasciculations
fibrillations
abnormal movements due to basal ganglia dysfunction

Question 16

what is a muscle spasm

Answer 16

sudden involuntary contractions of muscles

Question 17

what is a cramp?

Answer 17

particularly severe and painful muscle spasms

Question 18

what is a myoclonus

Answer 18

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)

Question 19

what is a fasciculation

Answer 19

Quick twitches of single motor unit muscle fibers that are visible on the surface of the skin

Question 20

what is a filibration

Answer 20

Brief contractions of single muscle fibers not visible on the surface of the skin
May occur with UMN or LMN disorders

Question 21

what is spinal/cerebral shock?

Answer 21

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

Question 22

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?

Answer 22

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

Question 23

what is the pathology of a motor neuron lesion?

Answer 23

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

Question 24

What would be the difference between a c7 and c8 sensory loss

Answer 24

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)

Question 25

tell me about the autonomic nervous system

Answer 25

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)

Question 26

tell me about the sympathetic nervous system

Answer 26

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