UMN vs LMN

Question 1

Pyramidal system

Answer 1

system of voluntary mvmt

Question 2

In the brain, motor neurons pass through the _________ _________ near the thalamus and basal ganglia

Answer 2

internal capsule

Question 3

normal motor function depends on the transmission from the brain to ___________ or _____ _____ by the _______; and from there to _____ ______ by ________

Answer 3

brain to brainstem or spinal cord, by the UMNs; & from there to skeletal muscles by LMNs

Question 4

brainstem is made up of what 3 parts

Answer 4

midbrain, pons, & medulla

Question 5

communication between UMNs and LMNs occur in the _____ ______

Answer 5

spinal cord

Question 6

What can cause UMN lesions?

Answer 6

Any injury to the brain such as stroke, infection, or tumor OR any injury to the brainstem or spinal cord, specifically, white matter of the spinal cord, where the UMNs are traveling through

Question 7

What can cause LMN lesions?

Answer 7

Any damage that occurs along the tract from spinal cord to skeletal muscle

Question 8

majority of UMNs that project from the motor cortex to the spinal cord are contained in the _______ _________ _________

Answer 8

lateral corticospinal tract

Question 9

neurons that will travel through the lateral corticospinal tract will cross over (decussate) at the _________________of the brainstem

Answer 9

medulla

Question 10

once the UMNs reach the correct spinal level, they synapse with LMNs at the ___________ of the spinal cord

Answer 10

anterior horn

Question 11

In general, motor neurons activated on one side of the brain will control movement on the __________ side

Answer 11

opposite

Question 12

Injury to axons leaving the spinal cord would cause damage to the ________ motor neurons

Answer 12

LMNs

Question 13

because these neurons start at the ventral grey matter of the spinal cord, injury to this part would cause ______________ motor neuron lesions

Answer 13

LMN

Question 14

signs of LMN lesion

Answer 14

• flaccid paralysis
• Muscle atrophy (because the neurons that supply the muscles are not getting there)
• absent plantar response (muscle is not getting the signal)
• fasciculations (some muscles are still getting transmission from LMNs that are not fully injured)
• negative babinski sign (no plantar response)

Question 15

signs of UMN lesions

Answer 15

• Minimal muscle atrophy
• Amplified deep tendon reflex
• absent or diminished superficial reflex
• • babinski sign (plantar response)