Motor Neurone Lesions

Question 1

Motor neurone lesions refers to a lesion in the ____ muscle control

a) Involuntary
b) Voluntary
c) Smooth
d) Cardiac

Answer 1

Motor neurone lesions refers to a lesion in the Voluntary muscle control

Question 2

Describe the location in which the upper motor neurones are found

Answer 2

• Upper motor neurones are located in the primary motor cortex
• Their axon spam into the spinal cord

Question 3

Motor neurones lesions are divided into two groups based on location.

Name these two groups of motor neurone lesions

Answer 3

Upper motor neurone lesions

Lower motor neurone lesions

Question 4

What is the action of the upper motor neurone

Answer 4

Action is to excite alpha motor neurones (either directly or via spinal interneurons)

Question 5

Classify a neurone lesion as upper indicates the lesion is located where

Answer 5

Upper motor neurone lesion indicates that the lesion is located above the anterior horn cell

Question 6

Describe the location in which the lower motor neurones are found

Answer 6

Lower motor neurones are the alpha motor neurones

The alpha motor neurones run from the spinal cord to the muscle

Question 7

What stimulates the lower motor neurone

Answer 7

They are excited by upper motor neurones either directly or via spinal interneurons

Question 8

Classify a neurone lesion as lower indicates the lesion is located where

Answer 8

Lower motor neurone lesions indicates that the lesion is either in the anterior horn cell or distal to the anterior horn cell

Question 9

Describe the clinical features of lower motor neurone lesions

Answer 9

Decrease multiple tone

Muscle wasting

Muscle weakness due to loss of muscle bulk

Fasciculations

Absence tendon jerk reflex

Negative babinski response

Question 10

Describe the clinical features of upper motor neurone lesions

Answer 10

No muscle wasting

No fasciculations

Increase in muscle tone - rigid

Muscle weakness due to inefficient recruitment of alpha motor neurones

Hyper- reflex of the tendon jerk reflex

Positive babinski response

Question 11

Fill in the blanks

Answer 11

Question 12

Why do we get weakness in lower motor neurone lesions

Answer 12

Due to the loss of muscle bulk

Question 13

Why do we get weakness in upper motor neurone lesions

Answer 13

Due to inefficient recruitment of alpha motor neurones