QuestionSBA
QuestionChoice
This sign of a lower motor neurone lesion.

The damage to A-motor neurones with the lower motor neurones leads to less muscle contraction and therefore decreased use of the muscle.

This can lead to loss of muscle mass due to disuse.
10005775
e
Muscle Atrophy
QuestionChoice
This sign is elicited by firmly stroking the lateral border of the plantar surface of the foot. If positive, the big toe extends and the toes fan out with abduction.

A positive sign is present up until the age of 2. This is because the inhibitory neurones are not yet developed.

However, if over the age of two and the Babinski sign is present, it is suggestive that the inhibitory neurones are damaged and therefore is a lesion in the upper motor neurones.

Therefore, this is a normal finding.
10005772
b
Negative Babinski sign
QuestionChoice
Inhibitory neurones are found within the upper motor neurones which provide crucial regulation of muscle tone.

When these are damaged, descending inhibition is lost which results in brisk reflexes.
10005771
a
Brisk reflexes
QuestionChoice
This sign of a lower motor neurone lesion.

There is no damage to the inhibitory neurones found within the upper motor neurones, so these are still working optimally.

A-motor neurones are found within the lower motor neurones that are essential in muscle contraction. Damage to these, causes a loss of muscle tension at rest, i.e. a loss of muscle tone.
10005773
c
Loss of muscle tone
QuestionChoice
This sign of a lower motor neurone lesion.

A-motor neurones with the lower motor neurones that contribute to muscle contraction are damaged. This leads to an overall loss of tone. However, they can still fire spontaneously causing small contractions in the muscle unit which can be seen very subtly as twitching of the muscle.
10005774
d
Fasciculations
Concept
Chapter
2693
4386
Upper motor neuron lesions
Topic
152
Neuroscience
13701
56 year old female is referred to neurology due to progressive weakness in her left arm. She describes feeling numb in her hand and has recently been unable to open jars and write text messages using this hand.

The neurologist suspects amyotrophic lateral sclerosis presenting with upper motor neurone signs and symptoms.

What is another sign of an upper motor neurone lesion that may be found in this patient?
a