UMN and LMN signs

Question 1

What would you find on inspection for UMN?

What would you find on inspection for LMN?

2 causes of pronator drift

Answer 1

No fasciculation
Significant wasting (may atrophy or contractures) 

Wasting
Fasciculations

UMN lesion/LM weakness

Question 2

What would you find with pronator drift for UMN?

LMN?

Answer 2

May be present

May be some drift/movement of arms if weak or deafferented but not pronator

Question 3

Tone

UMN?

LMN?

Answer 3

Increased (spasticity)
+/- ankle clonus

Decreased or normal

Question 4

Power

UMN - Pyramidal - what does that mean?

LMN?

Answer 4

Extensors weaker than flexors in arms and vice versa in legs

Different patterns of weakness, depending on cause e.g. classically a proximal weakness in muscle disease, a distal weakness in peripheral neuropathy

Question 5

Reflexes

Answer 5

Exaggerated or brisk

Reduced or absent

Question 6

Plantar reflexes

UMN?

LMN?

Answer 6

Upgoing/extensor (Babinski positive)

Normal (downgoiing/flexor)