Lesion localization strategy

Question 1

what anatomical units are involved in UMNs?

Answer 1

• cortex
• subcortex
• brainstem
• cerebellum
• spinal cord

Question 2

what anatomical units are involved in LMNs?

Answer 2

• nerve root
• peripheral nerve
• NMJ
• muscle

once it leaves the spinal cord it is a LMN

Question 3

what are the characteristics of an UMN lesion?

Answer 3

• spasticity
• hyperreflexia
• hypertonicity
• pathological reflexes
• plantar extensor sign

Question 4

what are the characteristics of a LMN lesion?

Answer 4

• flaccidity
• hyporeflexia
• hypotonicity
• fasciculations** / atrophy

Question 5

apraxia

Answer 5

failure to know how to do something

Question 6

what are deficits pointing to the subcortex?

Answer 6

• visual field deficits (quandrantanopia and hemianopia)
• pure motor or pure sensory deficits or affecting entire side of body / more than one area**

**pathognomonic for subcortex

Question 7

definition: ataxia

Answer 7

incoordination OUT OF PROPORTION to the amount of paresis

Question 8

what is the pathognomonic feature of a spinal cord lesion?

Answer 8

myelopathy - spinal sensory level deficit

Question 9

what is the hallmark of NMJ lesion? what is a second finding?

Answer 9

• fluctuating motor weakness with easy fatigueability

- diurnal variation

Question 10

how do you differentiate nerve and muscle disorders?

Answer 10

NEUROPATHY

• sensory signs
• distal greater than proximal paresis

MYOPATHY

• absent sensory signs but possibly symptoms
• proximal greater than distal paresis