NMJ Case

Question 1

cell bodies of somatic LMN are located in

Answer 1

• cranial nerve nuclei
• ventral horn of the spinal cord

Question 2

where does LMN synapse with the skeletal muscle?

Answer 2

neuromuscular junction

Question 3

Clinical Signs of Neuromuscular
Dysfunction?

Answer 3

1. weakness

Question 4

Acetylcholine is an important
neurotransmitter for what other types
of synapses?

Answer 4

Preganglionic sympathetic neurons

Preganglionic parasympathetic neurons

Postganglionic parasympathetic neurons

Neuromuscular junction

Question 5

order of functional loss with spinal cord dysfunction

Answer 5

1. proprioception lost first → loss of coordination/ataxia
2. lack of voluntary movement (motor function)
3. lack of superficial and deep pain → loss of somatosensory

Question 6

Why is pain lost last?

Answer 6

Pain fibers are small and lightly myelinated → most resistant to compression

Question 7

What anatomical factors determine order of functional loss?

Answer 7

Myelination
axon diameter
tract location within spinal cord

Question 8

acquired myasthenia gravis?

Answer 8

immune-mediated disease where antibody binds to AChR → deficiency of AChR

Question 9

In neuromuscular disease, are reflexes increased or decreased?

Answer 9

Decreased to absent (LMN pattern)

Question 10

What differentiates neuromuscular weakness from spinal cord weakness?

Answer 10

NM disease → no ataxia, no proprioceptive deficits; pure weakness only

Question 11

Do neuromuscular disorders affect proprioception?

Answer 11

No

Question 12

Does neuromuscular disease affect mentation?

Answer 12

No

Question 13

What examination findings support neuromuscular dysfunction?

Answer 13

Muscle atrophy or hypertrophy, decreased to absent reflexes

Question 14

hypocalcemia and myasthenia gravis are related to

Answer 14

junctionopathy

Question 15

hypokalemia and polymyositis are related to

Answer 15

myopathy