LMN, Lower Motor Neuron

Clinic

• LMN is an entity, which affects nerve fibers traveling from the lower motor neuron(s) in the Anterior horn of the spinal cord, or in the motor nuclei of the cranial nerves, to the relevant muscle(s).
• UMN (Upper motor neuron lesion) often presents with spastic paralysis – paralysis accompanied by severe hypertonia.

Sign / Symptoms

• Muscle paresis or paralysis / Strength decreased
• Fibrillations
• Fasciculations
• Hypotonia or Atonia
• Hypo reflexia
• Ascent extensor plantar reflex

Causes

Dynamic	Static
Guillain–Barré syndrome C. botulism ALS Progressive muscular atrophy Monomelic amyotrophy	Trauma to peripheral nerves Cauda equina syndrome

Differential diagnosis

• Myasthenia gravis

• Hypotonia / Flaccidity
• Ipsilateral (same side) weakness of individual muscles.
• Atrophy
• Weak or absent deep tendon plantar reflexes and abdominal reflexes
• Fasciculations (Twitching)

Miasms

Viruses that selectively attack ventral horn cells such as

• WNE
• PLV