II. Physiology

  1. Corticospinal tract (motor, lateral cord) transmits motor signals from the cerebral cortex
    1. Fibers cross the midline at the Brain Stem and course to the contralateral Muscles
  2. Motor fibers Synapse in the anterior horn (grey matter of the spinal cord)
    1. Upper Motor Neurons (UMN) are from the cerebral cortex to the Synapse
      1. Affect the cerebral cortex, Brainstem and Corticospinal tracts
    2. Lower Motor Neurons (LMN) are from the Synapse to the Muscle
      1. Affect the anterior horn (spinal cord), nerve roots, and Peripheral Nerves

IV. Signs: Lower Motor Neuron Lesion findings

  1. Flaccid Paralysis
  2. Muscular atrophy
  3. Muscle fasciculations and fibrillations
  4. Hyporeflexia
  5. Absent Babinski Reflex

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Related Studies

Ontology: Lower motor neurone lesion (C0442865)

Concepts Pathologic Function (T046)
SnomedCT 264077003, 299737009
Italian Lesione del motoneurone inferiore, Lesione del motoneurone inferiore NAS
Dutch lagere motorische neuronlaesie NAO, lagere motorische neuronlaesie
French Lésion des motoneurones inférieurs SAI, LESION DU MOTONEURONE INFERIEUR, Lésion du motoneurone inférieur
German untere Motorneuronlaesion NNB, NEURONENSCHAEDIGUNG MOTORISCHE UN, untere Motorneuronlaesion
Portuguese Lesão traumática do neurónio motor inferior NE, LESAO DO NEURONIO MOTOR PERIFERIC, Lesão do neurónio motor inferior
Spanish Lesión de neurona motor inferior NEOM, lesión de la neurona motora inferior (hallazgo), lesión de la neurona motora inferior, Lesión de la segunda motoneurona
Japanese 下位運動ニューロンの病変NOS, 下位運動ニューロンの病変, カイウンドウニューロンノビョウヘン, カイウンドウニューロンノビョウヘンNOS
English LOWER MOTOR NEURONE LESION, Lower motor neurone lesion NOS, Lower motor neurone lesion (disorder), Lower motor neurone lesion, Lower motor neurone lesion (finding)
Czech Léze dolního motorického neuronu, Léze dolního motorického neuronu NOS
Hungarian Alsó motoneuron laesio, Alsó motoneuron laesio k.m.n.

Ontology: Lower motor neuron (C0524459)

Concepts Cell (T025)
SnomedCT 91770004
English lower motor neurons, lower motor neuron, neuron lower motor, Lower motor neuron, Lower motor neuron (cell)
Spanish neurona motora inferior (célula), neurona motora inferior