Review > Lower Motor Neuron

Lower Motor Neuron
The lower motor neuron unit consists of the ventral horn cell within the spinal cord (or brain stem in the case of cranial nerves), the ventral root, peripheral nerves and neuromuscular junction. In purely muscular or LMN diseases, sensory function remains intact. However, in peripheral nerve diseases both sensory and motor axons run together so both may be affected.

LMN signs include:
• Hypotonia/flaccidity
• Flaccid paresis/paralysis
• Hyporeflexia/areflexia
• Early, pronounced muscle wasting

See figure of lower motor neuron unit (to figure 5)

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