What is a common example of a lower motor neuron injury?

A lower motor neuron injury involves damage to the neurons that originate in the spinal cord and directly innervate skeletal muscles. This type of injury leads to muscle weakness, atrophy, and fasciculations due to the loss of motor neuron integrity.

Polio is a viral infection that specifically targets the lower motor neurons in the anterior horn of the spinal cord, leading to paralysis and muscle atrophy in the affected regions. This is a classic example of lower motor neuron injury because the disease disrupts the pathway that sends signals from the spinal cord to the muscles, resulting in the characteristic symptoms of muscle weakness and atrophy.

In contrast, conditions like multiple sclerosis, Huntington's disease, and Alzheimer's disease do not primarily affect lower motor neurons. Multiple sclerosis is an autoimmune condition that affects the central nervous system and can lead to upper motor neuron signs. Huntington's disease is a genetic disorder that primarily affects the basal ganglia and leads to motor and cognitive decline, while Alzheimer's disease is a neurodegenerative condition that primarily impacts cognitive functions rather than direct motor neuron pathways.