Which muscular response is characteristic of a lower motor neuron (LMN) lesion?

In the context of a lower motor neuron lesion, the characteristic muscular response is flaccid and hypotonic. Lower motor neurons are responsible for directly innervating skeletal muscles, and when they are damaged or lesioned, the connection between the nervous system and the muscle fibers is disrupted. This disruption leads to a loss of voluntary and reflexive control of the affected muscles, resulting in muscle weakness and a reduction in muscle tone.

Flaccidity occurs because the muscle fibers are no longer receiving the necessary signals to contract, leading to a lack of tension in the muscles. Hypotonicity, meaning decreased muscle tone, also accompanies this because the muscles become less firm and more pliable. Patients with such lesions may exhibit muscle atrophy over time due to disuse and loss of neuromuscular function. Collectively, these symptoms are the hallmark indicators of lower motor neuron damage, setting them apart from other muscular responses associated with different types of motor neuron lesions.