Will contraction of a muscle occur if the lower motor neurons serving it have been destroyed?

What about the UPPER ones?
Answer:
A controlled voluntary muscle contraction under these conditions will not occur. In fact over time a denervated muscle will turn largely into connective, non-contractile, tissue. This means that a person who has a say spinal cord injury over time will lose skeletal muscle. So if in the future the injury were to be corrected the persons muscles would be usless. Muscles can be kept alive using external muscle stimulators.

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Not in terms of voluntary movement, ie if you want to move your leg, but have no lower motor neurons, you won't be able to; but if the muscle were to get direct stimulus (like an electrical stimulus, shock) it would contract. I think. I believe they use something like that to help paralzyed people regain ability to walk.

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a lower motor neuron injury will leave you with a flaccid paralysis, meaning you'll have no voluntary ability to contract your muscles. the muscles may have involuntary spasms under certain circumstances, like if you become hypokalemic. also, like mentioned before, direct stimulation would also elicit an involuntary contraction.an upper motor neuron injury is different, depending on where the level of injury is. if the injury occurs at the spinal cord or brain level, then you may have a rigid paralysis, which is an abnormally sustained contraction of the affected muscle.

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